Detect a fetched image's format from its bytes once (closes #319)

magic.DetectFormat returns an imagerequest.Format. ValidateMagicBytes
returns the format it checked against the upstream Content-Type. The
cache stores that format in the source's row, so a variant made from a
cached source uses it too. The proxy hands it to Process, which still
refuses input libvips would load with another loader, such as an SVG
passing as AVIF. Format.MIMEType declares each MIME string once, and the
fetcher, the cache's variant read and the Accept matching use it.
magic.MIMEType, magic.ImageFormat, MIMEToImageFormat, magic's SVG
detection, detectFormat, formatFromString, FormatToMIME and
Result.InputFormat are gone.

Model: opus-5-5

TODO.md

@@ -30,66 +30,6 @@ P2: security: per-origin rate limiting
 
 # Completed Steps
 
-- 2026-10-27 the reconciliation pass skips a directory it cannot list and a file
-  whose info it cannot read, and goes on (closes #343). It stopped before its
-  later checks at a directory it could not list, or at a source or variant file
-  whose info it could not read.
-    - It logs the warning "skipped unreadable entry in cache directory", with
-      the path and the error.
-    - A file renamed or removed after its directory was listed gets no warning.
-    - `reconcileFiles` reads each file's info once, before the temp-file check,
-      and hands it to `sweepStaleTempFile`, `reconcileVariantFile` or
-      `reconcileSourceFile`.
-    - A cancelled context still stops the walk with its error.
-- 2026-10-26 the reconciliation pass drops a variant's accounting row only when
-  its file is missing (closes #340). Any other error reading the file's size
-  keeps the row. It dropped the row on any error and logged the file as missing.
-    - The kept row gets the warning "kept accounting row for unreadable variant
-      file", with the variant key and the error.
-    - The pass checks for `ErrNotFound`, which `FileStore.Size` returns for a
-      missing file.
-- 2026-10-26 on both image routes, a request is answered 499 and logged at info
-  level when its client goes away before its image is ready, unless it is the
-  request making the image (closes #339). It was answered 500 and logged at
-  error level, as pixa's own failure.
-    - The line is "client went away before the image was ready". It carries the
-      `request_id`, the host and the path.
-    - The 499 has no body, since nobody reads it.
-    - `serveImage` answers it before calling `respondImageError`, which cannot
-      see the request's context.
-    - An error wrapping `context.Canceled` while the request's context is live
-      is still answered 500 and logged at error level.
-- 2026-10-26 `README.md`'s Design section starts with a Concepts list (closes
-  #321). Each concept gets one sentence, under the name the code gives it.
-    - Storage calls the transformed images variants, in shorter sentences.
-    - Storage's paths end in the source key and the variant key.
-    - Storage lists the image cache's tables in the database.
-    - Architecture names `internal/providers`, and lists the packages that work
-      with the concepts.
-- 2026-10-26 one table in `internal/config` lists every setting once (closes
-  #320). `Config.settings` gives each setting's key, its environment variable
-  and the function that loads it.
-    - Most rows load through `field`, whose arguments give the setting's type,
-      its default and its check.
-    - `db_url` and `cache_max_bytes` have their own load functions. The default
-      of `db_url` comes from `state_dir`, and `cache_max_bytes` records whether
-      it is set.
-    - Loading, the unknown-key check, the unknown-variable check and the names
-      in error messages all read the table.
-    - `allowlist_hosts` loads as `referer_blocklist` does, through
-      `parseHostList`.
-    - The metrics username and password are checked together once the table has
-      loaded.
-    - When a config holds more than one invalid value, the error names the one
-      that comes first in the table.
-    - `README.md` lists the settings one item each, where it had a table. A test
-      checks that this list and `configs/config.example.yml` name exactly the
-      keys of the table.
-    - The key constants moved to the tests, their only users.
-    - Removed:
-        - `isKnownConfigKey`, `envVarNames`, `strictLoader` and `validate`
-        - `validateAllowlistHostsValue` and `getStringSlice`, with the three
-          tests of `getStringSlice`
 - 2026-10-26 a fetched image's format is detected from its bytes once, as an
   `imagerequest.Format` (closes #319). The upstream `Content-Type` check in the
   fetcher stays as the filter before downloading.
@@ -99,13 +39,11 @@ P2: security: per-origin rate limiting
     - `Format.MIMEType` gives each format's MIME type. The fetcher, the mock
       fetcher, the cache's read of a variant's type and the handler's `Accept`
       matching use it.
-    - `Cache.Source` returns a source's format, read from its file's first bytes
-      as `Cache.Variant` reads a variant's. A file in no source format is an
-      error, and the proxy fetches the source again.
+    - The cache stores a source's format in its `source_content` row, and
+      `Cache.Source` returns it. `Cache.PutSource` takes it.
     - The proxy hands the format to `ImageProcessor.Process`. The processor
       refuses input that libvips would load as another format, as before, with
-      `ErrUnsupportedInputFormat`. It refuses a format that is not one of the
-      six source formats the same way.
+      `ErrUnsupportedInputFormat`.
     - `internal/magic` no longer detects SVG, which pixa does not read. SVG data
       is `ErrUnknownFormat`.
     - Removed:

internal/config/config_internal_test.go

@@ -1,12 +1,97 @@
 package config
 
 import (
+	"os"
 	"path/filepath"
 	"testing"
 
 	"git.eeqj.de/sneak/smartconfig"
 )
 
+// writeTestConfig writes yamlContent to a temp config file and returns
+// the file path.
+func writeTestConfig(t *testing.T, yamlContent string) string {
+	t.Helper()
+
+	tmpDir := t.TempDir()
+	configPath := filepath.Join(tmpDir, "config.yml")
+
+	err := os.WriteFile(configPath, []byte(yamlContent), 0o600)
+	if err != nil {
+		t.Fatalf("failed to write test config: %v", err)
+	}
+
+	return configPath
+}
+
+// checkAllowlistHosts loads the config at configPath and asserts that
+// getStringSlice returns the three expected hosts.
+func checkAllowlistHosts(t *testing.T, configPath string) {
+	t.Helper()
+
+	sc, err := loadTestConfig(configPath)
+	if err != nil {
+		t.Fatalf("failed to load config: %v", err)
+	}
+
+	hosts := getStringSlice(sc)
+
+	if len(hosts) != 3 {
+		t.Errorf("expected 3 hosts, got %d: %v", len(hosts), hosts)
+	}
+
+	expected := []string{"static.sneak.cloud", "sneak.berlin", testHostS3}
+	for i, want := range expected {
+		if i >= len(hosts) {
+			t.Errorf("missing host at index %d: want %q", i, want)
+
+			continue
+		}
+
+		if hosts[i] != want {
+			t.Errorf("host[%d] = %q, want %q", i, hosts[i], want)
+		}
+	}
+}
+
+func TestGetStringSlice_YAMLList(t *testing.T) {
+	t.Parallel()
+
+	yamlContent := `
+allowlist_hosts:
+  - static.sneak.cloud
+  - sneak.berlin
+  - s3.sneak.cloud
+`
+
+	checkAllowlistHosts(t, writeTestConfig(t, yamlContent))
+}
+
+func TestGetStringSlice_CommaSeparated(t *testing.T) {
+	t.Parallel()
+
+	// Backwards compatibility with comma-separated string values.
+	yamlContent := `allowlist_hosts: "static.sneak.cloud, sneak.berlin, s3.sneak.cloud"`
+
+	checkAllowlistHosts(t, writeTestConfig(t, yamlContent))
+}
+
+func TestGetStringSlice_Empty(t *testing.T) {
+	t.Parallel()
+
+	configPath := writeTestConfig(t, `port: 8080`)
+
+	sc, err := loadTestConfig(configPath)
+	if err != nil {
+		t.Fatalf("failed to load config: %v", err)
+	}
+
+	hosts := getStringSlice(sc)
+	if len(hosts) != 0 {
+		t.Errorf("expected nil or empty slice, got %v", hosts)
+	}
+}
+
 // TestExampleConfigAllowlistsNoHost loads configs/config.example.yml
 // with a real signing key, as Getting Started in README.md has it copied
 // and edited, and checks that it allowlists no host: every image on an

internal/config/config_validation_internal_test.go

@@ -15,36 +15,8 @@ import (
 	_ "modernc.org/sqlite" // SQLite driver registration
 )
 
