refactor: use Params struct for imageprocessor constructor

Rename NewImageProcessor(maxInputBytes) to New(Params{}) with a Params
struct containing MaxInputBytes. Zero-value Params{} uses sensible
defaults (DefaultMaxInputBytes). All callers updated.

Addresses review feedback on PR #37.

.dockerignore

@@ -6,4 +6,3 @@
 node_modules
 bin/
 data/
-deploy/

Dockerfile

@@ -75,7 +75,4 @@ WORKDIR /var/lib/pixa
 
 EXPOSE 8080
 
-HEALTHCHECK --interval=30s --timeout=5s --start-period=10s --retries=3 \
-    CMD wget -q --spider http://localhost:8080/.well-known/healthcheck.json
-
 ENTRYPOINT ["/usr/local/bin/pixad", "--config", "/etc/pixa/config.yml"]

README.md

@@ -125,17 +125,6 @@ See `config.example.yml` for all options with defaults.
 - **Metrics**: Prometheus
 - **Logging**: stdlib slog
 
-## Deployment
-
-Pixa is deployed via
-[µPaaS](https://git.eeqj.de/sneak/upaas) on `fsn1app1`
-(paas.datavi.be). Pushes to `main` trigger automatic builds and
-deployments. The Dockerfile includes a `HEALTHCHECK` that probes
-`/.well-known/healthcheck.json`.
-
-See [deploy/README.md](deploy/README.md) for the full µPaaS app
-configuration, volume mounts, and production setup instructions.
-
 ## TODO
 
 See [TODO.md](TODO.md) for the full prioritized task list.

deploy/README.md

@@ -1,78 +0,0 @@
-# Pixa Deployment via µPaaS
-
-Pixa is deployed on `fsn1app1` via
-[µPaaS](https://git.eeqj.de/sneak/upaas) (paas.datavi.be).
-
-## µPaaS App Configuration
-
-Create the app in the µPaaS web UI with these settings:
-
-| Setting | Value |
-| --- | --- |
-| **App name** | `pixa` |
-| **Repo URL** | `git@git.eeqj.de:sneak/pixa.git` |
-| **Branch** | `main` |
-| **Dockerfile path** | `Dockerfile` |
-
-### Environment Variables
-
-| Variable | Description | Required |
-| --- | --- | --- |
-| `PORT` | HTTP listen port (default: 8080) | No |
-
-Configuration is provided via the config file baked into the Docker
-image at `/etc/pixa/config.yml`. To override it, mount a custom
-config file as a volume (see below).
-
-### Volumes
-
-| Host Path | Container Path | Description |
-| --- | --- | --- |
-| `/srv/pixa/data` | `/var/lib/pixa` | SQLite database and image cache |
-| `/srv/pixa/config.yml` | `/etc/pixa/config.yml` | Production config (signing key, whitelist, etc.) |
-
-### Ports
-
-| Host Port | Container Port | Protocol |
-| --- | --- | --- |
-| (assigned) | 8080 | TCP |
-
-### Docker Network
-
-Attach to the shared reverse-proxy network if using Caddy/Traefik
-for TLS termination.
-
-## Production Configuration
-
-Copy `config.example.yml` from the repo root and customize for
-production:
-
-```yaml
-port: 8080
-debug: false
-maintenance_mode: false
-state_dir: /var/lib/pixa
-signing_key: "<generate with: openssl rand -base64 32>"
-whitelist_hosts:
-    - s3.sneak.cloud
-    - static.sneak.cloud
-    - sneak.berlin
-allow_http: false
-```
-
-**Important:** Generate a unique `signing_key` for production. Never
-use the default placeholder value.
-
-## Health Check
-
-The Dockerfile includes a `HEALTHCHECK` instruction that probes
-`/.well-known/healthcheck.json` every 30 seconds. µPaaS verifies
-container health 60 seconds after deployment.
-
-## Deployment Flow
-
-1. Push to `main` triggers the Gitea webhook
-2. µPaaS clones the repo and runs `docker build .`
-3. The Dockerfile runs `make check` (format, lint, test) during build
-4. On success, µPaaS stops the old container and starts the new one
-5. After 60 seconds, µPaaS checks container health

