Fail loudly on set-but-unparseable env config values (closes #80)

The config env helpers silently substituted the documented default
whenever a variable was set but could not be parsed, so a typo in an
operator-supplied value produced a running daemon with configuration
nobody asked for instead of a startup failure. `PORT=eighty` quietly
listened on 8080 and `DEBUG=ture` quietly disabled debug logging.

Defaults now apply only to variables that are unset or empty. Any
variable that is set but unparseable is a hard error that names the
key and the offending value and aborts startup through fx.

- add `envPositiveInt` with `ErrNonPositiveValue`, copied verbatim
  from the definition on the unmerged #87 so that rebasing after it
  lands is a delete-one-copy operation rather than a semantic merge
- remove `envInt` entirely; `PORT` is parsed by a new `envPort`,
  which adds the TCP upper bound (`ErrInvalidPort`, 1..65535)
- change `envBool` to return an error and parse with
  `strconv.ParseBool`, so `yes`, `on`, and typos are rejected rather
  than silently treated as false; callers are `DEBUG` and
  `MAINTENANCE_MODE`
- move env loading into `loadFromEnv`, with the environment check
  extracted to `resolveEnvironment` (also as #87 defines it), keeping
  `New` within the funlen budget

`envString` parses nothing and `envDuration` was already fail-loud,
so both are unchanged. A repo-wide audit of `os.Getenv`/`os.LookupEnv`
found no parse sites outside `internal/config`.

Tests cover each helper with a table (unset, valid, set-but-invalid)
plus `config.New`-level cases proving a bad `PORT`, `DEBUG`, or
`MAINTENANCE_MODE` aborts startup while unset variables still get
their defaults. README documents the fail-loud rule and the accepted
boolean spellings.

README.md

@@ -89,30 +89,26 @@ TTY detection, and security headers are always applied.
 | `PORT`                  | HTTP listen port                    | `8080`   |
 | `DATA_DIR`              | Directory for all SQLite databases  | `/var/lib/webhooker` |
 | `DEBUG`                 | Enable debug logging                | `false`  |
+| `MAINTENANCE_MODE`      | Serve the maintenance page          | `false`  |
 | `METRICS_USERNAME`      | Basic auth username for `/metrics`  | `""`     |
 | `METRICS_PASSWORD`      | Basic auth password for `/metrics`  | `""`     |
 | `SENTRY_DSN`            | Sentry error reporting DSN          | `""`     |
-| `SESSION_IDLE_TIMEOUT`  | Idle session timeout (Go duration)  | `24h`    |
 
-Sessions are bounded by two independent clocks, and end at whichever
-one runs out first:
+#### Invalid values abort startup
 
-- **Idle expiry** (`SESSION_IDLE_TIMEOUT`, default `24h`) is a sliding
-  window. Every authenticated request pushes it forward, so a session
-  in continuous use never hits it, while an abandoned one expires a day
-  after its last use. Set it to `0` to disable idle expiry entirely;
-  the absolute cap below still applies. A set-but-unparseable value
-  aborts startup rather than silently falling back to the default.
-- **Absolute expiry** is a fixed 7 days from login. Activity does
-  **not** extend it: after a week, every session ends and the user
-  authenticates again.
+The defaults above apply **only** to variables that are unset (or set
+to an empty string). A variable that is set but cannot be parsed is a
+fatal configuration error: webhooker logs the offending variable and
+its value and refuses to start, rather than silently running with a
+substituted default. `PORT=eighty`, `DEBUG=ture`, and
+`RETENTION_SWEEP_INTERVAL=1 hour` all abort startup. `PORT` must
+additionally be a number in the range 1–65535.
 
-Only requests that authenticate with the session count as activity, so
-an unauthenticated request carrying the cookie cannot keep a session
-alive. The idle timestamp is rewritten at most once per tenth of the
-idle window rather than on every request, which means a session may
-expire up to 10% early relative to the user's true last request, but
-never late.
+Boolean variables (`DEBUG`, `MAINTENANCE_MODE`) accept exactly the
+spellings Go's `strconv.ParseBool` accepts — `1`, `t`, `T`, `TRUE`,
+`true`, `True`, `0`, `f`, `F`, `FALSE`, `false`, `False` — and nothing
+else. `yes`, `on`, and `off` are rejected rather than quietly treated
+as false.
 
 On first startup, webhooker automatically generates a cryptographically
 secure session encryption key and stores it in the database. This key

TODO.md

@@ -10,28 +10,28 @@
 
 # Status
 
-pre-1.0. No git tags exist. main (afe88c6) is a working webhook proxy
+pre-1.0. No git tags exist. main (4f5ecb1) is a working webhook proxy
 with auth, CSRF/SSRF protections, login rate limiting, Slack target,
-policy compliance (#6), and pinned lint tooling (#55). Note: TODO.md was
-deliberately deleted from this repo in f9a9569 (2026-03-01, #6); its
-content was folded into the README TODO section, which this draft
-reconstructs as of 2026-07-06.
+policy compliance (#6), pinned lint tooling (#55), a per-webhook event
+retention reaper (#63), and fail-loud configuration parsing (#80). Note:
+TODO.md was deliberately deleted from this repo in f9a9569 (2026-03-01,
+#6); its content was folded into the README TODO section, which this
+draft reconstructs as of 2026-07-06.
 
 # Next Step
 
-Implement automatic event retention cleanup based on retention_days: a
-periodic maintenance job that deletes Events, Deliveries, and
-DeliveryResults older than the parent webhook's retention_days from each
-per-webhook event database. The field exists on the Webhook model and
-the README promises the behavior, but nothing enforces it, so event
-databases currently grow without bound.
+Manual event redelivery from the web UI (replay is a core promised
+capability in the README rationale).
 
 # Completed Steps
 
-- 2026-08-09 Inactivity-based session timeout: sliding idle expiry
-  (`SESSION_IDLE_TIMEOUT`, default `24h`) refreshed on authenticated
-  requests, with the 7-day absolute cap kept as an independent
-  backstop that activity never extends (#66)
+- 2026-08-09 Configuration parsing fails loudly on set-but-unparseable
+  environment values: `envInt` removed in favour of `envPositiveInt`
+  plus a `PORT` range check, `envBool` now parses with
+  `strconv.ParseBool`, and defaults apply only to unset variables (#80)
+- 2026-08-07 Automatic event retention cleanup based on
+  `retention_days`, deleting expired events, deliveries, and delivery
+  results from each per-webhook event database (#63)
 - 2026-08-07 Update golangci-lint to v2.12.2 (Docker image digest in
   `Dockerfile`, release-archive sha256 pins in `script/bootstrap`),
   adopt the canonical `.golangci.yml` (v2 `linters.settings` layout so
@@ -60,8 +60,6 @@ databases currently grow without bound.
 