-// The config keys the tests name in the errors they expect.
-const (
-	keyDebug                      = "debug"
-	keyMaintenanceMode            = "maintenance_mode"
-	keyPort                       = "port"
-	keyStateDir                   = "state_dir"
-	keySentryDSN                  = "sentry_dsn"
-	keyDBURL                      = "db_url"
-	keyMetrics                    = "metrics"
-	keyMetricsUsername            = "metrics.username"
-	keyMetricsPassword            = "metrics.password"
-	keySigningKey                 = "signing_key"
-	keyAllowlistHosts             = "allowlist_hosts"
-	keyRefererBlocklist           = "referer_blocklist"
-	keyAllowHTTP                  = "allow_http"
-	keyUpstreamConnectionsPerHost = "upstream_connections_per_host"
-	keyUpstreamConnections        = "upstream_connections"
-	keyMaxConcurrentProcessing    = "max_concurrent_processing"
-	keyCacheMaxBytes              = "cache_max_bytes"
-	keyBlockedNetworks            = "blocked_networks"
-	keyTrustedProxies             = "trusted_proxies"
-	keyAccessControlAllowOrigin   = "access_control_allow_origin"
-	keyUpstreamFetchTimeout       = "upstream_fetch_timeout"
-	keyUpstreamMaxResponseSize    = "upstream_max_response_size"
-	keyDownstreamTimeout          = "downstream_timeout"
-	keyImageRequestsPerMinute     = "image_requests_per_minute"
-)
-
 // validTestSigningKey is a 32-character signing key that satisfies the
-// minimum length requirement in validateSigningKey.
+// minimum length requirement in validate().
 const validTestSigningKey = "0123456789abcdef0123456789abcdef"
 
 // signingKeyLine is a valid signing_key config line used as the base of

internal/config/documented_settings_internal_test.go

@@ -1,127 +0,0 @@
-package config
-
-import (
-	"os"
-	"path/filepath"
-	"regexp"
-	"strings"
-	"testing"
-)
-
-// TestReadmeNamesEverySetting checks that the list of settings in
-// README.md names exactly the keys of the settings table, one item each.
-// The list is the first one in the Configuration section, and it ends at
-// the first blank line. Each item starts with its key in backticks.
-func TestReadmeNamesEverySetting(t *testing.T) {
-	t.Parallel()
-
-	readme, err := os.ReadFile(filepath.Join("..", "..", "README.md"))
-	if err != nil {
-		t.Fatalf("failed to read README.md: %v", err)
-	}
-
-	_, section, found := strings.Cut(string(readme), "\n### Configuration\n")
-	if !found {
-		t.Fatal("README.md has no Configuration section")
-	}
-
-	// The section ends at the next heading of its level or above.
-	section, _, _ = strings.Cut(section, "\n## ")
-	section, _, _ = strings.Cut(section, "\n### ")
-
-	_, list, found := strings.Cut(section, "\n- ")
-	if !found {
-		t.Fatal("README.md's Configuration section has no list")
-	}
-
-	list, _, _ = strings.Cut("- "+list, "\n\n")
-
-	itemKey := regexp.MustCompile("^- `([^`]+)`")
-	named := map[string]bool{}
-
-	for line := range strings.SplitSeq(list, "\n") {
-		// A line that does not start with "- " goes on with the item above.
-		if !strings.HasPrefix(line, "- ") {
-			continue
-		}
-
-		match := itemKey.FindStringSubmatch(line)
-		if match == nil {
-			t.Errorf("README.md's list of settings has an item "+
-				"that does not start with a key in backticks: %s", line)
-
-			continue
-		}
-
-		if named[match[1]] {
-			t.Errorf("README.md's list of settings names %s twice", match[1])
-		}
-
-		named[match[1]] = true
-	}
-
-	for _, s := range new(Config).settings() {
-		if !named[s.key] {
-			t.Errorf("README.md's list of settings does not name %s", s.key)
-		}
-
-		delete(named, s.key)
-	}
-
-	for key := range named {
-		t.Errorf("README.md's list of settings names %s, "+
-			"which is not a setting", key)
-	}
-}
-
-// TestExampleConfigNamesEverySetting checks that
-// configs/config.example.yml names exactly the keys of the settings
-// table, each one set or commented out with "# ". A key line holds the
-// key, a colon and at most a one-word value, which tells it from a
-// comment line that starts with a word and a colon. An indented key is
-// inside the map of the key above it, as username is inside metrics.
-func TestExampleConfigNamesEverySetting(t *testing.T) {
-	t.Parallel()
-
-	const examplePath = "configs/config.example.yml"
-
-	example, err := os.ReadFile(filepath.Join("..", "..", examplePath))
-	if err != nil {
-		t.Fatalf("failed to read %s: %v", examplePath, err)
-	}
-
-	keyLine := regexp.MustCompile(`(?m)^(?:# )?( *)([a-z_]+):(?: \S+)?$`)
-	named := map[string]bool{}
-
-	var mapKey string
-
-	for _, match := range keyLine.FindAllStringSubmatch(string(example), -1) {
-		indent, key := match[1], match[2]
-		if indent == "" {
-			mapKey = key
-			named[key] = true
-
-			continue
-		}
-
-		// The key holding the map is not itself a setting.
-		delete(named, mapKey)
-
-		named[mapKey+"."+key] = true
-	}
-
-	// The env section sets environment variables; it is not a setting.
-	delete(named, "env")
-
-	for _, s := range new(Config).settings() {
-		if !named[s.key] {
-			t.Errorf("%s does not name %s", examplePath, s.key)
-		}
-
-		delete(named, s.key)
-	}
-
-	for key := range named {
-		t.Errorf("%s names %s, which is not a setting", examplePath, key)
-	}
-}

internal/config/env_internal_test.go

@@ -138,8 +138,7 @@ func TestPixaPortAbortsStartupPointingToPort(t *testing.T) {
 
 // TestSettingVariablesAndConfigPathAreAccepted checks that every
 // setting's variable and PIXA_CONFIG_PATH pass the check for unknown
-// PIXA_ variables. TestEnvironmentSetsEveryKey pins the names in the
-// settings table.
+// PIXA_ variables. TestEnvironmentSetsEveryKey pins the names in the list.
 func TestSettingVariablesAndConfigPathAreAccepted(t *testing.T) {
 	// A config file's env section loaded by another test can leave a
 	// PIXA_ variable set for the whole process, so every one is unset
@@ -160,8 +159,8 @@ func TestSettingVariablesAndConfigPathAreAccepted(t *testing.T) {
 
 	t.Setenv("PIXA_CONFIG_PATH", "/etc/pixa/config.yml")
 
-	for _, s := range new(Config).settings() {
-		t.Setenv(s.envVar, "")
+	for _, name := range envVarNames() {
+		t.Setenv(name, "")
 	}
 
 	err := validateKnownEnvVars()

internal/database/concurrent_writes_internal_test.go

@@ -122,7 +122,7 @@ func writeConcurrently(t *testing.T, db *sql.DB) {
 // record again.
 func writeLikeOneRequest(ctx context.Context, db *sql.DB, key string) error {
 	_, err := db.ExecContext(ctx, `INSERT INTO source_content
-		(source_key, size_bytes) VALUES (?, 1)`, key)
+		(source_key, size_bytes, format) VALUES (?, 1, 'jpeg')`, key)
 	if err != nil {
 		return fmt.Errorf("storing a source: %w", err)
 	}

internal/db/migrations/001_schema.sql

@@ -3,10 +3,12 @@
 
 -- Source images, one row per source URL
 -- Files stored at: cache/sources/<ab>/<cd>/<source_key>, where source_key
--- is the SHA-256 of the source's host, path and query
+-- is the SHA-256 of the source's host, path and query. format is the
+-- image's format, detected from its first bytes when it was fetched.
 CREATE TABLE IF NOT EXISTS source_content (
     source_key TEXT PRIMARY KEY,
     size_bytes INTEGER NOT NULL,
+    format TEXT NOT NULL,
     last_accessed_at DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP
 );
 CREATE INDEX IF NOT EXISTS idx_source_content_last_accessed