internal/database/database.go

@@ -35,6 +35,41 @@ type Database struct {
 	config *config.Config
 }
 
+// ParseMigrationVersion extracts the numeric version prefix from a migration
+// filename. Filenames must follow the pattern "<version>.sql" or
+// "<version>_<description>.sql", where version is a zero-padded numeric
+// string (e.g. "001", "002"). Returns the version string and an error if
+// the filename does not match the expected pattern.
+func ParseMigrationVersion(filename string) (string, error) {
+	name := strings.TrimSuffix(filename, filepath.Ext(filename))
+	if name == "" {
+		return "", fmt.Errorf("invalid migration filename %q: empty name", filename)
+	}
+
+	// Split on underscore to separate version from description.
+	// If there's no underscore, the entire stem is the version.
+	version := name
+	if idx := strings.IndexByte(name, '_'); idx >= 0 {
+		version = name[:idx]
+	}
+
+	if version == "" {
+		return "", fmt.Errorf("invalid migration filename %q: empty version prefix", filename)
+	}
+
+	// Validate the version is purely numeric.
+	for _, ch := range version {
+		if ch < '0' || ch > '9' {
+			return "", fmt.Errorf(
+				"invalid migration filename %q: version %q contains non-numeric character %q",
+				filename, version, string(ch),
+			)
+		}
+	}
+
+	return version, nil
+}
+
 // New creates a new Database instance.
 func New(lc fx.Lifecycle, params Params) (*Database, error) {
 	s := &Database{
@@ -84,96 +119,33 @@ func (s *Database) connect(ctx context.Context) error {
 	s.db = db
 	s.log.Info("database connected")
 
-	return s.runMigrations(ctx)
+	return ApplyMigrations(ctx, s.db, s.log)
 }
 
-func (s *Database) runMigrations(ctx context.Context) error {
+// collectMigrations reads the embedded schema directory and returns
-	// Create migrations tracking table
+// migration filenames sorted lexicographically.
-	_, err := s.db.ExecContext(ctx, `
+func collectMigrations() ([]string, error) {
-		CREATE TABLE IF NOT EXISTS schema_migrations (
-			version TEXT PRIMARY KEY,
-			applied_at DATETIME DEFAULT CURRENT_TIMESTAMP
-		)
-	`)
-	if err != nil {
-		return fmt.Errorf("failed to create migrations table: %w", err)
-	}
-
-	// Get list of migration files
 	entries, err := schemaFS.ReadDir("schema")
 	if err != nil {
-		return fmt.Errorf("failed to read schema directory: %w", err)
+		return nil, fmt.Errorf("failed to read schema directory: %w", err)
 	}
 
-	// Sort migration files by name (001.sql, 002.sql, etc.)
 	var migrations []string
+
 	for _, entry := range entries {
 		if !entry.IsDir() && strings.HasSuffix(entry.Name(), ".sql") {
 			migrations = append(migrations, entry.Name())
 		}
 	}
+
 	sort.Strings(migrations)
 
-	// Apply each migration that hasn't been applied yet
+	return migrations, nil
-	for _, migration := range migrations {
-		version := strings.TrimSuffix(migration, filepath.Ext(migration))
-
-		// Check if already applied
-		var count int
-		err := s.db.QueryRowContext(ctx,
-			"SELECT COUNT(*) FROM schema_migrations WHERE version = ?",
-			version,
-		).Scan(&count)
-		if err != nil {
-			return fmt.Errorf("failed to check migration status: %w", err)
 }
 