 # Future Steps
 
-- Manual event redelivery from the web UI (replay is a core promised
-  capability in the README rationale)
 - Delivery status and retry management UI
 - Per-webhook rate limiting in the receiver handler (per-webhook config
   plus handler enforcement; global limits must not apply to receiver
@@ -75,7 +73,7 @@ databases currently grow without bound.
     - event redelivery endpoint
     - OpenAPI specification
 - Analytics dashboard: success rates, response times, volume
-- A remember-me option at login
+- Session expiration tuning and a remember-me option
 - Password change and reset flow
 - Later, nice to have
     - email delivery target type

internal/config/config.go

@@ -7,7 +7,6 @@ import (
 	"log/slog"
 	"os"
 	"strconv"
-	"strings"
 	"time"
 
 	"go.uber.org/fx"
@@ -32,15 +31,23 @@ const (
 	// reaper deletes events older than each webhook's RetentionDays.
 	defaultRetentionSweepInterval = time.Hour
 
-	// defaultSessionIdleTimeout is how long a session may go without
-	// authenticated activity before it expires.
-	defaultSessionIdleTimeout = 24 * time.Hour
+	// maxPort is the highest valid TCP port number. The lower
+	// bound (at least 1) is enforced by envPositiveInt.
+	maxPort = 65535
 )
 
 // ErrInvalidEnvironment is returned when WEBHOOKER_ENVIRONMENT
 // contains an unrecognised value.
 var ErrInvalidEnvironment = errors.New("invalid environment")
 
+// ErrNonPositiveValue is returned when an environment variable that
+// requires a positive integer is set to zero or a negative number.
+var ErrNonPositiveValue = errors.New("value must be positive")
+
+// ErrInvalidPort is returned when an environment variable holding a
+// TCP port number is set above the valid port range.
+var ErrInvalidPort = errors.New("invalid port")
+
 //nolint:revive // ConfigParams is a standard fx naming convention.
 type ConfigParams struct {
 	fx.In
@@ -64,10 +71,6 @@ type Config struct {
 	// RetentionSweepInterval is how often the retention reaper runs.
 	RetentionSweepInterval time.Duration
 
-	// SessionIdleTimeout is the sliding inactivity window after
-	// which a session expires. Non-positive disables idle expiry.
-	SessionIdleTimeout time.Duration
-
 	params *ConfigParams
 	log    *slog.Logger
 }
@@ -89,27 +92,81 @@ func envString(key string) string {
 }
 
 // envBool returns the value of the named environment variable
-// parsed as a boolean. Returns defaultValue if not set.
-func envBool(key string, defaultValue bool) bool {
-	if v := os.Getenv(key); v != "" {
-		return strings.EqualFold(v, "true") || v == "1"
+// parsed as a boolean. Returns defaultValue if not set. If the
+// variable is set but cannot be parsed, it returns a wrapped error
+// naming the key and the bad value, so startup fails loudly rather
+// than silently falling back to the default.
+//
+// Parsing is strconv.ParseBool, which accepts 1, t, T, TRUE, true,
+// True, 0, f, F, FALSE, false and False. Anything else — "yes",
+// "on", or a typo like "ture" — is an error rather than a silent
+// false.
+func envBool(key string, defaultValue bool) (bool, error) {
+	v := os.Getenv(key)
+	if v == "" {
+		return defaultValue, nil
 	}
 
-	return defaultValue
+	b, err := strconv.ParseBool(v)
+	if err != nil {
+		return false, fmt.Errorf(
+			"invalid boolean for %s: %q: %w", key, v, err,
+		)
+	}
+
+	return b, nil
 }
 
-// envInt returns the value of the named environment variable
-// parsed as an integer. Returns defaultValue if not set or
-// unparseable.
-func envInt(key string, defaultValue int) int {
-	if v := os.Getenv(key); v != "" {
-		i, err := strconv.Atoi(v)
-		if err == nil {
-			return i
-		}
+// envPositiveInt returns the value of the named environment variable
+// parsed as a positive integer. Returns defaultValue if not set. If
+// the variable is set but cannot be parsed, or parses to less than
+// one, it returns a wrapped error naming the key and the bad value,
+// so startup fails loudly rather than silently falling back to the
+// default.
+func envPositiveInt(
+	key string,
+	defaultValue int,
+) (int, error) {
+	v := os.Getenv(key)
+	if v == "" {
+		return defaultValue, nil
 	}
 
-	return defaultValue
+	i, err := strconv.Atoi(v)
+	if err != nil {
+		return 0, fmt.Errorf(
+			"invalid integer for %s: %q: %w", key, v, err,
+		)
+	}
+
+	if i < 1 {
+		return 0, fmt.Errorf(
+			"%w: %s must be at least 1, got %q",
+			ErrNonPositiveValue, key, v,
+		)
+	}
+
+	return i, nil
+}
+
+// envPort returns the value of the named environment variable parsed
+// as a TCP port number. Returns defaultValue if not set. A set value
+// that is unparseable, below 1, or above maxPort is a hard error
+// naming the key and the bad value.
+func envPort(key string, defaultValue int) (int, error) {
+	port, err := envPositiveInt(key, defaultValue)
+	if err != nil {
+		return 0, err
+	}
+
+	if port > maxPort {
+		return 0, fmt.Errorf(
+			"%w: %s must be at most %d, got %d",
+			ErrInvalidPort, key, maxPort, port,
+		)
+	}
+
+	return port, nil
 }
 
 // envDuration returns the value of the named environment variable
@@ -136,32 +193,52 @@ func envDuration(
 	return d, nil
 }
 
-// New creates a Config by reading environment variables.
-//
-//nolint:revive // lc parameter is required by fx even if unused.
-func New(lc fx.Lifecycle, params ConfigParams) (*Config, error) {
-	log := params.Logger.Get()
-
-	// Determine environment from WEBHOOKER_ENVIRONMENT env var,
-	// default to dev
+// resolveEnvironment reads WEBHOOKER_ENVIRONMENT, defaulting to
+// dev, and rejects unrecognised values.
+func resolveEnvironment() (string, error) {
 	environment := os.Getenv("WEBHOOKER_ENVIRONMENT")
 	if environment == "" {
 		environment = EnvironmentDev
 	}
 
-	// Validate environment
 	if environment != EnvironmentDev &&
 		environment != EnvironmentProd {
-		return nil, fmt.Errorf(
+		return "", fmt.Errorf(
 			"%w: WEBHOOKER_ENVIRONMENT must be '%s' or '%s', got '%s'",
 			ErrInvalidEnvironment,
 			EnvironmentDev, EnvironmentProd, environment,
 		)
 	}
 
-	// Parse the retention sweep interval; a set-but-unparseable value
-	// is a hard error so fx aborts startup rather than silently using
-	// the default.
+	return environment, nil
+}
+
+// loadFromEnv builds a Config from the environment. Every value that
+// needs parsing fails loudly when it is set but unparseable: the
+// documented defaults apply only to variables that are unset (or
+// empty), never as a substitute for a value the operator actually
+// provided.
+func loadFromEnv() (*Config, error) {
+	environment, err := resolveEnvironment()
+	if err != nil {
+		return nil, err
+	}
+
+	port, err := envPort("PORT", defaultPort)
+	if err != nil {
+		return nil, err
+	}
+
+	debug, err := envBool("DEBUG", false)
+	if err != nil {
+		return nil, err
+	}
+
+	maintenanceMode, err := envBool("MAINTENANCE_MODE", false)
+	if err != nil {
+		return nil, err
+	}
+
 	retentionSweepInterval, err := envDuration(
 		"RETENTION_SWEEP_INTERVAL",
 		defaultRetentionSweepInterval,
@@ -170,30 +247,35 @@ func New(lc fx.Lifecycle, params ConfigParams) (*Config, error) {
 		return nil, err
 	}
 
-	// Same fail-loud treatment for the session idle timeout.
-	sessionIdleTimeout, err := envDuration(
-		"SESSION_IDLE_TIMEOUT",
-		defaultSessionIdleTimeout,
-	)
+	return &Config{
+		DataDir:                envString("DATA_DIR"),
+		Debug:                  debug,
+		MaintenanceMode:        maintenanceMode,
+		Environment:            environment,
+		MetricsUsername:        envString("METRICS_USERNAME"),
+		MetricsPassword:        envString("METRICS_PASSWORD"),
+		Port:                   port,
+		SentryDSN:              envString("SENTRY_DSN"),
+		RetentionSweepInterval: retentionSweepInterval,
+	}, nil
+}
+
+// New creates a Config by reading environment variables.
+//
+//nolint:revive // lc parameter is required by fx even if unused.
+func New(lc fx.Lifecycle, params ConfigParams) (*Config, error) {
+	log := params.Logger.Get()
+
+	// A set-but-unparseable value anywhere in the environment is a
+	// hard error, so fx aborts startup rather than running with a
+	// silently substituted default.
+	s, err := loadFromEnv()
 	if err != nil {
 		return nil, err
 	}
 