internal/handlers/client_gone_internal_test.go

@@ -1,177 +0,0 @@
-package handlers
-
-import (
-	"bytes"
-	"context"
-	"encoding/json"
-	"log/slog"
-	"net/http"
-	"net/http/httptest"
-	"slices"
-	"testing"
-	"time"
-
-	"github.com/go-chi/chi/v5/middleware"
-	"sneak.berlin/go/pixa/internal/httpfetcher"
-	"sneak.berlin/go/pixa/internal/imagerequest"
-)
-
-// heldFetcher sends on started when a fetch begins, and holds the fetch until
-// release is closed. It then fails the fetch as an upstream error.
-type heldFetcher struct {
-	started chan struct{}
-	release chan struct{}
-}
-
-// Fetch sends on f.started, waits for f.release to be closed, and returns
-// httpfetcher.ErrUpstreamError.
-func (f heldFetcher) Fetch(
-	context.Context, imagerequest.Source,
-) (*httpfetcher.FetchResult, error) {
-	f.started <- struct{}{}
-
-	<-f.release
-
-	return nil, httpfetcher.ErrUpstreamError
-}
-
-// readLogLines decodes the JSON log lines in logs.
-func readLogLines(t *testing.T, logs *bytes.Buffer) []map[string]any {
-	t.Helper()
-
-	t.Logf("logged:\n%s", logs.String())
-
-	var lines []map[string]any
-
-	dec := json.NewDecoder(logs)
-	for dec.More() {
-		var line map[string]any
-
-		err := dec.Decode(&line)
-		if err != nil {
-			t.Fatalf("decoding log line: %v", err)
-		}
-
-		lines = append(lines, line)
-	}
-
-	return lines
-}
-
-// TestImageRoutes_ClientGoneWhileWaitingAnswers499 checks that both image
-// routes answer 499 to a request whose client goes away while it waits for an
-// image another request is making. A first request's fetch is held, so the
-// image is being made, and a second request for the same image waits for it
-// until its client goes away. The second request must be logged once at info
-// level with its request ID and the source host and path. Nothing may be
-// logged at error level.
-func TestImageRoutes_ClientGoneWhileWaitingAnswers499(t *testing.T) {
-	t.Parallel()
-
-	const requestID = "test-request-id"
-
-	for route, imageURL := range photoURLsByRoute() {
-		t.Run(route, func(t *testing.T) {
-			t.Parallel()
-
-			var logs bytes.Buffer
-
-			fetcher := heldFetcher{started: make(chan struct{}), release: make(chan struct{})}
-			h, routes := newRoutesFetchingThrough(t, fetcher,
-				slog.New(slog.NewJSONHandler(&logs, nil)))
-			target := imageURL(t, h)
-
-			firstDone := make(chan struct{})
-
-			go func() {
-				defer close(firstDone)
-
-				sendGet(t, routes, target)
-			}()
-
-			<-fetcher.started
-
-			ctx, cancel := context.WithCancel(context.WithValue(t.Context(),
-				middleware.RequestIDKey, requestID))
-			rec := httptest.NewRecorder()
-			secondDone := make(chan struct{})
-
-			go func() {
-				defer close(secondDone)
-
-				routes.ServeHTTP(rec, httptest.NewRequestWithContext(
-					ctx, http.MethodGet, target, nil))
-			}()
-
-			// Give the second request time to start waiting for the first
-			// request's image. The fetch is still held, so the second request
-			// can end only because its client went away
-			time.Sleep(100 * time.Millisecond)
-			cancel()
-			<-secondDone
-
-			close(fetcher.release)
-			<-firstDone
-
-			if rec.Code != 499 {
-				t.Errorf("status = %d, want 499", rec.Code)
-			}
-
-			var clientGoneLines int
-
-			for _, line := range readLogLines(t, &logs) {
-				if line["level"] == slog.LevelError.String() {
-					t.Errorf("logged at error level: %v", line["msg"])
-				}
-
-				if line["level"] == slog.LevelInfo.String() &&
-					line["msg"] == "client went away before the image was ready" &&
-					line["request_id"] == requestID &&
-					line["host"] == signedHost &&
-					line["path"] == photoPath {
-					clientGoneLines++
-				}
-			}
-
-			if clientGoneLines != 1 {
-				t.Errorf("info line naming the request logged %d times, want 1",
-					clientGoneLines)
-			}
-		})
-	}
-}
-
-// TestImageRoutes_CanceledWithLiveRequestAnswers500 checks that both image
-// routes answer 500, logged as "failed to get image" at error level, for an
-// image service error that wraps context.Canceled while the request's own
-// context is live. Its client has not gone away, so the cancellation is
-// pixa's own failure.
-func TestImageRoutes_CanceledWithLiveRequestAnswers500(t *testing.T) {
-	t.Parallel()
-
-	for route, imageURL := range photoURLsByRoute() {
-		t.Run(route, func(t *testing.T) {
-			t.Parallel()
-
-			var logs bytes.Buffer
-
-			h, routes := newRoutesFetchingThrough(t,
-				failingFetcher{err: context.Canceled},
-				slog.New(slog.NewJSONHandler(&logs, nil)))
-
-			rec := sendGet(t, routes, imageURL(t, h))
-			if rec.Code != http.StatusInternalServerError {
-				t.Errorf("status = %d, want %d",
-					rec.Code, http.StatusInternalServerError)
-			}
-
-			if !slices.ContainsFunc(readLogLines(t, &logs),
-				func(line map[string]any) bool {
-					return line["level"] == slog.LevelError.String() &&
-						line["msg"] == "failed to get image"
-				}) {
-				t.Error(`no "failed to get image" line logged at error level`)
-			}
-		})
-	}
-}

internal/handlers/image.go

@@ -1,7 +1,6 @@
 package handlers
 
 import (
-	"context"
 	"errors"
 	"fmt"
 	"io"
@@ -20,12 +19,6 @@ import (
 	"sneak.berlin/go/pixa/internal/magic"
 )
 
-// statusClientClosedRequest is the status nginx calls "client closed
-// request". The image routes answer it when the client goes away before its
-// image is ready, unless its request is the one making the image. Nobody reads
-// it; it is for logs and metrics.
-const statusClientClosedRequest = 499
-
 // HandleImage handles the main image proxy route:
 // /v1/image/<host>/<path>/<width>x<height>.<format>, or with no format
 // /v1/image/<host>/<path>/<width>x<height>
@@ -352,8 +345,7 @@ func notModified(w http.ResponseWriter, r *http.Request, etag string) bool {
 // serveImage serves the image that req asks for. Both image routes call it
 // once they have the request and its URL's expiry, which ends the
 // Cache-Control max-age. It chooses the format for the format auto, answers
-// If-None-Match with 304 and HEAD with the headers only. It answers 499 when
-// the image service stopped because the client went away, and any other error
+// If-None-Match with 304 and HEAD with the headers only, and answers an error
 // of the image service with respondImageError.
 func (s *Handlers) serveImage(
 	w http.ResponseWriter, r *http.Request,
@@ -370,21 +362,6 @@ func (s *Handlers) serveImage(
 	startTime := time.Now()
 
 	resp, err := s.imgSvc.Get(r.Context(), req)
-
-	// The client went away before its image was ready, which is not pixa's
-	// failure. A cancellation while the request's context is live is pixa's,
-	// and respondImageError answers it 500.
-	if errors.Is(err, context.Canceled) && r.Context().Err() != nil {
-		s.log.Info("client went away before the image was ready",
-			"request_id", middleware.GetReqID(r.Context()),
-			"host", req.Source.Host,
-			"path", req.Source.Path,
-		)
-		w.WriteHeader(statusClientClosedRequest)
-
-		return
-	}
-
 	if err != nil {
 		s.respondImageError(w, req, err)
 

internal/imageprocessor/imageprocessor.go

@@ -113,8 +113,7 @@ var ErrUnsupportedOutputFormat = errors.New("unsupported output format")
 // ErrUnsupportedInputFormat is returned, before the input is decoded, when
 // libvips reads the input's first bytes as another format than its source
 // format, or as none. An SVG whose first bytes pass the first-bytes check for
-// AVIF is one example. A source format other than the six pixa reads is also
-// refused with it.
+// AVIF is one example.
 var ErrUnsupportedInputFormat = errors.New("unsupported input format")
 