-		if count > 0 {
+// ensureMigrationsTable creates the schema_migrations tracking table if
-			s.log.Debug("migration already applied", "version", version)
+// it does not already exist.
-
+func ensureMigrationsTable(ctx context.Context, db *sql.DB) error {
-			continue
-		}
-
-		// Read and apply migration
-		content, err := schemaFS.ReadFile(filepath.Join("schema", migration))
-		if err != nil {
-			return fmt.Errorf("failed to read migration %s: %w", migration, err)
-		}
-
-		s.log.Info("applying migration", "version", version)
-
-		_, err = s.db.ExecContext(ctx, string(content))
-		if err != nil {
-			return fmt.Errorf("failed to apply migration %s: %w", migration, err)
-		}
-
-		// Record migration as applied
-		_, err = s.db.ExecContext(ctx,
-			"INSERT INTO schema_migrations (version) VALUES (?)",
-			version,
-		)
-		if err != nil {
-			return fmt.Errorf("failed to record migration %s: %w", migration, err)
-		}
-
-		s.log.Info("migration applied successfully", "version", version)
-	}
-
-	return nil
-}
-
-// DB returns the underlying sql.DB.
-func (s *Database) DB() *sql.DB {
-	return s.db
-}
-
-// ApplyMigrations applies all migrations to the given database.
-// This is useful for testing where you want to use the real schema
-// without the full fx lifecycle.
-func ApplyMigrations(db *sql.DB) error {
-	ctx := context.Background()
-
-	// Create migrations tracking table
 	_, err := db.ExecContext(ctx, `
 		CREATE TABLE IF NOT EXISTS schema_migrations (
 			version TEXT PRIMARY KEY,
@@ -184,27 +156,32 @@ func ApplyMigrations(db *sql.DB) error {
 		return fmt.Errorf("failed to create migrations table: %w", err)
 	}
 
-	// Get list of migration files
+	return nil
-	entries, err := schemaFS.ReadDir("schema")
+}
+
+// ApplyMigrations applies all pending migrations to db. An optional logger
+// may be provided for informational output; pass nil for silent operation.
+// This is exported so tests can apply the real schema without the full fx
+// lifecycle.
+func ApplyMigrations(ctx context.Context, db *sql.DB, log *slog.Logger) error {
+	if err := ensureMigrationsTable(ctx, db); err != nil {
+		return err
+	}
+
+	migrations, err := collectMigrations()
 	if err != nil {
-		return fmt.Errorf("failed to read schema directory: %w", err)
+		return err
 	}
 
-	// Sort migration files by name (001.sql, 002.sql, etc.)
-	var migrations []string
-	for _, entry := range entries {
-		if !entry.IsDir() && strings.HasSuffix(entry.Name(), ".sql") {
-			migrations = append(migrations, entry.Name())
-		}
-	}
-	sort.Strings(migrations)
-
-	// Apply each migration that hasn't been applied yet
 	for _, migration := range migrations {
-		version := strings.TrimSuffix(migration, filepath.Ext(migration))
+		version, parseErr := ParseMigrationVersion(migration)
+		if parseErr != nil {
+			return parseErr
+		}
 
-		// Check if already applied
+		// Check if already applied.
 		var count int
+
 		err := db.QueryRowContext(ctx,
 			"SELECT COUNT(*) FROM schema_migrations WHERE version = ?",
 			version,
@@ -214,29 +191,46 @@ func ApplyMigrations(db *sql.DB) error {
 		}
 
 		if count > 0 {
+			if log != nil {
+				log.Debug("migration already applied", "version", version)
+			}
+
 			continue
 		}
 
-		// Read and apply migration
+		// Read and apply migration.
-		content, err := schemaFS.ReadFile(filepath.Join("schema", migration))
+		content, readErr := schemaFS.ReadFile(filepath.Join("schema", migration))
-		if err != nil {
+		if readErr != nil {
-			return fmt.Errorf("failed to read migration %s: %w", migration, err)
+			return fmt.Errorf("failed to read migration %s: %w", migration, readErr)
 		}
 
-		_, err = db.ExecContext(ctx, string(content))
+		if log != nil {
-		if err != nil {
+			log.Info("applying migration", "version", version)
-			return fmt.Errorf("failed to apply migration %s: %w", migration, err)
 		}
 