-	// Load configuration values from environment variables
-	s := &Config{
-		DataDir:                envString("DATA_DIR"),
-		Debug:                  envBool("DEBUG", false),
-		MaintenanceMode:        envBool("MAINTENANCE_MODE", false),
-		Environment:            environment,
-		MetricsUsername:        envString("METRICS_USERNAME"),
-		MetricsPassword:        envString("METRICS_PASSWORD"),
-		Port:                   envInt("PORT", defaultPort),
-		SentryDSN:              envString("SENTRY_DSN"),
-		RetentionSweepInterval: retentionSweepInterval,
-		SessionIdleTimeout:     sessionIdleTimeout,
-		log:                    log,
-		params:                 &params,
-	}
+	s.log = log
+	s.params = &params
 
 	// Set default DataDir. All SQLite databases (main application
 	// DB and per-webhook event DBs) live here. The same default is

internal/config/config_test.go

@@ -163,7 +163,7 @@ func TestRetentionSweepInterval(t *testing.T) {
 			}
 
 			if tt.expectError {
-				expectStartupError(t)
+				testRetentionSweepIntervalError(t)
 			} else {
 				testRetentionSweepIntervalSuccess(t, tt.expected)
 			}
@@ -171,9 +171,7 @@ func TestRetentionSweepInterval(t *testing.T) {
 	}
 }
 
-// expectStartupError asserts that fx refuses to build the app,
-// which is what a set-but-unparseable duration must cause.
-func expectStartupError(t *testing.T) {
+func testRetentionSweepIntervalError(t *testing.T) {
 	t.Helper()
 
 	var cfg *config.Config
@@ -217,82 +215,6 @@ func testRetentionSweepIntervalSuccess(
 	assert.Equal(t, expected, cfg.RetentionSweepInterval)
 }
 
-func TestSessionIdleTimeout(t *testing.T) {
-	tests := []struct {
-		name        string
-		set         bool
-		value       string
-		expectError bool
-		expected    time.Duration
-	}{
-		{
-			name:     "unset uses default",
-			set:      false,
-			expected: 24 * time.Hour,
-		},
-		{
-			name:     "valid value is parsed",
-			set:      true,
-			value:    "30m",
-			expected: 30 * time.Minute,
-		},
-		{
-			name:        "unparseable value fails startup",
-			set:         true,
-			value:       "not-a-duration",
-			expectError: true,
-		},
-	}
-
-	for _, tt := range tests {
-		t.Run(tt.name, func(t *testing.T) {
-			// Cannot use t.Parallel() here because t.Setenv
-			// is incompatible with parallel subtests.
-			t.Setenv("WEBHOOKER_ENVIRONMENT", "dev")
-
-			if tt.set {
-				t.Setenv("SESSION_IDLE_TIMEOUT", tt.value)
-			} else {
-				require.NoError(t, os.Unsetenv(
-					"SESSION_IDLE_TIMEOUT",
-				))
-			}
-
-			if tt.expectError {
-				expectStartupError(t)
-			} else {
-				testSessionIdleTimeoutSuccess(t, tt.expected)
-			}
-		})
-	}
-}
-
-func testSessionIdleTimeoutSuccess(
-	t *testing.T,
-	expected time.Duration,
-) {
-	t.Helper()
-
-	var cfg *config.Config
-
-	app := fxtest.New(
-		t,
-		fx.Provide(
-			globals.New,
-			logger.New,
-			config.New,
-		),
-		fx.Populate(&cfg),
-	)
-	require.NoError(t, app.Err())
-
-	app.RequireStart()
-
-	defer app.RequireStop()
-
-	assert.Equal(t, expected, cfg.SessionIdleTimeout)
-}
-
 func TestDefaultDataDir(t *testing.T) {
 	for _, env := range []string{"", "dev", "prod"} {
 		name := env