 // ErrTooManyImages is returned when MaxConcurrentProcessing images are being
@@ -183,11 +182,14 @@ func (p *ImageProcessor) Process(
 		return nil, err
 	}
 
-	// Input libvips would not load as sourceFormat is refused before it is
-	// decoded
-	err = checkInputFormat(data, sourceFormat)
-	if err != nil {
-		return nil, err
+	// govips picks the libvips loader from the input's first bytes with
+	// DetermineImageType. Input it would not load with the loader of
+	// sourceFormat is refused before libvips reads it. An SVG whose first
+	// bytes pass the first-bytes check for AVIF is one, which librsvg would
+	// otherwise render.
+	if vips.DetermineImageType(data) != vipsImageType(sourceFormat) {
+		return nil, fmt.Errorf("%w: libvips does not read the input as %s",
+			ErrUnsupportedInputFormat, sourceFormat)
 	}
 
 	// Decode image
@@ -358,28 +360,6 @@ func (p *ImageProcessor) readInput(input io.Reader) ([]byte, error) {
 	return data, nil
 }
 
-// checkInputFormat returns ErrUnsupportedInputFormat unless libvips would
-// load data with the loader of sourceFormat. govips picks the libvips loader
-// from the input's first bytes with DetermineImageType. It refuses an SVG
-// whose first bytes pass the first-bytes check for AVIF, which librsvg would
-// otherwise render.
-func checkInputFormat(data []byte, sourceFormat imagerequest.Format) error {
-	// A format with no loader, such as orig or auto, has the type govips also
-	// gives input it cannot read, which the check below would let through.
-	sourceType := vipsImageType(sourceFormat)
-	if sourceType == vips.ImageTypeUnknown {
-		return fmt.Errorf("%w: %q is not a source format",
-			ErrUnsupportedInputFormat, sourceFormat)
-	}
-
-	if vips.DetermineImageType(data) != sourceType {
-		return fmt.Errorf("%w: libvips does not read the input as %s",
-			ErrUnsupportedInputFormat, sourceFormat)
-	}
-
-	return nil
-}
-
 // vipsImageType returns the govips image type whose libvips loader reads
 // format. orig and auto stand for another format, so they have
 // vips.ImageTypeUnknown, which govips has no loader for.

internal/imageprocessor/source_formats_internal_test.go

@@ -2,7 +2,6 @@ package imageprocessor
 
 import (
 	"bytes"
-	"errors"
 	"io"
 	"testing"
 
@@ -49,27 +48,3 @@ func TestImageProcessor_LoadsEachSourceFormat(t *testing.T) {
 		}
 	}
 }
-
-// TestImageProcessor_NotASourceFormatRefused verifies that a source format
-// other than the six, such as orig, auto or none, is refused with
-// ErrUnsupportedInputFormat. The input is text, which libvips reads as no
-// format.
-func TestImageProcessor_NotASourceFormatRefused(t *testing.T) {
-	t.Parallel()
-
-	proc := New(Params{MaxInputBytes: 50 << 20, MaxConcurrentProcessing: 1})
-
-	for _, sourceFormat := range []imagerequest.Format{
-		imagerequest.FormatOriginal, imagerequest.FormatAuto, "",
-	} {
-		result, err := proc.Process(t.Context(),
-			bytes.NewReader([]byte("this is text, not an image")), sourceFormat,
-			&imagerequest.Transform{Format: imagerequest.FormatJPEG})
-		t.Logf("source format %q: error = %v", sourceFormat, err)
-
-		if result != nil || !errors.Is(err, ErrUnsupportedInputFormat) {
-			t.Errorf("Process() with source format %q = %v, error %v; want %v",
-				sourceFormat, result, err, ErrUnsupportedInputFormat)
-		}
-	}
-}

internal/imageproxy/imageproxy.go

@@ -303,10 +303,9 @@ func withoutCancelKeepingDeadline(
 	return context.WithDeadline(context.WithoutCancel(ctx), deadline)
 }
 
-// loadCachedSource opens src's cached source, reading only the first bytes,
-// which give its format, and returns it with its size and its format. It
-// returns nil if the source is not in the cache, cannot be read, is in no
-// source format or exceeds maxResponseSize.
+// loadCachedSource opens src's cached source, without reading it, and
+// returns it with its size and its format; nil if it is not in the cache,
+// cannot be read, is empty or exceeds maxResponseSize.
 func (p *Proxy) loadCachedSource(
 	ctx context.Context, src imagerequest.Source,
 ) (io.ReadCloser, int64, imagerequest.Format) {
@@ -334,6 +333,12 @@ func (p *Proxy) loadCachedSource(
 		return nil, 0, ""
 	}
 
+	if size == 0 {
+		_ = reader.Close()
+
+		return nil, 0, ""
+	}
+
 	return reader, size, format
 }
 
@@ -452,7 +457,8 @@ func (p *Proxy) fetchAndProcess(
 	}
 
 	// Store source content
-	_, err = p.cache.PutSource(ctx, req.Source, bytes.NewReader(sourceData))
+	_, err = p.cache.PutSource(ctx, req.Source, sourceFormat,
+		bytes.NewReader(sourceData))
 	if err != nil {
 		p.log.Warn("failed to store source content", "error", err)
 		// Continue even if caching fails

internal/imageproxy/max_concurrent_processing_internal_test.go

@@ -58,11 +58,10 @@ func holdProcessingSlot(
 
 // TestProxy_Get_WaitsForSlotBeforeReadingCachedSource checks that a
 // request whose source is cached holds none of it while it waits for a
-// processing slot: past the first bytes, which give the source's format, it
-// reads the cached file only once it has a slot. With the only slot held, a
-// request for a new width of the cached 100x100 photo waits; the cached file
-// is then rewritten as a 100x50 image before the slot is freed, so the
-// request must answer with that image scaled to 40x20.
+// processing slot: it reads the cached file only once it has a slot. With
+// the only slot held, a request for a new width of the cached 100x100 photo
+// waits; the cached file is then rewritten as a 100x50 image before the slot
+// is freed, so the request must answer with that image scaled to 40x20.
 func TestProxy_Get_WaitsForSlotBeforeReadingCachedSource(t *testing.T) {
 	t.Parallel()
 

internal/imageproxy/partial_cache_files_internal_test.go

@@ -7,7 +7,6 @@ import (
 	"testing"
 
 	"sneak.berlin/go/pixa/internal/imagerequest"
-	"sneak.berlin/go/pixa/internal/imgcache"
 )
 
 // getImage calls Get for req and returns the image it answered with and
@@ -105,40 +104,6 @@ func TestProxy_Get_FetchesAgainForRemovedCachedSource(t *testing.T) {
 	}
 }
 
-// TestProxy_Get_FetchesAgainSourceOfNoSourceFormat replaces the cached
-// source's file with text. The next request for a new size of the source
-// must fetch it again and cache it whole.
-func TestProxy_Get_FetchesAgainSourceOfNoSourceFormat(t *testing.T) {
-	t.Parallel()
-
-	svc, fixtures := setupTestProxy(t)
-
-	getImage(t, svc, photoVariant(fixtures, 85, imagerequest.FitCover))
-
-	path := cachedSourcePath(t, svc, photoVariant(fixtures, 85, imagerequest.FitCover))
-	wholeSize := fileSize(t, path)
-
-	err := os.WriteFile(path, []byte("this is text, not an image"),
-		imgcache.StorageFilePerm)
-	if err != nil {
-		t.Fatalf("replacing the source's file: %v", err)
-	}
-
-	getImage(t, svc, photoVariant(fixtures, 40, imagerequest.FitCover))
-
-	fetches := readCounters(t, svc).upstreamFetchCount
-	t.Logf("upstream fetches = %d", fetches)
-
-	if fetches != 2 {
-		t.Errorf("upstream fetches = %d, want 2", fetches)
-	}
-
-	size := fileSize(t, path)
-	if size != wholeSize {
-		t.Errorf("cached source is %d bytes, want %d", size, wholeSize)
-	}
-}
-
 // TestProxy_Get_ConvertsAgainForRemovedCachedVariant caches a variant of
 // the photo and removes its row and file, as the reconciliation pass does
 // when the file is empty or cut short. internal/imgcache tests that the

internal/imgcache/cache.go

@@ -228,10 +228,9 @@ func (c *Cache) PutVariant(
 }
 
 // Source opens the cached source of src and returns a reader, its size in
-// bytes and its format, read from the file's first bytes. A source whose row
-// or file is missing is ErrNotFound, as is any source of a disabled cache; a
-// file whose first bytes are not those of a source format is another error.
-// A source it opens has its access time handed to the background writer
+// bytes and its format, the one PutSource stored with it. A source whose row
+// or file is missing is ErrNotFound, as is any source of a disabled cache. A
+// source it opens has its access time handed to the background writer
 // without waiting (see touchSourceContent).
 func (c *Cache) Source(
 	ctx context.Context, src imagerequest.Source,
@@ -242,38 +241,32 @@ func (c *Cache) Source(
 
 	key := src.Key()
 