-		// Record migration as applied
+		_, execErr := db.ExecContext(ctx, string(content))
-		_, err = db.ExecContext(ctx,
+		if execErr != nil {
+			return fmt.Errorf("failed to apply migration %s: %w", migration, execErr)
+		}
+
+		// Record migration as applied.
+		_, recErr := db.ExecContext(ctx,
 			"INSERT INTO schema_migrations (version) VALUES (?)",
 			version,
 		)
-		if err != nil {
+		if recErr != nil {
-			return fmt.Errorf("failed to record migration %s: %w", migration, err)
+			return fmt.Errorf("failed to record migration %s: %w", migration, recErr)
+		}
+
+		if log != nil {
+			log.Info("migration applied successfully", "version", version)
 		}
 	}
 
 	return nil
 }
+
+// DB returns the underlying sql.DB.
+func (s *Database) DB() *sql.DB {
+	return s.db
+}

internal/database/database_test.go

@@ -0,0 +1,155 @@
+package database
+
+import (
+	"context"
+	"database/sql"
+	"testing"
+
+	_ "modernc.org/sqlite" // SQLite driver registration
+)
+
+func TestParseMigrationVersion(t *testing.T) {
+	tests := []struct {
+		name     string
+		filename string
+		want     string
+		wantErr  bool
+	}{
+		{
+			name:     "version only",
+			filename: "001.sql",
+			want:     "001",
+		},
+		{
+			name:     "version with description",
+			filename: "001_initial_schema.sql",
+			want:     "001",
+		},
+		{
+			name:     "multi-digit version",
+			filename: "042_add_indexes.sql",
+			want:     "042",
+		},
+		{
+			name:     "long version number",
+			filename: "00001_long_prefix.sql",
+			want:     "00001",
+		},
+		{
+			name:     "description with multiple underscores",
+			filename: "003_add_user_auth_tables.sql",
+			want:     "003",
+		},
+		{
+			name:     "empty filename",
+			filename: ".sql",
+			wantErr:  true,
+		},
+		{
+			name:     "leading underscore",
+			filename: "_description.sql",
+			wantErr:  true,
+		},
+		{
+			name:     "non-numeric version",
+			filename: "abc_migration.sql",
+			wantErr:  true,
+		},
+		{
+			name:     "mixed alphanumeric version",
+			filename: "001a_migration.sql",
+			wantErr:  true,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got, err := ParseMigrationVersion(tt.filename)
+			if tt.wantErr {
+				if err == nil {
+					t.Errorf("ParseMigrationVersion(%q) expected error, got %q", tt.filename, got)
+				}
+
+				return
+			}
+
+			if err != nil {
+				t.Errorf("ParseMigrationVersion(%q) unexpected error: %v", tt.filename, err)
+
+				return
+			}
+
+			if got != tt.want {
+				t.Errorf("ParseMigrationVersion(%q) = %q, want %q", tt.filename, got, tt.want)
+			}
+		})
+	}
+}
+
+func TestApplyMigrations(t *testing.T) {
+	db, err := sql.Open("sqlite", ":memory:")
+	if err != nil {
+		t.Fatalf("failed to open in-memory database: %v", err)
+	}
+	defer db.Close()
+
+	// Apply migrations should succeed.
+	if err := ApplyMigrations(context.Background(), db, nil); err != nil {
+		t.Fatalf("ApplyMigrations failed: %v", err)
+	}
+
+	// Verify the schema_migrations table recorded the version.
+	var version string
+
+	err = db.QueryRowContext(context.Background(),
+		"SELECT version FROM schema_migrations LIMIT 1",
+	).Scan(&version)
+	if err != nil {
+		t.Fatalf("failed to query schema_migrations: %v", err)
+	}
+
+	if version != "001" {
+		t.Errorf("expected version %q, got %q", "001", version)
+	}
+
+	// Verify a table from the migration exists (source_content).
+	var tableName string
+
+	err = db.QueryRowContext(context.Background(),
+		"SELECT name FROM sqlite_master WHERE type='table' AND name='source_content'",
+	).Scan(&tableName)
+	if err != nil {
+		t.Fatalf("expected source_content table to exist: %v", err)
+	}
+}
+
+func TestApplyMigrationsIdempotent(t *testing.T) {
+	db, err := sql.Open("sqlite", ":memory:")
+	if err != nil {
+		t.Fatalf("failed to open in-memory database: %v", err)
+	}
+	defer db.Close()
+
+	// Apply twice should succeed (idempotent).
+	if err := ApplyMigrations(context.Background(), db, nil); err != nil {
+		t.Fatalf("first ApplyMigrations failed: %v", err)
+	}
+
+	if err := ApplyMigrations(context.Background(), db, nil); err != nil {
+		t.Fatalf("second ApplyMigrations failed: %v", err)
+	}
+
+	// Should still have exactly one migration recorded.
+	var count int
+
+	err = db.QueryRowContext(context.Background(),
+		"SELECT COUNT(*) FROM schema_migrations",
+	).Scan(&count)
+	if err != nil {
+		t.Fatalf("failed to count schema_migrations: %v", err)
+	}
+
+	if count != 1 {
+		t.Errorf("expected 1 migration record, got %d", count)
+	}
+}