internal/config/env_test.go

@@ -0,0 +1,409 @@
+package config_test
+
+import (
+	"os"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+	"go.uber.org/fx"
+	"sneak.berlin/go/webhooker/internal/config"
+	"sneak.berlin/go/webhooker/internal/globals"
+	"sneak.berlin/go/webhooker/internal/logger"
+)
+
+// testEnvKey is a throwaway variable name used only by the helper
+// tables below, so they cannot disturb real configuration.
+const testEnvKey = "WEBHOOKER_TEST_VALUE"
+
+// Real configuration variables exercised by the config.New tests.
+const (
+	envKeyPort            = "PORT"
+	envKeyDebug           = "DEBUG"
+	envKeyMaintenanceMode = "MAINTENANCE_MODE"
+)
+
+// envBoolCase is one row of the envBool table.
+type envBoolCase struct {
+	name         string
+	set          bool
+	value        string
+	defaultValue bool
+	expectError  bool
+	expected     bool
+}
+
+// envBoolCases is the envBool table, kept out of the test body so
+// the test itself stays readable.
+func envBoolCases() []envBoolCase {
+	return []envBoolCase{
+		{
+			name:         "unset uses default false",
+			defaultValue: false,
+			expected:     false,
+		},
+		{
+			name:         "unset uses default true",
+			defaultValue: true,
+			expected:     true,
+		},
+		{
+			name:         "empty uses default true",
+			set:          true,
+			value:        "",
+			defaultValue: true,
+			expected:     true,
+		},
+		{
+			name:     "true is parsed",
+			set:      true,
+			value:    "true",
+			expected: true,
+		},
+		{
+			name:     "one is parsed",
+			set:      true,
+			value:    "1",
+			expected: true,
+		},
+		{
+			name:         "False is parsed",
+			set:          true,
+			value:        "False",
+			defaultValue: true,
+			expected:     false,
+		},
+		{
+			name:         "zero is parsed",
+			set:          true,
+			value:        "0",
+			defaultValue: true,
+			expected:     false,
+		},
+		{
+			name:        "yes is rejected",
+			set:         true,
+			value:       "yes",
+			expectError: true,
+		},
+		{
+			name:        "on is rejected",
+			set:         true,
+			value:       "on",
+			expectError: true,
+		},
+		{
+			name:        "typo is rejected",
+			set:         true,
+			value:       "ture",
+			expectError: true,
+		},
+	}
+}
+
+func TestEnvBool(t *testing.T) {
+	for _, tt := range envBoolCases() {
+		t.Run(tt.name, func(t *testing.T) {
+			// Cannot use t.Parallel() here because t.Setenv
+			// is incompatible with parallel subtests.
+			if tt.set {
+				t.Setenv(testEnvKey, tt.value)
+			} else {
+				require.NoError(t, os.Unsetenv(testEnvKey))
+			}
+
+			got, err := config.EnvBoolForTest(
+				testEnvKey, tt.defaultValue,
+			)
+
+			if tt.expectError {
+				require.Error(t, err)
+				assert.Contains(t, err.Error(), testEnvKey)
+				assert.Contains(t, err.Error(), tt.value)
+
+				return
+			}
+
+			require.NoError(t, err)
+			assert.Equal(t, tt.expected, got)
+		})
+	}
+}
+
+func TestEnvPositiveInt(t *testing.T) {
+	const defaultValue = 7
+
+	tests := []struct {
+		name        string
+		set         bool
+		value       string
+		expectError bool
+		errIs       error
+		expected    int
+	}{
+		{
+			name:     "unset returns the default integer",
+			expected: defaultValue,
+		},
+		{
+			name:     "empty returns the default integer",
+			set:      true,
+			value:    "",
+			expected: defaultValue,
+		},
+		{
+			name:     "positive value is parsed",
+			set:      true,
+			value:    "42",
+			expected: 42,
+		},
+		{
+			name:        "unparseable value is rejected",
+			set:         true,
+			value:       "not-a-number",
+			expectError: true,
+		},
+		{
+			name:        "zero is rejected",
+			set:         true,
+			value:       "0",
+			expectError: true,
+			errIs:       config.ErrNonPositiveValue,
+		},
+		{
+			name:        "negative is rejected",
+			set:         true,
+			value:       "-5",
+			expectError: true,
+			errIs:       config.ErrNonPositiveValue,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			// Cannot use t.Parallel() here because t.Setenv
+			// is incompatible with parallel subtests.
+			if tt.set {
+				t.Setenv(testEnvKey, tt.value)
+			} else {
+				require.NoError(t, os.Unsetenv(testEnvKey))
+			}
+
+			got, err := config.EnvPositiveIntForTest(
+				testEnvKey, defaultValue,
+			)
+
+			if tt.expectError {
+				require.Error(t, err)
+				assert.Contains(t, err.Error(), testEnvKey)
+				assert.Contains(t, err.Error(), tt.value)
+
+				if tt.errIs != nil {
+					require.ErrorIs(t, err, tt.errIs)
+				}
+
+				return
+			}
+
+			require.NoError(t, err)
+			assert.Equal(t, tt.expected, got)
+		})
+	}
+}
+
+func TestEnvPort(t *testing.T) {
+	const defaultValue = 8080
+
+	tests := []struct {
+		name        string
+		set         bool
+		value       string
+		expectError bool
+		errIs       error
+		expected    int
+	}{
+		{
+			name:     "unset returns the default port",
+			expected: defaultValue,
+		},
+		{
+			name:     "valid port is parsed",
+			set:      true,
+			value:    "9000",
+			expected: 9000,
+		},
+		{
+			name:     "highest port is accepted",
+			set:      true,
+			value:    "65535",
+			expected: 65535,
+		},
+		{
+			name:        "unparseable value is rejected",
+			set:         true,
+			value:       "not-a-port",
+			expectError: true,
+		},
+		{
+			name:        "zero is rejected",
+			set:         true,
+			value:       "0",
+			expectError: true,
+			errIs:       config.ErrNonPositiveValue,
+		},
+		{
+			name:        "above the port range is rejected",
+			set:         true,
+			value:       "65536",
+			expectError: true,
+			errIs:       config.ErrInvalidPort,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			// Cannot use t.Parallel() here because t.Setenv
+			// is incompatible with parallel subtests.
+			if tt.set {
+				t.Setenv(testEnvKey, tt.value)
+			} else {
+				require.NoError(t, os.Unsetenv(testEnvKey))
+			}
+
+			got, err := config.EnvPortForTest(
+				testEnvKey, defaultValue,
+			)
+
+			if tt.expectError {
+				require.Error(t, err)
+				assert.Contains(t, err.Error(), testEnvKey)
+
+				if tt.errIs != nil {
+					require.ErrorIs(t, err, tt.errIs)
+				}
+
+				return
+			}
+
+			require.NoError(t, err)
+			assert.Equal(t, tt.expected, got)
+		})
+	}
+}
+
+// buildConfig constructs a Config through fx exactly as the
+// application does, returning the config and any construction error.
+func buildConfig(t *testing.T) (*config.Config, error) {
+	t.Helper()
+
+	var cfg *config.Config
+
+	app := fx.New(
+		fx.NopLogger,
+		fx.Provide(
+			globals.New,
+			logger.New,
+			config.New,
+		),
+		fx.Populate(&cfg),
+	)
+
+	return cfg, app.Err()
+}
+
+func TestNewRejectsBadEnvValues(t *testing.T) {
+	tests := []struct {
+		name        string
+		key         string
+		value       string
+		expectError bool
+		check       func(t *testing.T, cfg *config.Config)
+	}{
+		{
+			name:  "valid PORT is used",
+			key:   envKeyPort,
+			value: "9001",
+			check: func(t *testing.T, cfg *config.Config) {
+				t.Helper()
+				assert.Equal(t, 9001, cfg.Port)
+			},
+		},
+		{
+			name:        "unparseable PORT aborts startup",
+			key:         envKeyPort,
+			value:       "eighty-eighty",
+			expectError: true,
+		},
+		{
+			name:        "out-of-range PORT aborts startup",
+			key:         envKeyPort,
+			value:       "70000",
+			expectError: true,
+		},
+		{
+			name:  "valid DEBUG is used",
+			key:   envKeyDebug,
+			value: "true",
+			check: func(t *testing.T, cfg *config.Config) {
+				t.Helper()
+				assert.True(t, cfg.Debug)
+			},
+		},
+		{
+			name:        "unparseable DEBUG aborts startup",
+			key:         envKeyDebug,
+			value:       "ture",
+			expectError: true,
+		},
+		{
+			name:        "unparseable MAINTENANCE_MODE aborts startup",
+			key:         envKeyMaintenanceMode,
+			value:       "sometimes",
+			expectError: true,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			// Cannot use t.Parallel() here because t.Setenv
+			// is incompatible with parallel subtests.
+			t.Setenv("WEBHOOKER_ENVIRONMENT", "dev")
+			t.Setenv(tt.key, tt.value)
+
+			cfg, err := buildConfig(t)
+
+			if tt.expectError {
+				require.Error(t, err)
+				assert.Contains(t, err.Error(), tt.key)
+				assert.Contains(t, err.Error(), tt.value)
+
+				return
+			}
+
+			require.NoError(t, err)
+			require.NotNil(t, cfg)
+			tt.check(t, cfg)
+		})
+	}
+}
+
+// TestNewUsesDefaultsWhenUnset proves the fail-loud behaviour did not
+// break the legitimate unset case: absent variables still get their
+// documented defaults.
+func TestNewUsesDefaultsWhenUnset(t *testing.T) {
+	t.Setenv("WEBHOOKER_ENVIRONMENT", "dev")
+
+	for _, key := range []string{
+		envKeyPort, envKeyDebug, envKeyMaintenanceMode,
+	} {
+		require.NoError(t, os.Unsetenv(key))
+	}
+
+	cfg, err := buildConfig(t)
+	require.NoError(t, err)
+	require.NotNil(t, cfg)
+
+	assert.Equal(t, 8080, cfg.Port)
+	assert.False(t, cfg.Debug)
+	assert.False(t, cfg.MaintenanceMode)
+}

internal/config/export_test.go

@@ -0,0 +1,20 @@
+package config
+
+// This file exposes the unexported environment parsing helpers to
+// the external config_test package so each helper can be covered by
+// its own table-driven test without weakening the package API.
+
+// EnvBoolForTest exposes envBool.
+func EnvBoolForTest(key string, defaultValue bool) (bool, error) {
+	return envBool(key, defaultValue)
+}
+
+// EnvPositiveIntForTest exposes envPositiveInt.
+func EnvPositiveIntForTest(key string, defaultValue int) (int, error) {
+	return envPositiveInt(key, defaultValue)
+}
+
+// EnvPortForTest exposes envPort.
+func EnvPortForTest(key string, defaultValue int) (int, error) {
+	return envPort(key, defaultValue)
+}

internal/middleware/middleware.go

@@ -186,10 +186,6 @@ func (s *Middleware) RequireAuth() func(http.Handler) http.Handler {
 				return
 			}
 