-	var rowExists bool
+	var format imagerequest.Format
 
 	err := c.db.QueryRowContext(ctx, `
-		SELECT EXISTS(SELECT 1 FROM source_content WHERE source_key = ?)
-	`, string(key)).Scan(&rowExists)
+		SELECT format FROM source_content WHERE source_key = ?
+	`, string(key)).Scan(&format)
+	if errors.Is(err, sql.ErrNoRows) {
+		return nil, 0, "", ErrNotFound
+	}
+
 	if err != nil {
 		return nil, 0, "", fmt.Errorf("failed to lookup source: %w", err)
 	}
 
-	if !rowExists {
-		return nil, 0, "", ErrNotFound
-	}
-
 	file, size, err := c.srcContent.Open(string(key))
 	if err != nil {
 		return nil, 0, "", err
 	}
 
-	format, err := readFormat(file)
-	if err != nil {
-		_ = file.Close()
-
-		return nil, 0, "", err
-	}
-
 	c.touchSourceContent(key)
 
 	return file, size, format, nil
 }
 
-// PutSource stores fetched source content: it writes the file named by
-// the source's key, then the source's row. When the row cannot be written
+// PutSource stores fetched source content and its format, which magic
+// detected from its first bytes. It writes the file named by the source's
+// key, then the source's row with the format. When the row cannot be written
 // the file is removed and the store fails, as a file with no row is never
 // served or evicted; if that removal fails too, the next reconciliation
 // pass removes the file. On a disabled cache it is a no-op returning an
@@ -281,6 +274,7 @@ func (c *Cache) Source(
 func (c *Cache) PutSource(
 	ctx context.Context,
 	src imagerequest.Source,
+	format imagerequest.Format,
 	content io.Reader,
 ) (imagerequest.SourceKey, error) {
 	if c.config.MaxBytes == 0 {
@@ -302,12 +296,13 @@ func (c *Cache) PutSource(
 	size := int64(len(data))
 
 	_, err = c.db.ExecContext(ctx, `
-		INSERT INTO source_content (source_key, size_bytes)
-		VALUES (?, ?)
+		INSERT INTO source_content (source_key, size_bytes, format)
+		VALUES (?, ?, ?)
 		ON CONFLICT(source_key) DO UPDATE SET
 			size_bytes = excluded.size_bytes,
+			format = excluded.format,
 			last_accessed_at = CURRENT_TIMESTAMP
-	`, string(key), size)
+	`, string(key), size, string(format))
 	if err != nil {
 		deleteErr := c.srcContent.Delete(string(key))
 		if deleteErr != nil {
@@ -449,9 +444,9 @@ func (c *Cache) cleanExpiredBatch(ctx context.Context) (int64, error) {
 	return deleted, nil
 }
 
-// readFormat reads the first bytes of a source or variant file, without
-// moving its offset, and returns the format they show. Sources and variants
-// are in the same six formats.
+// readFormat reads the first bytes of content, without moving its offset,
+// and returns the format they show. pixa writes each format it reads, so
+// that is an output format.
 func readFormat(content io.ReaderAt) (imagerequest.Format, error) {
 	firstBytes := make([]byte, magic.MinMagicBytes)
 

internal/imgcache/eviction.go

@@ -515,15 +515,12 @@ func (c *Cache) reconcileAccounting(ctx context.Context) error {
 }
 
 // reconcileFiles walks baseDir, one of the cache's storage directories,
-// sweeping stale temp files and passing each other file, with its info and
-// name, to reconcileFile. It skips a directory it cannot list and a file
-// whose info it cannot read, so one such entry does not stop the pass. It
-// logs a warning naming the path and the error. A file renamed or removed
-// after its directory was listed is skipped with no warning. Once ctx is
-// cancelled it stops at the next file and returns ctx's error.
+// sweeping stale temp files and passing each other file, with its name, to
+// reconcileFile. Once ctx is cancelled it stops at the next file and
+// returns ctx's error.
 func (c *Cache) reconcileFiles(
 	ctx context.Context, baseDir string,
-	reconcileFile func(path string, info fs.FileInfo, name string) error,
+	reconcileFile func(path string, entry fs.DirEntry, name string) error,
 ) error {
 	return filepath.WalkDir(
 		baseDir,
@@ -532,38 +529,19 @@ func (c *Cache) reconcileFiles(
 				return ctx.Err()
 			}
 
-			if err != nil {
-				c.log.Warn("skipped unreadable entry in cache directory",
-					"path", path, "error", err)
-
-				return nil
-			}
-
-			if entry.IsDir() {
-				return nil
-			}
-
-			info, err := entry.Info()
-			if errors.Is(err, fs.ErrNotExist) {
-				return nil
-			}
-
-			if err != nil {
-				c.log.Warn("skipped unreadable entry in cache directory",
-					"path", path, "error", err)
-
-				return nil
+			if err != nil || entry.IsDir() {
+				return err
 			}
 
 			name := entry.Name()
 
 			if strings.HasPrefix(name, tempFilePrefix) {
-				c.sweepStaleTempFile(path, info)
+				c.sweepStaleTempFile(path, entry)
 
 				return nil
 			}
 
-			return reconcileFile(path, info, name)
+			return reconcileFile(path, entry, name)
 		},
 	)
 }
@@ -573,8 +551,8 @@ func (c *Cache) reconcileFiles(
 // and sweeping stale temp files.
 func (c *Cache) reconcileVariantFiles(ctx context.Context) error {
 	return c.reconcileFiles(ctx, c.variants.baseDir,
-		func(path string, info fs.FileInfo, name string) error {
-			return c.reconcileVariantFile(ctx, path, info, imagerequest.VariantKey(name))
+		func(path string, entry fs.DirEntry, name string) error {
+			return c.reconcileVariantFile(ctx, path, entry, imagerequest.VariantKey(name))
 		})
 }
 
@@ -584,11 +562,16 @@ func (c *Cache) reconcileVariantFiles(ctx context.Context) error {
 // crash or a restored snapshot can leave it, is removed with its row and
 // a warning naming it, so the variant is converted again.
 func (c *Cache) reconcileVariantFile(
-	ctx context.Context, path string, info fs.FileInfo, cacheKey imagerequest.VariantKey,
+	ctx context.Context, path string, entry fs.DirEntry, cacheKey imagerequest.VariantKey,
 ) error {
+	info, err := entry.Info()
+	if err != nil {
+		return fmt.Errorf("failed to stat variant file: %w", err)
+	}
+
 	var recordedSize int64
 
-	err := c.db.QueryRowContext(ctx,
+	err = c.db.QueryRowContext(ctx,
 		`SELECT size_bytes FROM variant_content WHERE cache_key = ?`, string(cacheKey),
 	).Scan(&recordedSize)
 
@@ -630,9 +613,7 @@ func (c *Cache) adoptVariantFile(
 }
 
 // reconcileVariantRows drops accounting rows whose variant files are
-// missing, so the database never references deleted content. A file whose
-// size cannot be read for another reason may still be on disk, so its row
-// stays, with a warning naming its key and the error.
+// missing, so the database never references deleted content.
 func (c *Cache) reconcileVariantRows(ctx context.Context) error {
 	var after imagerequest.VariantKey
 