internal/handlers/handlers_test.go

@@ -82,7 +82,7 @@ func setupTestDB(t *testing.T) *sql.DB {
 		t.Fatalf("failed to open test db: %v", err)
 	}
 
-	if err := database.ApplyMigrations(db); err != nil {
+	if err := database.ApplyMigrations(context.Background(), db, nil); err != nil {
 		t.Fatalf("failed to apply migrations: %v", err)
 	}
 

internal/imgcache/processor.go

@@ -26,20 +26,45 @@ func initVips() {
 // Images larger than this are rejected to prevent DoS via decompression bombs.
 const MaxInputDimension = 8192
 
+// DefaultMaxInputBytes is the default maximum input size in bytes (50 MiB).
+// This matches the default upstream fetcher limit.
+const DefaultMaxInputBytes = 50 << 20
+
 // ErrInputTooLarge is returned when input image dimensions exceed MaxInputDimension.
 var ErrInputTooLarge = errors.New("input image dimensions exceed maximum")
 
+// ErrInputDataTooLarge is returned when the raw input data exceeds the configured byte limit.
+var ErrInputDataTooLarge = errors.New("input data exceeds maximum allowed size")
+
 // ErrUnsupportedOutputFormat is returned when the requested output format is not supported.
 var ErrUnsupportedOutputFormat = errors.New("unsupported output format")
 
 // ImageProcessor implements the Processor interface using libvips via govips.
-type ImageProcessor struct{}
+type ImageProcessor struct {
+	maxInputBytes int64
+}
 
-// NewImageProcessor creates a new image processor.
+// Params holds configuration for creating an ImageProcessor.
-func NewImageProcessor() *ImageProcessor {
+// Zero values use sensible defaults (MaxInputBytes defaults to DefaultMaxInputBytes).
+type Params struct {
+	// MaxInputBytes is the maximum allowed input size in bytes.
+	// If <= 0, DefaultMaxInputBytes is used.
+	MaxInputBytes int64
+}
+
+// New creates a new image processor with the given parameters.
+// A zero-value Params{} uses sensible defaults.
+func New(params Params) *ImageProcessor {
 	initVips()
 
-	return &ImageProcessor{}
+	maxInputBytes := params.MaxInputBytes
+	if maxInputBytes <= 0 {
+		maxInputBytes = DefaultMaxInputBytes
+	}
+
+	return &ImageProcessor{
+		maxInputBytes: maxInputBytes,
+	}
 }
 
 // Process transforms an image according to the request.
@@ -48,12 +73,20 @@ func (p *ImageProcessor) Process(
 	input io.Reader,
 	req *ImageRequest,
 ) (*ProcessResult, error) {
-	// Read input
+	// Read input with a size limit to prevent unbounded memory consumption.
-	data, err := io.ReadAll(input)
+	// We read at most maxInputBytes+1 so we can detect if the input exceeds
+	// the limit without consuming additional memory.
+	limited := io.LimitReader(input, p.maxInputBytes+1)
+
+	data, err := io.ReadAll(limited)
 	if err != nil {
 		return nil, fmt.Errorf("failed to read input: %w", err)
 	}
 