-			// IsAuthenticated also enforces both session expiry
-			// deadlines, so an idle-expired or absolutely-expired
-			// session lands here and is sent back to the login
-			// page.
 			if !s.session.IsAuthenticated(sess) {
 				s.log.Debug(
 					"auth middleware: unauthenticated request",
@@ -203,26 +199,6 @@ func (s *Middleware) RequireAuth() func(http.Handler) http.Handler {
 				return
 			}
 
-			// This request authenticated with the session, so it
-			// counts as activity: push the idle deadline forward.
-			// This is the only place sessions are refreshed, which
-			// is what keeps an unauthenticated request from
-			// extending someone else's session. Touch advances the
-			// idle clock only -- the absolute cap is untouched --
-			// and reports false when nothing changed, so most
-			// requests do not re-issue the cookie. Save before the
-			// handler runs, while the headers are still ours to
-			// write.
-			if s.session.Touch(sess) {
-				err = s.session.Save(r, w, sess)
-				if err != nil {
-					s.log.Error(
-						"auth middleware: failed to refresh session",
-						"error", err,
-					)
-				}
-			}
-
 			next.ServeHTTP(w, r)
 		})
 	}

internal/middleware/middleware_test.go

@@ -8,7 +8,6 @@ import (
 	"net/http/httptest"
 	"os"
 	"testing"
-	"time"
 
 	"github.com/gorilla/sessions"
 	"github.com/stretchr/testify/assert"
@@ -29,30 +28,13 @@ func testMiddleware(
 ) (*middleware.Middleware, *session.Session) {
 	t.Helper()
 
-	m, s, _ := testMiddlewareWithSessionClock(t, env, 0, nil)
-
-	return m, s
-}
-
-// testMiddlewareWithSessionClock is testMiddleware with a
-// configurable session idle timeout and a manually advanced clock,
-// for the session-expiry tests. A nil clock uses the real one.
-func testMiddlewareWithSessionClock(
-	t *testing.T,
-	env string,
-	idleTimeout time.Duration,
-	clock *fakeClock,
-) (*middleware.Middleware, *session.Session, *fakeClock) {
-	t.Helper()
-
 	log := slog.New(slog.NewTextHandler(
 		os.Stderr,
 		&slog.HandlerOptions{Level: slog.LevelDebug},
 	))
 
 	cfg := &config.Config{
-		Environment:        env,
-		SessionIdleTimeout: idleTimeout,
+		Environment: env,
 	}
 
 	// Create a real session manager with a known key
@@ -71,40 +53,11 @@ func testMiddlewareWithSessionClock(
 		SameSite: http.SameSiteLaxMode,
 	}
 
-	var now func() time.Time
-
-	if clock != nil {
-		now = clock.Now
-	}
-
-	sessManager := session.NewForTest(store, cfg, log, key, now)
+	sessManager := session.NewForTest(store, cfg, log, key)
 
 	m := middleware.NewForTest(log, cfg, sessManager)
 
-	return m, sessManager, clock
-}
-
-// fakeClock is a manually advanced clock, so session expiry can be
-// tested without sleeping.
-type fakeClock struct {
-	t time.Time
-}
-
-func (c *fakeClock) Now() time.Time {
-	return c.t
-}
-
-func (c *fakeClock) Advance(d time.Duration) {
-	c.t = c.t.Add(d)
-}
-
-// newFakeClock returns a clock started at a fixed instant.
-func newFakeClock() *fakeClock {
-	return &fakeClock{
-		t: time.Date(
-			2026, time.January, 2, 3, 4, 5, 0, time.UTC,
-		),
-	}
+	return m, sessManager
 }
 
 // --- Logging Middleware Tests ---
@@ -434,181 +387,6 @@ func TestRequireAuth_UnauthenticatedSession_RedirectsToLogin(
 	assert.Equal(t, "/pages/login", w.Header().Get("Location"))
 }
 
-// --- RequireAuth Session Expiry Tests ---
-
-// loginCookies authenticates a new session and returns the cookies
-// a browser would then send back.
-func loginCookies(
-	t *testing.T,
-	sessManager *session.Session,
-) []*http.Cookie {
-	t.Helper()
-
-	req := httptest.NewRequestWithContext(
-		context.Background(), http.MethodGet, "/login", nil)
-	w := httptest.NewRecorder()
-
-	sess, err := sessManager.Get(req)
-	require.NoError(t, err)
-	sessManager.SetUser(sess, "user-123", "testuser")
-	require.NoError(t, sessManager.Save(req, w, sess))
-
-	cookies := w.Result().Cookies()
-	require.NotEmpty(t, cookies, "session cookie should be set")
-
-	return cookies
-}
-
-// runAuthed sends a request carrying cookies through RequireAuth
-// and reports whether the protected handler ran, plus the response.
-func runAuthed(
-	t *testing.T,
-	m *middleware.Middleware,
-	cookies []*http.Cookie,
-) (bool, *httptest.ResponseRecorder) {
-	t.Helper()
-
-	var called bool
-
-	handler := m.RequireAuth()(http.HandlerFunc(
-		func(_ http.ResponseWriter, _ *http.Request) {
-			called = true
-		},
-	))
-
-	req := httptest.NewRequestWithContext(
-		context.Background(),
-		http.MethodGet, "/dashboard", nil,
-	)
-
-	for _, c := range cookies {
-		req.AddCookie(c)
-	}
-
-	w := httptest.NewRecorder()
-	handler.ServeHTTP(w, req)
-
-	return called, w
-}
-
-// sessionCookies filters a response's cookies down to the session
-// cookie, so tests can tell whether the session was re-issued.
-func sessionCookies(
-	w *httptest.ResponseRecorder,
-) []*http.Cookie {
-	var out []*http.Cookie
-
-	for _, c := range w.Result().Cookies() {
-		if c.Name == session.SessionName {
-			out = append(out, c)
-		}
-	}
-
-	return out
-}
-
-func TestRequireAuth_IdleExpiredSession_RedirectsToLogin(
-	t *testing.T,
-) {
-	t.Parallel()
-
-	idle := time.Hour
-
-	m, sessManager, clock := testMiddlewareWithSessionClock(
-		t, config.EnvironmentDev, idle, newFakeClock(),
-	)
-
-	cookies := loginCookies(t, sessManager)
-
-	clock.Advance(idle)
-
-	called, w := runAuthed(t, m, cookies)
-
-	assert.False(
-		t, called,
-		"handler should not run for an idle-expired session",
-	)
-	assert.Equal(t, http.StatusSeeOther, w.Code)
-	assert.Equal(t, "/pages/login", w.Header().Get("Location"))
-	assert.Empty(
-		t, sessionCookies(w),
-		"an expired session must not be refreshed",
-	)
-}
-
-func TestRequireAuth_RefreshesIdleDeadlineOnActivity(
-	t *testing.T,
-) {
-	t.Parallel()
-
-	idle := time.Hour
-
-	m, sessManager, clock := testMiddlewareWithSessionClock(
-		t, config.EnvironmentDev, idle, newFakeClock(),
-	)
-
-	cookies := loginCookies(t, sessManager)
-
-	// Activity halfway through the idle window.
-	clock.Advance(idle / 2)
-
-	called, w := runAuthed(t, m, cookies)
-	require.True(t, called, "handler should run while valid")
-
-	refreshed := sessionCookies(w)
-	require.NotEmpty(
-		t, refreshed,
-		"activity should re-issue the session cookie",
-	)
-
-	// Past the original deadline. The refreshed cookie is still
-	// good; the original one is not.
-	clock.Advance(idle - time.Second)
-
-	calledRefreshed, _ := runAuthed(t, m, refreshed)
-	assert.True(
-		t, calledRefreshed,
-		"refreshed session should outlive the original deadline",
-	)
-
-	calledStale, staleW := runAuthed(t, m, cookies)
-	assert.False(
-		t, calledStale,
-		"the pre-refresh cookie carries the old idle deadline",
-	)
-	assert.Equal(t, http.StatusSeeOther, staleW.Code)
-}
-
-func TestRequireAuth_UnauthenticatedRequestDoesNotRefresh(
-	t *testing.T,
-) {
-	t.Parallel()
-
-	m, sessManager, _ := testMiddlewareWithSessionClock(
-		t, config.EnvironmentDev, time.Hour, newFakeClock(),
-	)
-
-	// A session cookie that exists but was never authenticated.
-	req := httptest.NewRequestWithContext(
-		context.Background(), http.MethodGet, "/setup", nil)
-	setupW := httptest.NewRecorder()
-
-	sess, err := sessManager.Get(req)
-	require.NoError(t, err)
-	require.NoError(t, sessManager.Save(req, setupW, sess))
-
-	cookies := setupW.Result().Cookies()
-	require.NotEmpty(t, cookies)
-
-	called, w := runAuthed(t, m, cookies)
-
-	assert.False(t, called)
-	assert.Empty(
-		t, sessionCookies(w),
-		"an unauthenticated request must not stamp the session",
-	)
-}
-
 // --- NoCache Middleware Tests ---
 