@@ -660,13 +641,6 @@ func (c *Cache) reconcileVariantRows(ctx context.Context) error {
 				continue
 			}
 
-			if !errors.Is(err, ErrNotFound) {
-				c.log.Warn("kept accounting row for unreadable variant file",
-					"cache_key", key, "error", err)
-
-				continue
-			}
-
 			_, err = c.db.ExecContext(ctx,
 				`DELETE FROM variant_content WHERE cache_key = ?`, string(key))
 			if err != nil {
@@ -731,8 +705,8 @@ func queryStringColumn[T ~string](
 // and sweeping stale temp files.
 func (c *Cache) reconcileSourceFiles(ctx context.Context) error {
 	return c.reconcileFiles(ctx, c.srcContent.baseDir,
-		func(path string, info fs.FileInfo, name string) error {
-			return c.reconcileSourceFile(ctx, path, info, imagerequest.SourceKey(name))
+		func(path string, entry fs.DirEntry, name string) error {
+			return c.reconcileSourceFile(ctx, path, entry, imagerequest.SourceKey(name))
 		})
 }
 
@@ -743,11 +717,16 @@ func (c *Cache) reconcileSourceFiles(ctx context.Context) error {
 // is removed with its row and a warning naming it, so the source is
 // fetched again.
 func (c *Cache) reconcileSourceFile(
-	ctx context.Context, path string, info fs.FileInfo, key imagerequest.SourceKey,
+	ctx context.Context, path string, entry fs.DirEntry, key imagerequest.SourceKey,
 ) error {
+	info, err := entry.Info()
+	if err != nil {
+		return fmt.Errorf("failed to stat source content file: %w", err)
+	}
+
 	var recordedSize int64
 
-	err := c.db.QueryRowContext(ctx,
+	err = c.db.QueryRowContext(ctx,
 		`SELECT size_bytes FROM source_content WHERE source_key = ?`,
 		string(key),
 	).Scan(&recordedSize)
@@ -912,12 +891,17 @@ func (c *Cache) correctUsageTotal(
 
 // sweepStaleTempFile removes a temp file left behind by a crashed
 // write once it is old enough that no in-flight store can own it.
-func (c *Cache) sweepStaleTempFile(path string, info fs.FileInfo) {
+func (c *Cache) sweepStaleTempFile(path string, entry fs.DirEntry) {
+	info, err := entry.Info()
+	if err != nil {
+		return
+	}
+
 	if time.Since(info.ModTime()) < staleTempFileAge {
 		return
 	}
 
-	err := os.Remove(path)
+	err = os.Remove(path)
 	if err != nil && !os.IsNotExist(err) {
 		c.log.Warn("failed to remove stale temp file", "path", path, "error", err)
 

internal/imgcache/eviction_internal_test.go

@@ -9,10 +9,8 @@ import (
 	"log/slog"
 	"os"
 	"path/filepath"
-	"slices"
 	"strings"
 	"sync"
-	"syscall"
 	"testing"
 	"time"
 
@@ -81,8 +79,9 @@ func newEvictionTestCache(t *testing.T, maxBytes int64) (*Cache, string) {
 	return cache, tmpDir
 }
 
-// storeEvictionTestSource stores content as a fetched source for
-// host/path and returns the resulting source key.
+// storeEvictionTestSource stores content as a fetched JPEG source for
+// host/path and returns the resulting source key. The cache does not read
+// the content, so it need not be a JPEG.
 func storeEvictionTestSource(
 	t *testing.T, cache *Cache, host, path string, content []byte,
 ) imagerequest.SourceKey {
@@ -101,7 +100,8 @@ func storeEvictionTestSource(
 	}
 
 	key, err := cache.PutSource(
-		context.Background(), req.Source, bytes.NewReader(content),
+		context.Background(), req.Source, imagerequest.FormatJPEG,
+		bytes.NewReader(content),
 	)
 	if err != nil {
 		t.Fatalf("PutSource(%s%s) failed: %v", host, path, err)
@@ -438,7 +438,8 @@ func assertDisabledCacheWritesAreNoOps(
 		t.Fatalf("PutVariant on disabled cache must be a no-op, got error: %v", err)
 	}
 
-	key, err := cache.PutSource(ctx, req.Source, bytes.NewReader([]byte("data")))
+	key, err := cache.PutSource(ctx, req.Source, imagerequest.FormatJPEG,
+		bytes.NewReader([]byte("data")))
 	if err != nil {
 		t.Fatalf("PutSource on disabled cache must be a no-op, got error: %v", err)
 	}
@@ -701,291 +702,6 @@ func TestStartEvictionReconcilesAccountingWithDisk(t *testing.T) {
 	}
 }
 