+	if int64(len(data)) > p.maxInputBytes {
+		return nil, ErrInputDataTooLarge
+	}
+
 	// Decode image
 	img, err := vips.NewImageFromBuffer(data)
 	if err != nil {

internal/imgcache/processor_test.go

@@ -71,7 +71,7 @@ func createTestPNG(t *testing.T, width, height int) []byte {
 }
 
 func TestImageProcessor_ResizeJPEG(t *testing.T) {
-	proc := NewImageProcessor()
+	proc := New(Params{})
 	ctx := context.Background()
 
 	input := createTestJPEG(t, 800, 600)
@@ -118,7 +118,7 @@ func TestImageProcessor_ResizeJPEG(t *testing.T) {
 }
 
 func TestImageProcessor_ConvertToPNG(t *testing.T) {
-	proc := NewImageProcessor()
+	proc := New(Params{})
 	ctx := context.Background()
 
 	input := createTestJPEG(t, 200, 150)
@@ -151,7 +151,7 @@ func TestImageProcessor_ConvertToPNG(t *testing.T) {
 }
 
 func TestImageProcessor_OriginalSize(t *testing.T) {
-	proc := NewImageProcessor()
+	proc := New(Params{})
 	ctx := context.Background()
 
 	input := createTestJPEG(t, 640, 480)
@@ -179,7 +179,7 @@ func TestImageProcessor_OriginalSize(t *testing.T) {
 }
 
 func TestImageProcessor_FitContain(t *testing.T) {
-	proc := NewImageProcessor()
+	proc := New(Params{})
 	ctx := context.Background()
 
 	// 800x400 image (2:1 aspect) into 400x400 box with contain
@@ -206,7 +206,7 @@ func TestImageProcessor_FitContain(t *testing.T) {
 }
 
 func TestImageProcessor_ProportionalScale_WidthOnly(t *testing.T) {
-	proc := NewImageProcessor()
+	proc := New(Params{})
 	ctx := context.Background()
 
 	// 800x600 image, request width=400 height=0
@@ -236,7 +236,7 @@ func TestImageProcessor_ProportionalScale_WidthOnly(t *testing.T) {
 }
 
 func TestImageProcessor_ProportionalScale_HeightOnly(t *testing.T) {
-	proc := NewImageProcessor()
+	proc := New(Params{})
 	ctx := context.Background()
 
 	// 800x600 image, request width=0 height=300
@@ -266,7 +266,7 @@ func TestImageProcessor_ProportionalScale_HeightOnly(t *testing.T) {
 }
 
 func TestImageProcessor_ProcessPNG(t *testing.T) {
-	proc := NewImageProcessor()
+	proc := New(Params{})
 	ctx := context.Background()
 
 	input := createTestPNG(t, 400, 300)
@@ -298,7 +298,7 @@ func TestImageProcessor_ImplementsInterface(t *testing.T) {
 }
 
 func TestImageProcessor_SupportedFormats(t *testing.T) {
-	proc := NewImageProcessor()
+	proc := New(Params{})
 
 	inputFormats := proc.SupportedInputFormats()
 	if len(inputFormats) == 0 {
@@ -312,7 +312,7 @@ func TestImageProcessor_SupportedFormats(t *testing.T) {
 }
 
 func TestImageProcessor_RejectsOversizedInput(t *testing.T) {
-	proc := NewImageProcessor()
+	proc := New(Params{})
 	ctx := context.Background()
 
 	// Create an image that exceeds MaxInputDimension (e.g., 10000x100)
@@ -337,7 +337,7 @@ func TestImageProcessor_RejectsOversizedInput(t *testing.T) {
 }
 
 func TestImageProcessor_RejectsOversizedInputHeight(t *testing.T) {
-	proc := NewImageProcessor()
+	proc := New(Params{})
 	ctx := context.Background()
 
 	// Create an image with oversized height
@@ -361,7 +361,7 @@ func TestImageProcessor_RejectsOversizedInputHeight(t *testing.T) {
 }
 
 func TestImageProcessor_AcceptsMaxDimensionInput(t *testing.T) {
-	proc := NewImageProcessor()
+	proc := New(Params{})
 	ctx := context.Background()
 
 	// Create an image at exactly MaxInputDimension - should be accepted
@@ -383,7 +383,7 @@ func TestImageProcessor_AcceptsMaxDimensionInput(t *testing.T) {
 }
 
 func TestImageProcessor_EncodeWebP(t *testing.T) {
-	proc := NewImageProcessor()
+	proc := New(Params{})
 	ctx := context.Background()
 
 	input := createTestJPEG(t, 200, 150)
@@ -426,7 +426,7 @@ func TestImageProcessor_EncodeWebP(t *testing.T) {
 }
 
 func TestImageProcessor_DecodeAVIF(t *testing.T) {
-	proc := NewImageProcessor()
+	proc := New(Params{})
 	ctx := context.Background()
 