 func TestNoCache_SetsHeaders(t *testing.T) {
@@ -701,7 +479,7 @@ func metricsAuthMiddleware(
 	store := sessions.NewCookieStore(key)
 	store.Options = &sessions.Options{Path: "/", MaxAge: 86400}
 
-	sessManager := session.NewForTest(store, cfg, log, key, nil)
+	sessManager := session.NewForTest(store, cfg, log, key)
 
 	return middleware.NewForTest(log, cfg, sessManager)
 }

internal/session/session.go

@@ -10,7 +10,6 @@ import (
 	"log/slog"
 	"maps"
 	"net/http"
-	"time"
 
 	"github.com/gorilla/sessions"
 	"go.uber.org/fx"
@@ -33,18 +32,6 @@ const (
 	// status.
 	AuthenticatedKey = "authenticated"
 
-	// CreatedAtKey is the session key holding the Unix timestamp at
-	// which the session was authenticated. It anchors the ABSOLUTE
-	// expiry clock and is written exactly once, by SetUser. Nothing
-	// refreshes it: an absolute deadline that moved with activity
-	// would not be a cap at all.
-	CreatedAtKey = "created_at"
-
-	// LastSeenKey is the session key holding the Unix timestamp of
-	// the most recent authenticated request. It anchors the IDLE
-	// expiry clock and is pushed forward by Touch.
-	LastSeenKey = "last_seen"
-
 	// sessionKeyLength is the required length in bytes for the
 	// session authentication key.
 	sessionKeyLength = 32
@@ -54,19 +41,6 @@ const (
 
 	// secondsPerDay is the number of seconds in a day.
 	secondsPerDay = 86400
-
-	// sessionAbsoluteMaxAge is the hard upper bound on how long a
-	// session may live, measured from CreatedAtKey. Activity never
-	// extends it, so even a continuously used session ends here and
-	// the user has to authenticate again.
-	sessionAbsoluteMaxAge = sessionMaxAgeDays * secondsPerDay * time.Second
-
-	// idleRefreshDivisor rate-limits idle-deadline refreshes. Touch
-	// only rewrites LastSeenKey once the stored value is older than
-	// idleTimeout/idleRefreshDivisor, so an active session is
-	// re-saved at most this many times per idle window instead of
-	// once per request. See Touch for the tradeoff this buys.
-	idleRefreshDivisor = 10
 )
 
 // ErrSessionKeyLength is returned when the decoded session key
@@ -88,16 +62,6 @@ type Session struct {
 	key    []byte // raw 32-byte auth key, also used for CSRF cookie signing
 	log    *slog.Logger
 	config *config.Config
-
-	// idleTimeout is the sliding inactivity window. A session that
-	// sees no authenticated request within this window expires,
-	// independently of the absolute cap. Non-positive disables idle
-	// expiry and leaves sessionAbsoluteMaxAge as the only bound.
-	idleTimeout time.Duration
-
-	// now reads the current time. Injected so expiry can be tested
-	// without sleeping.
-	now func() time.Time
 }
 
 // New creates a new session manager. The cookie store is
@@ -109,10 +73,8 @@ func New(
 	params Params,
 ) (*Session, error) {
 	s := &Session{
-		log:         params.Logger.Get(),
-		config:      params.Config,
-		idleTimeout: params.Config.SessionIdleTimeout,
-		now:         time.Now,
+		log:    params.Logger.Get(),
+		config: params.Config,
 	}
 
 	lc.Append(fx.Hook{
@@ -187,98 +149,29 @@ func (s *Session) Save(
 	return sess.Save(r, w)
 }
 
-// SetUser sets the user information in the session. It starts both
-// expiry clocks: CreatedAtKey (absolute, never refreshed again) and
-// LastSeenKey (idle, refreshed by Touch).
+// SetUser sets the user information in the session.
 func (s *Session) SetUser(
 	sess *sessions.Session,
 	userID, username string,
 ) {
-	now := s.now().Unix()
-
 	sess.Values[UserIDKey] = userID
 	sess.Values[UsernameKey] = username
 	sess.Values[AuthenticatedKey] = true
-	sess.Values[CreatedAtKey] = now
-	sess.Values[LastSeenKey] = now
 }
 
-// ClearUser removes user information from the session, including
-// both expiry timestamps.
+// ClearUser removes user information from the session.
 func (s *Session) ClearUser(sess *sessions.Session) {
 	delete(sess.Values, UserIDKey)
 	delete(sess.Values, UsernameKey)
 	delete(sess.Values, AuthenticatedKey)
-	delete(sess.Values, CreatedAtKey)
-	delete(sess.Values, LastSeenKey)
 }
 
-// sessionTime reads a Unix-second timestamp stored under key.
-func sessionTime(
-	sess *sessions.Session,
-	key string,
-) (time.Time, bool) {
-	secs, ok := sess.Values[key].(int64)
-	if !ok {
-		return time.Time{}, false
-	}
-
-	return time.Unix(secs, 0), true
-}
-
-// IsAuthenticated checks if the session has an authenticated user
-// whose session has not passed either expiry deadline. Every
-// authentication decision goes through here, so neither clock can
-// be bypassed by a caller that forgets to check it.
+// IsAuthenticated checks if the session has an authenticated
+// user.
 func (s *Session) IsAuthenticated(sess *sessions.Session) bool {
 	auth, ok := sess.Values[AuthenticatedKey].(bool)
-	if !ok || !auth {
-		return false
-	}
 