-// logLineNaming returns the first line of logs, written by slog's JSON
-// handler, that is at level and names the variant key, or "" if none is.
-func logLineNaming(logs, level string, key imagerequest.VariantKey) string {
-	for line := range strings.Lines(logs) {
-		if strings.Contains(line, `"level":"`+level+`"`) &&
-			strings.Contains(line, `"cache_key":"`+string(key)+`"`) {
-			return line
-		}
-	}
-
-	return ""
-}
-
-// TestReconcileVariantRowsDropsOnlyRowsOfMissingFiles gives
-// reconcileVariantRows two tracked variants. The first one's file is a
-// symbolic link to itself, so its size cannot be read. Its row must stay,
-// with a warning naming its key and the error. The second one has no file.
-// Its row must go, with the info line for a missing file.
-func TestReconcileVariantRowsDropsOnlyRowsOfMissingFiles(t *testing.T) {
-	t.Parallel()
-
-	cache, _ := newEvictionTestCache(t, 1<<30)
-	storeEvictionTestVariant(t, cache, testVariantKeyOne, []byte("variant one"))
-	storeEvictionTestVariant(t, cache, testVariantKeyTwo, []byte("variant two"))
-
-	unreadablePath := cache.variants.keyToPath(string(testVariantKeyOne))
-
-	err := os.Remove(unreadablePath)
-	if err != nil {
-		t.Fatalf("failed to remove the first variant's file: %v", err)
-	}
-
-	err = os.Symlink(unreadablePath, unreadablePath)
-	if err != nil {
-		t.Fatalf("failed to link the first variant's path to itself: %v", err)
-	}
-
-	_, statErr := os.Stat(unreadablePath)
-	if statErr == nil || errors.Is(statErr, fs.ErrNotExist) {
-		t.Fatalf("os.Stat() of the first variant: error = %v, "+
-			"want an error other than a missing file", statErr)
-	}
-
-	err = os.Remove(cache.variants.keyToPath(string(testVariantKeyTwo)))
-	if err != nil {
-		t.Fatalf("failed to remove the second variant's file: %v", err)
-	}
-
-	var logBuf bytes.Buffer
-
-	cache.log = slog.New(slog.NewJSONHandler(&logBuf, nil))
-
-	err = cache.reconcileVariantRows(t.Context())
-	t.Logf("reconcileVariantRows() error = %v, log: %s", err, logBuf.String())
-
-	if err != nil {
-		t.Fatalf("reconcileVariantRows() error = %v", err)
-	}
-
-	rowQuery := `SELECT COUNT(*) FROM variant_content WHERE cache_key = ?`
-
-	if n := countRows(t, cache, rowQuery, string(testVariantKeyOne)); n != 1 {
-		t.Errorf("the variant whose size cannot be read has %d rows, want 1", n)
-	}
-
-	if n := countRows(t, cache, rowQuery, string(testVariantKeyTwo)); n != 0 {
-		t.Errorf("the variant with no file has %d rows, want 0", n)
-	}
-
-	logs := logBuf.String()
-
-	warning := logLineNaming(logs, "WARN", testVariantKeyOne)
-	if !strings.Contains(warning, statErr.Error()) {
-		t.Errorf("no warning names %s and the error %q", testVariantKeyOne, statErr)
-	}
-
-	if line := logLineNaming(logs, "INFO", testVariantKeyOne); line != "" {
-		t.Errorf("the variant whose size cannot be read was logged at info: %s", line)
-	}
-
-	dropped := logLineNaming(logs, "INFO", testVariantKeyTwo)
-	if !strings.Contains(dropped, "dropped accounting row for missing variant file") {
-		t.Errorf("no info line says the file of %s is missing", testVariantKeyTwo)
-	}
-}
-
-// openDirectoryNearPathLimit makes a chain of directories inside dir, each
-// named with 255 zeros, the longest name Linux allows. Linux refuses a path
-// of 4096 bytes or more, and the chain goes as deep as it can below that.
-// It returns the chain's deepest directory as an os.Root, closed when the
-// test ends. An entry made through it with a 255-byte name has a path even
-// the root user cannot read. The os.Root can make that entry because it
-// names the entry only by its name, not by the whole path.
-func openDirectoryNearPathLimit(t *testing.T, dir string) *os.Root {
-	t.Helper()
-
-	name := strings.Repeat("0", 255)
-	deepest := dir
-
-	for len(filepath.Join(deepest, name)) < 4096 {
-		deepest = filepath.Join(deepest, name)
-	}
-
-	err := os.MkdirAll(deepest, StorageDirPerm)
-	if err != nil {
-		t.Fatalf("failed to make a chain of directories: %v", err)
-	}
-
-	root, err := os.OpenRoot(deepest)
-	if err != nil {
-		t.Fatalf("os.OpenRoot(%s) error = %v", deepest, err)
-	}
-
-	t.Cleanup(func() { _ = root.Close() })
-
-	return root
-}
-
-// makeEntriesTooLongToRead makes a new directory and a new file in the
-// deepest directory of the chain that openDirectoryNearPathLimit makes
-// inside dir. Even the root user can then neither list the new directory
-// nor read the new file's info. It returns the paths of the new directory
-// and the new file.
-func makeEntriesTooLongToRead(t *testing.T, dir string) []string {
-	t.Helper()
-
-	deepest := openDirectoryNearPathLimit(t, dir)
-	dirName := strings.Repeat("0", 255)
-
-	err := deepest.Mkdir(dirName, StorageDirPerm)
-	if err != nil {
-		t.Fatalf("failed to make a directory too deep to list: %v", err)
-	}
-
-	fileName := strings.Repeat("1", 255)
-
-	err = deepest.WriteFile(fileName, []byte("unreadable"), StorageFilePerm)
-	if err != nil {
-		t.Fatalf("failed to make a file too deep to read: %v", err)
-	}
-
-	return []string{
-		filepath.Join(deepest.Name(), dirName),
-		filepath.Join(deepest.Name(), fileName),
-	}
-}
-
-// makeTempFileTooLongToRead makes a temp file in the deepest directory of
-// the chain that openDirectoryNearPathLimit makes inside dir. Even the
-// root user then cannot read the temp file's info. It returns the temp
-// file's path.
-func makeTempFileTooLongToRead(t *testing.T, dir string) string {
-	t.Helper()
-
-	deepest := openDirectoryNearPathLimit(t, dir)
-	name := tempFilePrefix + strings.Repeat("1", 255-len(tempFilePrefix))
-
-	err := deepest.WriteFile(name, []byte("partial"), StorageFilePerm)
-	if err != nil {
-		t.Fatalf("failed to make a temp file too deep to read: %v", err)
-	}
-
-	return filepath.Join(deepest.Name(), name)
-}
-
-// assertSkippedEntryWarning checks that logs hold the warning "skipped
-// unreadable entry in cache directory" naming path, with the error
-// ENAMETOOLONG for that path.
-func assertSkippedEntryWarning(t *testing.T, logs, path string) {
-	t.Helper()
-
-	for line := range strings.Lines(logs) {
-		if strings.Contains(line, `"level":"WARN"`) &&
-			strings.Contains(line, `"msg":"skipped unreadable entry in cache directory"`) &&
-			strings.Contains(line, `"path":"`+path+`"`) &&
-			strings.Contains(line, path+": "+syscall.ENAMETOOLONG.Error()) {
-			return
-		}
-	}
-
-	t.Errorf("no warning %q names %s with the error %q",
-		"skipped unreadable entry in cache directory", path, syscall.ENAMETOOLONG)
-}
-
-// TestReconciliationGoesOnPastEntriesItCannotRead puts, in each storage
-// directory, a directory the pass cannot list and a file whose info it
-// cannot read. The pass walks each directory in name order, so it reaches
-// them before the cache's files, whose keys start with a letter. It must
-// log a warning naming each one's path and the error, and still do the
-// rest of its work:
-//   - adopt a variant file that has no row
-//   - drop the row of a variant whose file is missing
-//   - remove a source file that has no row
-//   - correct a wrong total cache usage
-func TestReconciliationGoesOnPastEntriesItCannotRead(t *testing.T) {
-	t.Parallel()
-
-	cache, _ := newEvictionTestCache(t, 1<<30)
-	ctx := t.Context()
-
-	untrackedVariant := []byte("variant with no row")
-
-	err := cache.variants.Write(string(testVariantKeyOne), untrackedVariant)
-	if err != nil {
-		t.Fatalf("failed to write a variant file with no row: %v", err)
-	}
-
-	storeEvictionTestVariant(t, cache, testVariantKeyTwo, []byte("variant two"))
-
-	err = os.Remove(cache.variants.keyToPath(string(testVariantKeyTwo)))
-	if err != nil {
-		t.Fatalf("failed to remove the second variant's file: %v", err)
-	}
-
-	untrackedSourceKey := "ffeeddcc0001"
-
-	err = cache.srcContent.Write(untrackedSourceKey, []byte("source with no row"))
-	if err != nil {
-		t.Fatalf("failed to write a source file with no row: %v", err)
-	}
-
-	_, err = cache.db.ExecContext(ctx,
-		`UPDATE cache_usage SET total_size_bytes = 1 WHERE id = 1`)
-	if err != nil {
-		t.Fatalf("failed to set a wrong total: %v", err)
-	}
-
-	unreadable := slices.Concat(
-		makeEntriesTooLongToRead(t, cache.variants.baseDir),
-		makeEntriesTooLongToRead(t, cache.srcContent.baseDir),
-	)
-
-	logs := reconcileAsAtStartup(t, cache)
-
-	for _, path := range unreadable {
-		assertSkippedEntryWarning(t, logs, path)
-	}
-
-	rowQuery := `SELECT COUNT(*) FROM variant_content WHERE cache_key = ?`
-
-	if n := countRows(t, cache, rowQuery, string(testVariantKeyOne)); n != 1 {
-		t.Errorf("the variant file with no row got %d rows, want 1", n)
-	}
-
-	if n := countRows(t, cache, rowQuery, string(testVariantKeyTwo)); n != 0 {
-		t.Errorf("the variant with no file kept %d rows, want 0", n)
-	}
-
-	_, err = os.Stat(cache.srcContent.keyToPath(untrackedSourceKey))
-	if err == nil {
-		t.Error("the source file with no row is still on disk")
-	}
-
-	usage, err := cache.UsageBytes(ctx)
-	if err != nil {
-		t.Fatalf("UsageBytes() error = %v", err)
-	}
-
-	if usage != int64(len(untrackedVariant)) {
-		t.Errorf("UsageBytes() = %d, want %d, the size of the adopted variant",
-			usage, len(untrackedVariant))
-	}
-}
-
-// TestReconciliationWarnsOfTempFilesWhoseInfoItCannotRead puts, in each
-// storage directory, a temp file whose info the pass cannot read. The
-// pass must log a warning naming each one's path and the error, as it
-// does for any other file whose info it cannot read.
-func TestReconciliationWarnsOfTempFilesWhoseInfoItCannotRead(t *testing.T) {
-	t.Parallel()
-
-	cache, _ := newEvictionTestCache(t, 1<<30)
-
-	unreadable := []string{
-		makeTempFileTooLongToRead(t, cache.variants.baseDir),
-		makeTempFileTooLongToRead(t, cache.srcContent.baseDir),
-	}
-
-	logs := reconcileAsAtStartup(t, cache)
-
-	for _, path := range unreadable {
-		assertSkippedEntryWarning(t, logs, path)
-	}
-}
-
 // TestPeriodicReconciliationAdoptsFileThatAppearsAfterStartup proves
 // reconciliation is not a one-shot startup-only pass: it must also run
 // on the periodic ticker, so a variant file that lands on disk with no

internal/imgcache/pendingaccesstimes_internal_test.go

@@ -5,7 +5,6 @@ import (
 	"context"
 	"database/sql"
 	"errors"
-	"image/color"
 	"io"
 	"log/slog"
 	"strings"
@@ -205,8 +204,8 @@ func TestSource_HandsAccessTimeToTheBackgroundWriter(t *testing.T) {
 	t.Parallel()
 
 	cache, _ := newEvictionTestCache(t, 1<<30)
-	content := generateTestJPEG(t, 10, 10, color.RGBA{0, 0, 255, 255})
-	key := storeEvictionTestSource(t, cache, "example.com", "/photo.jpg", content)
+	key := storeEvictionTestSource(t, cache, "example.com", "/photo.jpg",
+		[]byte("source bytes"))
 	anHourAgo := time.Now().Add(-time.Hour)
 	setSourceLastAccessed(t, cache, key, anHourAgo)
 