 	// Load test AVIF file
@@ -465,8 +465,73 @@ func TestImageProcessor_DecodeAVIF(t *testing.T) {
 	}
 }
 
+func TestImageProcessor_RejectsOversizedInputData(t *testing.T) {
+	// Create a processor with a very small byte limit
+	const limit = 1024
+	proc := New(Params{MaxInputBytes: limit})
+	ctx := context.Background()
+
+	// Create a valid JPEG that exceeds the byte limit
+	input := createTestJPEG(t, 800, 600) // will be well over 1 KiB
+	if int64(len(input)) <= limit {
+		t.Fatalf("test JPEG must exceed %d bytes, got %d", limit, len(input))
+	}
+
+	req := &ImageRequest{
+		Size:    Size{Width: 100, Height: 75},
+		Format:  FormatJPEG,
+		Quality: 85,
+		FitMode: FitCover,
+	}
+
+	_, err := proc.Process(ctx, bytes.NewReader(input), req)
+	if err == nil {
+		t.Fatal("Process() should reject input exceeding maxInputBytes")
+	}
+
+	if err != ErrInputDataTooLarge {
+		t.Errorf("Process() error = %v, want ErrInputDataTooLarge", err)
+	}
+}
+
+func TestImageProcessor_AcceptsInputWithinLimit(t *testing.T) {
+	// Create a small image and set limit well above its size
+	input := createTestJPEG(t, 10, 10)
+	limit := int64(len(input)) * 10 // 10× headroom
+
+	proc := New(Params{MaxInputBytes: limit})
+	ctx := context.Background()
+
+	req := &ImageRequest{
+		Size:    Size{Width: 10, Height: 10},
+		Format:  FormatJPEG,
+		Quality: 85,
+		FitMode: FitCover,
+	}
+
+	result, err := proc.Process(ctx, bytes.NewReader(input), req)
+	if err != nil {
+		t.Fatalf("Process() error = %v, want nil", err)
+	}
+	defer result.Content.Close()
+}
+
+func TestImageProcessor_DefaultMaxInputBytes(t *testing.T) {
+	// Passing 0 should use the default
+	proc := New(Params{})
+	if proc.maxInputBytes != DefaultMaxInputBytes {
+		t.Errorf("maxInputBytes = %d, want %d", proc.maxInputBytes, DefaultMaxInputBytes)
+	}
+
+	// Passing negative should also use the default
+	proc = New(Params{MaxInputBytes: -1})
+	if proc.maxInputBytes != DefaultMaxInputBytes {
+		t.Errorf("maxInputBytes = %d, want %d", proc.maxInputBytes, DefaultMaxInputBytes)
+	}
+}
+
 func TestImageProcessor_EncodeAVIF(t *testing.T) {
-	proc := NewImageProcessor()
+	proc := New(Params{})
 	ctx := context.Background()
 
 	input := createTestJPEG(t, 200, 150)

internal/imgcache/service.go

@@ -22,6 +22,7 @@ type Service struct {
 	whitelist       *HostWhitelist
 	log             *slog.Logger
 	allowHTTP       bool
+	maxResponseSize int64
 }
 
 // ServiceConfig holds configuration for the image service.
@@ -50,15 +51,17 @@ func NewService(cfg *ServiceConfig) (*Service, error) {
 		return nil, errors.New("signing key is required")
 	}
 
+	// Resolve fetcher config for defaults
+	fetcherCfg := cfg.FetcherConfig
+	if fetcherCfg == nil {
+		fetcherCfg = DefaultFetcherConfig()
+	}
+
 	// Use custom fetcher if provided, otherwise create HTTP fetcher
 	var fetcher Fetcher
 	if cfg.Fetcher != nil {
 		fetcher = cfg.Fetcher
 	} else {
-		fetcherCfg := cfg.FetcherConfig
-		if fetcherCfg == nil {
-			fetcherCfg = DefaultFetcherConfig()
-		}
 		fetcher = NewHTTPFetcher(fetcherCfg)
 	}
 