-	return !s.expired(sess)
-}
-
-// Touch records authenticated activity by pushing the IDLE deadline
-// forward. It writes LastSeenKey only; CreatedAtKey is left alone so
-// the absolute cap keeps counting down even for a user who never
-// stops clicking.
-//
-// Callers must only invoke Touch for a request that authenticated
-// with this session. Refreshing on an unauthenticated request would
-// let anyone holding a stolen or abandoned cookie keep the session
-// alive by polling a public endpoint. Touch enforces that itself by
-// returning false for any session that is not currently
-// authenticated and unexpired.
-//
-// To avoid re-encrypting and re-emitting the session cookie on every
-// single request, the timestamp is advanced only once it is older
-// than idleTimeout/idleRefreshDivisor. The tradeoff is that
-// LastSeenKey lags real activity by up to that much, so a session
-// can expire slightly early relative to the user's true last
-// request -- never late.
-//
-// Touch reports whether it changed the session; only then does the
-// caller need to save it.
-func (s *Session) Touch(sess *sessions.Session) bool {
-	if s.idleTimeout <= 0 {
-		return false
-	}
-
-	if !s.IsAuthenticated(sess) {
-		return false
-	}
-
-	now := s.now()
-
-	lastSeen, ok := sessionTime(sess, LastSeenKey)
-	if ok && now.Sub(lastSeen) < s.idleTimeout/idleRefreshDivisor {
-		return false
-	}
-
-	sess.Values[LastSeenKey] = now.Unix()
-
-	return true
+	return ok && auth
 }
 
 // GetUserID retrieves the user ID from the session.
@@ -360,41 +253,3 @@ func (s *Session) Regenerate(
 
 	return newSess, nil
 }
-
-// expired reports whether the session has passed either of its two
-// independent deadlines. They are deliberately kept apart:
-//
-//   - the ABSOLUTE deadline is CreatedAtKey + sessionAbsoluteMaxAge.
-//     It is fixed at login and no amount of activity moves it.
-//   - the IDLE deadline is LastSeenKey + idleTimeout. Activity moves
-//     it forward via Touch.
-//
-// Whichever comes first ends the session.
-//
-// A session that claims to be authenticated but carries no
-// timestamps predates this check; it is treated as expired so the
-// user re-authenticates rather than being granted an unbounded
-// session.
-func (s *Session) expired(sess *sessions.Session) bool {
-	now := s.now()
-
-	createdAt, ok := sessionTime(sess, CreatedAtKey)
-	if !ok {
-		return true
-	}
-
-	if !now.Before(createdAt.Add(sessionAbsoluteMaxAge)) {
-		return true
-	}
-
-	if s.idleTimeout <= 0 {
-		return false
-	}
-
-	lastSeen, ok := sessionTime(sess, LastSeenKey)
-	if !ok {
-		return true
-	}
-
-	return !now.Before(lastSeen.Add(s.idleTimeout))
-}

internal/session/session_test.go

@@ -7,7 +7,6 @@ import (
 	"net/http/httptest"
 	"os"
 	"testing"
-	"time"
 
 	"github.com/gorilla/sessions"
 	"github.com/stretchr/testify/assert"
@@ -18,47 +17,11 @@ import (
 
 const testKeySize = 32
 
-// testIdleTimeout is the idle window used by the expiry tests.
-const testIdleTimeout = time.Hour
-
-// testAbsoluteMaxAge restates the documented absolute session cap
-// independently of the implementation constant.
-const testAbsoluteMaxAge = 7 * 24 * time.Hour
-
-// fakeClock is a manually advanced clock, so expiry can be tested
-// without sleeping.
-type fakeClock struct {
-	t time.Time
-}
-
-func (c *fakeClock) Now() time.Time {
-	return c.t
-}
-
-func (c *fakeClock) Advance(d time.Duration) {
-	c.t = c.t.Add(d)
-}
-
-// testSession creates a Session with a real cookie store and the
-// real clock.
+// testSession creates a Session with a real cookie store for
+// testing.
 func testSession(t *testing.T) *session.Session {
 	t.Helper()
 
-	s, _ := testSessionWithClock(t, testIdleTimeout, nil)
-
-	return s
-}
-
-// testSessionWithClock creates a Session with a real cookie store,
-// the given idle timeout, and a manually advanced clock. Passing a
-// nil clock uses the real one.
-func testSessionWithClock(
-	t *testing.T,
-	idleTimeout time.Duration,
-	clock *fakeClock,
-) (*session.Session, *fakeClock) {
-	t.Helper()
-
 	key := make([]byte, testKeySize)
 
 	for i := range key {
@@ -75,8 +38,7 @@ func testSessionWithClock(
 	}
 
 	cfg := &config.Config{
-		Environment:        config.EnvironmentDev,
-		SessionIdleTimeout: idleTimeout,
+		Environment: config.EnvironmentDev,
 	}
 
 	log := slog.New(slog.NewTextHandler(
@@ -84,46 +46,7 @@ func testSessionWithClock(
 		&slog.HandlerOptions{Level: slog.LevelDebug},
 	))
 
-	var now func() time.Time
-
-	if clock != nil {
-		now = clock.Now
-	}
-
-	return session.NewForTest(store, cfg, log, key, now), clock
-}
-
-// newFakeClock returns a clock started at a fixed instant.
-func newFakeClock() *fakeClock {
-	return &fakeClock{
-		t: time.Date(
-			2026, time.January, 2, 3, 4, 5, 0, time.UTC,
-		),
-	}
-}
-
-// authenticatedSession returns a fresh session that has just been
-// logged in, along with its manager and clock.
-func authenticatedSession(
-	t *testing.T,
-	idleTimeout time.Duration,
-) (*session.Session, *sessions.Session, *fakeClock) {
-	t.Helper()
-
-	s, clock := testSessionWithClock(
-		t, idleTimeout, newFakeClock(),
-	)
-
-	req := httptest.NewRequestWithContext(
-		context.Background(), http.MethodGet, "/", nil)
-
-	sess, err := s.Get(req)
-	require.NoError(t, err)
-
-	s.SetUser(sess, "user-123", "alice")
-	require.True(t, s.IsAuthenticated(sess))
-
-	return s, sess, clock
+	return session.NewForTest(store, cfg, log, key)
 }
 