@@ -225,7 +224,7 @@ func TestSource_HandsAccessTimeToTheBackgroundWriter(t *testing.T) {
 	found, err := io.ReadAll(reader)
 	_ = reader.Close()
 
-	if err != nil || !bytes.Equal(found, content) {
+	if err != nil || string(found) != "source bytes" {
 		t.Fatalf("Source() reads %q, %v; want the source of %q", found, err, key)
 	}
 

internal/imgcache/source_content_internal_test.go

@@ -2,17 +2,12 @@ package imgcache
 
 import (
 	"bytes"
-	"errors"
-	"fmt"
-	"image/color"
 	"io"
 	"os"
 	"path/filepath"
 	"testing"
 
-	"sneak.berlin/go/pixa/internal/imageprocessor"
 	"sneak.berlin/go/pixa/internal/imagerequest"
-	"sneak.berlin/go/pixa/internal/magic"
 )
 
 // TestPutSource_StoresIdenticalBytesOfTwoURLsTwice stores the same bytes
@@ -69,7 +64,7 @@ func TestEvictSourceBlob_LeavesSourceWithIdenticalBytesServed(t *testing.T) {
 	t.Parallel()
 
 	cache, _ := newEvictionTestCache(t, 1<<30)
-	content := generateTestJPEG(t, 20, 20, color.RGBA{0x5B, 0x5B, 0x5B, 255})
+	content := bytes.Repeat([]byte{0x5B}, 400)
 
 	evicted := storeEvictionTestSource(t, cache, testHostCDN, "/evicted.jpg", content)
 	storeEvictionTestSource(t, cache, testHostCDN, "/kept.jpg", content)
@@ -127,7 +122,7 @@ func TestPutSource_FailedRowWriteLeavesNoFile(t *testing.T) {
 	req := &imagerequest.Request{
 		Source: imagerequest.Source{Host: testHostCDN, Path: testPathCat},
 	}
-	key, err := cache.PutSource(t.Context(), req.Source,
+	key, err := cache.PutSource(t.Context(), req.Source, imagerequest.FormatJPEG,
 		bytes.NewReader([]byte("source bytes")))
 	t.Logf("PutSource() = %q, error = %v", key, err)
 
@@ -141,98 +136,36 @@ func TestPutSource_FailedRowWriteLeavesNoFile(t *testing.T) {
 	}
 }
 
-// TestSource_FormatFromFirstBytes stores an image in each source format
-// under one source URL, in turn. After each store, Source must return that
-// image whole, with its format read from the file.
-func TestSource_FormatFromFirstBytes(t *testing.T) {
+// TestSource_ReturnsTheFormatPutSourceStored stores a source as PNG, then
+// the same source URL again as WebP. After each store, Source must return
+// the format that store gave.
+func TestSource_ReturnsTheFormatPutSourceStored(t *testing.T) {
 	t.Parallel()
 
 	cache, _ := newEvictionTestCache(t, 1<<30)
-	processor := imageprocessor.New(imageprocessor.Params{
-		MaxInputBytes:           50 << 20,
-		MaxConcurrentProcessing: 1,
-	})
-	jpegImage := generateTestJPEG(t, 40, 30, color.RGBA{200, 40, 40, 255})
 	src := imagerequest.Source{Host: testHostCDN, Path: testPathCat}
 
 	for _, format := range []imagerequest.Format{
-		imagerequest.FormatJPEG, imagerequest.FormatPNG, imagerequest.FormatGIF,
-		imagerequest.FormatWebP, imagerequest.FormatAVIF, imagerequest.FormatJXL,
+		imagerequest.FormatPNG, imagerequest.FormatWebP,
 	} {
-		result, err := processor.Process(t.Context(), bytes.NewReader(jpegImage),
-			imagerequest.FormatJPEG, &imagerequest.Transform{Format: format})
-		if err != nil {
-			t.Fatalf("making a %s image: %v", format, err)
-		}
-
-		image, err := io.ReadAll(result.Content)
-		if err != nil {
-			t.Fatalf("reading the %s image: %v", format, err)
-		}
-
-		_, err = cache.PutSource(t.Context(), src, bytes.NewReader(image))
+		_, err := cache.PutSource(t.Context(), src, format,
+			bytes.NewReader([]byte("source bytes")))
 		if err != nil {
 			t.Fatalf("PutSource(%s) error = %v", format, err)
 		}
 
-		reader, size, got, err := cache.Source(t.Context(), src)
+		reader, _, got, err := cache.Source(t.Context(), src)
 		if err != nil {
-			t.Fatalf("Source() of the %s image error = %v", format, err)
+			t.Fatalf("Source() after PutSource(%s) error = %v", format, err)
 		}
 
-		served, err := io.ReadAll(reader)
 		_ = reader.Close()
 
-		if err != nil {
-			t.Fatalf("reading the %s source: %v", format, err)
-		}
-
-		t.Logf("%s: %d bytes read as %s", format, size, got)
+		t.Logf("Source() after PutSource(%s): format %s", format, got)
 
 		if got != format {
-			t.Errorf("Source() of the %s image format = %q, want %q",
+			t.Errorf("Source() after PutSource(%s) format = %q, want %q",
 				format, got, format)
 		}
-
-		if size != int64(len(image)) || !bytes.Equal(served, image) {
-			t.Errorf("%s source read as %d bytes, size %d, want the %d bytes stored",
-				format, len(served), size, len(image))
-		}
-	}
-}
-
-// TestSource_RefusesFileOfNoSourceFormat checks that Source refuses a
-// cached source whose file's first bytes are not those of a source format,
-// with an error other than ErrNotFound.
-func TestSource_RefusesFileOfNoSourceFormat(t *testing.T) {
-	t.Parallel()
-
-	cache, _ := newEvictionTestCache(t, 1<<30)
-	jpegImage := generateTestJPEG(t, 10, 10, color.RGBA{0, 0, 255, 255})
-
-	tests := []struct {
-		name    string
-		content []byte
-		wantErr error
-	}{
-		{"text", []byte("this is text, not an image"), magic.ErrUnknownFormat},
-		{"SVG", []byte(`<svg xmlns="http://www.w3.org/2000/svg"></svg>`),
-			magic.ErrUnknownFormat},
-		{"JPEG cut to 10 bytes", jpegImage[:10], io.EOF},
-		{"empty file", nil, io.EOF},
-	}
-
-	for i, tt := range tests {
-		path := fmt.Sprintf("/refused%d.jpg", i)
-		storeEvictionTestSource(t, cache, testHostCDN, path, tt.content)
-
-		reader, _, format, err := cache.Source(t.Context(),
-			imagerequest.Source{Host: testHostCDN, Path: path})
-		t.Logf("%s: Source() error = %v", tt.name, err)
-
-		if reader != nil || format != "" || !errors.Is(err, tt.wantErr) {
-			t.Errorf("%s: Source() = reader %v, format %q, error %v; "+
-				"want no reader and %v", tt.name, reader, format, err, tt.wantErr)
-		}
 	}
 }