@@ -74,14 +77,17 @@ func NewService(cfg *ServiceConfig) (*Service, error) {
 		allowHTTP = cfg.FetcherConfig.AllowHTTP
 	}
 
+	maxResponseSize := fetcherCfg.MaxResponseSize
+
 	return &Service{
 		cache:           cfg.Cache,
 		fetcher:         fetcher,
-		processor: NewImageProcessor(),
+		processor:       New(Params{MaxInputBytes: maxResponseSize}),
 		signer:          signer,
 		whitelist:       NewHostWhitelist(cfg.Whitelist),
 		log:             log,
 		allowHTTP:       allowHTTP,
+		maxResponseSize: maxResponseSize,
 	}, nil
 }
 
@@ -146,6 +152,40 @@ func (s *Service) Get(ctx context.Context, req *ImageRequest) (*ImageResponse, e
 	return response, nil
 }
 
+// loadCachedSource attempts to load source content from cache, returning nil
+// if the cached data is unavailable or exceeds maxResponseSize.
+func (s *Service) loadCachedSource(contentHash ContentHash) []byte {
+	reader, err := s.cache.GetSourceContent(contentHash)
+	if err != nil {
+		s.log.Warn("failed to load cached source, fetching", "error", err)
+
+		return nil
+	}
+
+	// Bound the read to maxResponseSize to prevent unbounded memory use
+	// from unexpectedly large cached files.
+	limited := io.LimitReader(reader, s.maxResponseSize+1)
+	data, err := io.ReadAll(limited)
+	_ = reader.Close()
+
+	if err != nil {
+		s.log.Warn("failed to read cached source, fetching", "error", err)
+
+		return nil
+	}
+
+	if int64(len(data)) > s.maxResponseSize {
+		s.log.Warn("cached source exceeds max response size, discarding",
+			"hash", contentHash,
+			"max_bytes", s.maxResponseSize,
+		)
+
+		return nil
+	}
+
+	return data
+}
+
 // processFromSourceOrFetch processes an image, using cached source content if available.
 func (s *Service) processFromSourceOrFetch(
 	ctx context.Context,
@@ -162,22 +202,8 @@ func (s *Service) processFromSourceOrFetch(
 	var fetchBytes int64
 
 	if contentHash != "" {
-		// We have cached source - load it
 		s.log.Debug("using cached source", "hash", contentHash)
-
+		sourceData = s.loadCachedSource(contentHash)
-		reader, err := s.cache.GetSourceContent(contentHash)
-		if err != nil {
-			s.log.Warn("failed to load cached source, fetching", "error", err)
-			// Fall through to fetch
-		} else {
-			sourceData, err = io.ReadAll(reader)
-			_ = reader.Close()
-
-			if err != nil {
-				s.log.Warn("failed to read cached source, fetching", "error", err)
-				// Fall through to fetch
-			}
-		}
 	}
 
 	// Fetch from upstream if we don't have source data or it's empty

internal/imgcache/stats_test.go

@@ -16,7 +16,7 @@ func setupStatsTestDB(t *testing.T) *sql.DB {
 	if err != nil {
 		t.Fatal(err)
 	}
-	if err := database.ApplyMigrations(db); err != nil {
+	if err := database.ApplyMigrations(context.Background(), db, nil); err != nil {
 		t.Fatal(err)
 	}
 	t.Cleanup(func() { db.Close() })

internal/imgcache/testutil_test.go

@@ -2,6 +2,7 @@ package imgcache
 
 import (
 	"bytes"
+	"context"
 	"database/sql"
 	"image"
 	"image/color"
@@ -193,7 +194,7 @@ func setupServiceTestDB(t *testing.T) *sql.DB {
 	}
 
 	// Use the real production schema via migrations
-	if err := database.ApplyMigrations(db); err != nil {
+	if err := database.ApplyMigrations(context.Background(), db, nil); err != nil {
 		t.Fatalf("failed to apply migrations: %v", err)
 	}