 // --- Get and Save Tests ---
@@ -507,263 +430,6 @@ func TestSessionConstants(t *testing.T) {
 	assert.Equal(t, "user_id", session.UserIDKey)
 	assert.Equal(t, "username", session.UsernameKey)
 	assert.Equal(t, "authenticated", session.AuthenticatedKey)
-	assert.Equal(t, "created_at", session.CreatedAtKey)
-	assert.Equal(t, "last_seen", session.LastSeenKey)
-}
-
-// --- Expiry Tests ---
-
-func TestSetUser_StartsBothClocks(t *testing.T) {
-	t.Parallel()
-
-	_, sess, clock := authenticatedSession(t, testIdleTimeout)
-
-	assert.Equal(
-		t, clock.Now().Unix(), sess.Values[session.CreatedAtKey],
-		"SetUser should anchor the absolute clock",
-	)
-	assert.Equal(
-		t, clock.Now().Unix(), sess.Values[session.LastSeenKey],
-		"SetUser should anchor the idle clock",
-	)
-}
-
-func TestIsAuthenticated_WithinIdleWindow(t *testing.T) {
-	t.Parallel()
-
-	s, sess, clock := authenticatedSession(t, testIdleTimeout)
-
-	clock.Advance(testIdleTimeout - time.Second)
-
-	assert.True(
-		t, s.IsAuthenticated(sess),
-		"session should still be valid just inside the idle window",
-	)
-}
-
-func TestIsAuthenticated_IdleExpired(t *testing.T) {
-	t.Parallel()
-
-	s, sess, clock := authenticatedSession(t, testIdleTimeout)
-
-	clock.Advance(testIdleTimeout)
-
-	assert.False(
-		t, s.IsAuthenticated(sess),
-		"session should expire once the idle window lapses",
-	)
-}
-
-// TestTouch_DoesNotExtendAbsoluteCap is the regression test for the
-// refresh-the-wrong-clock bug: a session that is used continuously
-// must survive well past the idle window and still die at the
-// absolute cap.
-func TestTouch_DoesNotExtendAbsoluteCap(t *testing.T) {
-	t.Parallel()
-
-	s, sess, clock := authenticatedSession(t, testIdleTimeout)
-
-	createdAt := sess.Values[session.CreatedAtKey]
-
-	// Stay active: a request every half idle window, right up to
-	// the absolute cap.
-	step := testIdleTimeout / 2
-	steps := int(testAbsoluteMaxAge/step) - 1
-
-	for i := range steps {
-		clock.Advance(step)
-		s.Touch(sess)
-
-		require.True(
-			t, s.IsAuthenticated(sess),
-			"active session should survive the idle window "+
-				"(step %d of %d)", i+1, steps,
-		)
-	}
-
-	// One more step of activity takes the session to exactly the
-	// absolute cap, measured from login. Nothing that happened in
-	// the loop may have moved that deadline.
-	clock.Advance(step)
-	s.Touch(sess)
-
-	assert.False(
-		t, s.IsAuthenticated(sess),
-		"activity must not extend the absolute cap",
-	)
-	assert.Equal(
-		t, createdAt, sess.Values[session.CreatedAtKey],
-		"Touch must never rewrite the absolute-clock anchor",
-	)
-}
-
-func TestTouch_RefreshesIdleDeadline(t *testing.T) {
-	t.Parallel()
-
-	s, sess, clock := authenticatedSession(t, testIdleTimeout)
-
-	// Halfway through the window, activity happens.
-	clock.Advance(testIdleTimeout / 2)
-	assert.True(
-		t, s.Touch(sess),
-		"Touch should refresh once past the lazy-refresh threshold",
-	)
-
-	// Past the original deadline, but inside the refreshed one.
-	clock.Advance(testIdleTimeout - time.Second)
-	assert.True(
-		t, s.IsAuthenticated(sess),
-		"refreshed session should outlive the original deadline",
-	)
-
-	// And it still expires an idle window after that activity.
-	clock.Advance(time.Second)
-	assert.False(
-		t, s.IsAuthenticated(sess),
-		"refreshed session should expire one window after activity",
-	)
-}
-
-func TestTouch_LazyBelowRefreshThreshold(t *testing.T) {
-	t.Parallel()
-
-	s, sess, clock := authenticatedSession(t, testIdleTimeout)
-
-	before := sess.Values[session.LastSeenKey]
-
-	// A request arriving almost immediately is not worth a cookie
-	// rewrite.
-	clock.Advance(time.Second)
-
-	assert.False(
-		t, s.Touch(sess),
-		"Touch should not rewrite the session below the threshold",
-	)
-	assert.Equal(
-		t, before, sess.Values[session.LastSeenKey],
-		"last-seen should be unchanged below the threshold",
-	)
-}
-
-func TestTouch_UnauthenticatedSessionIsNotRefreshed(t *testing.T) {
-	t.Parallel()
-
-	s, clock := testSessionWithClock(
-		t, testIdleTimeout, newFakeClock(),
-	)
-
-	req := httptest.NewRequestWithContext(
-		context.Background(), http.MethodGet, "/", nil)
-
-	sess, err := s.Get(req)
-	require.NoError(t, err)
-
-	clock.Advance(testIdleTimeout / 2)
-
-	assert.False(
-		t, s.Touch(sess),
-		"an unauthenticated session must not be refreshed",
-	)
-
-	_, hasLastSeen := sess.Values[session.LastSeenKey]
-	assert.False(
-		t, hasLastSeen,
-		"Touch must not stamp an unauthenticated session",
-	)
-}
-
-func TestTouch_IdleExpiredSessionIsNotRevived(t *testing.T) {
-	t.Parallel()
-
-	s, sess, clock := authenticatedSession(t, testIdleTimeout)
-
-	clock.Advance(testIdleTimeout)
-	require.False(t, s.IsAuthenticated(sess))
-
-	assert.False(
-		t, s.Touch(sess),
-		"an already expired session must not be refreshed",
-	)
-	assert.False(
-		t, s.IsAuthenticated(sess),
-		"Touch must not revive an expired session",
-	)
-}
-
-func TestIsAuthenticated_MissingTimestamps(t *testing.T) {
-	t.Parallel()
-
-	s, _ := testSessionWithClock(
-		t, testIdleTimeout, newFakeClock(),
-	)
-
-	req := httptest.NewRequestWithContext(
-		context.Background(), http.MethodGet, "/", nil)
-
-	sess, err := s.Get(req)
-	require.NoError(t, err)
-
-	// A session from before idle expiry existed: authenticated,
-	// but with no timestamps. Fail closed.
-	sess.Values[session.AuthenticatedKey] = true
-
-	assert.False(
-		t, s.IsAuthenticated(sess),
-		"a session with no timestamps should be rejected",
-	)
-}
-
-func TestIsAuthenticated_MissingLastSeen(t *testing.T) {
-	t.Parallel()
-
-	s, sess, _ := authenticatedSession(t, testIdleTimeout)
-
-	delete(sess.Values, session.LastSeenKey)
-
-	assert.False(
-		t, s.IsAuthenticated(sess),
-		"a session with no idle anchor should be rejected",
-	)
-}
-
-func TestIdleTimeoutDisabled_AbsoluteCapStillApplies(t *testing.T) {
-	t.Parallel()
-
-	s, sess, clock := authenticatedSession(t, 0)
-
-	// Idle expiry is off, so an untouched session survives an
-	// arbitrary idle stretch.
-	clock.Advance(testAbsoluteMaxAge - time.Second)
-	assert.True(
-		t, s.IsAuthenticated(sess),
-		"idle expiry should be disabled by a non-positive timeout",
-	)
-
-	assert.False(
-		t, s.Touch(sess),
-		"Touch should be a no-op when idle expiry is disabled",
-	)
-
-	// The absolute cap still ends it.
-	clock.Advance(time.Second)
-	assert.False(
-		t, s.IsAuthenticated(sess),
-		"the absolute cap must still apply with idle expiry off",
-	)
-}
-
-func TestClearUser_RemovesTimestamps(t *testing.T) {
-	t.Parallel()
-
-	s, sess, _ := authenticatedSession(t, testIdleTimeout)
-
-	s.ClearUser(sess)
-
-	_, hasCreatedAt := sess.Values[session.CreatedAtKey]
-	assert.False(t, hasCreatedAt, "CreatedAtKey should be removed")
-
-	_, hasLastSeen := sess.Values[session.LastSeenKey]
-	assert.False(t, hasLastSeen, "LastSeenKey should be removed")
 }
 
 // --- Edge Cases ---

internal/session/testing.go

@@ -2,7 +2,6 @@ package session
 
 import (
 	"log/slog"
-	"time"
 
 	"github.com/gorilla/sessions"
 	"sneak.berlin/go/webhooker/internal/config"
@@ -13,28 +12,16 @@ import (
 // middleware and handler tests to use real session functionality. The key
 // parameter is the raw 32-byte authentication key used for session encryption
 // and CSRF cookie signing.
-//
-// The idle timeout is taken from cfg.SessionIdleTimeout, exactly as in
-// production. The now parameter supplies the clock used for expiry
-// checks so tests can advance time without sleeping; pass nil for the
-// real clock.
 func NewForTest(
 	store *sessions.CookieStore,
 	cfg *config.Config,
 	log *slog.Logger,
 	key []byte,
-	now func() time.Time,
 ) *Session {
-	if now == nil {
-		now = time.Now
-	}
-
 	return &Session{
-		store:       store,
-		key:         key,
-		config:      cfg,
-		log:         log,
-		idleTimeout: cfg.SessionIdleTimeout,
-		now:         now,
+		store:  store,
+		key:    key,
+		config: cfg,
+		log:    log,
 	}
 }