Remove the no-op MAINTENANCE_MODE setting (closes #317)

MAINTENANCE_MODE only made the healthcheck report
maintenanceMode: true; no request was ever served differently. It is
removed from the configuration, the healthcheck JSON, the README and
the Settings page, together with the unused Server.MaintenanceMode
method and the healthcheck's Config dependency, which existed only to
read it. A leftover MAINTENANCE_MODE in the environment is not read,
so it is ignored rather than refused.

Model: opus-5-5

internal/config/config.go

@@ -149,7 +149,6 @@ type ConfigParams struct {
 type Config struct {
 	DataDir         string
 	Debug           bool
-	MaintenanceMode bool
 	Environment     string
 	MetricsPassword string
 	MetricsUsername string
@@ -658,11 +657,6 @@ func loadFromEnv() (*Config, error) {
 		return nil, err
 	}
 
-	maintenanceMode, err := envBool("MAINTENANCE_MODE", false)
-	if err != nil {
-		return nil, err
-	}
-
 	retentionSweepInterval, err := envPositiveDuration(
 		"RETENTION_SWEEP_INTERVAL",
 		defaultRetentionSweepInterval,
@@ -712,7 +706,6 @@ func loadFromEnv() (*Config, error) {
 	return &Config{
 		DataDir:                DataDir(),
 		Debug:                  debug,
-		MaintenanceMode:        maintenanceMode,
 		Environment:            environment,
 		MetricsUsername:        metricsUsername,
 		MetricsPassword:        metricsPassword,
@@ -799,7 +792,6 @@ func New(lc fx.Lifecycle, params ConfigParams) (*Config, error) {
 		// host can reach the admin UI.
 		"bindAddress", s.BindAddress,
 		"debug", s.Debug,
-		"maintenanceMode", s.MaintenanceMode,
 		"dataDir", s.DataDir,
 		"retentionSweepInterval", s.RetentionSweepInterval.String(),
 		// Logged because a perfectly valid non-positive value here

internal/config/env_test.go

@@ -18,10 +18,9 @@ const testEnvKey = "WEBHOOKER_TEST_VALUE"
 
 // Real configuration variables exercised by the config.New tests.
 const (
-	envKeyPort            = "PORT"
-	envKeyDebug           = "DEBUG"
-	envKeyMaintenanceMode = "MAINTENANCE_MODE"
-	envKeyBindAddress     = "BIND_ADDRESS"
+	envKeyPort        = "PORT"
+	envKeyDebug       = "DEBUG"
+	envKeyBindAddress = "BIND_ADDRESS"
 )
 
 // Sample BIND_ADDRESS values used by the tables below.
@@ -604,12 +603,6 @@ func flagEnvValueCases() []badEnvValueCase {
 			value:       "ture",
 			expectError: true,
 		},
-		{
-			name:        "unparseable MAINTENANCE_MODE aborts startup",
-			key:         envKeyMaintenanceMode,
-			value:       "sometimes",
-			expectError: true,
-		},
 	}
 }
 
@@ -656,8 +649,7 @@ func TestNewUsesDefaultsWhenUnset(t *testing.T) {
 	t.Setenv("WEBHOOKER_ENVIRONMENT", "dev")
 
 	for _, key := range []string{
-		envKeyPort, envKeyDebug, envKeyMaintenanceMode,
-		envKeyBindAddress, envKeySentryDSN,
+		envKeyPort, envKeyDebug, envKeyBindAddress, envKeySentryDSN,
 	} {
 		require.NoError(t, os.Unsetenv(key))
 	}
@@ -668,7 +660,6 @@ func TestNewUsesDefaultsWhenUnset(t *testing.T) {
 
 	assert.Equal(t, 8080, cfg.Port)
 	assert.False(t, cfg.Debug)
-	assert.False(t, cfg.MaintenanceMode)
 
 	// Loopback, not the wildcard: the default must not publish the
 	// cleartext admin UI and the unauthenticated receiver on every

internal/handlers/settings.go

@@ -53,13 +53,6 @@ func settingRows(cfg *config.Config) []settingRow {
 		},
 		{"DATA_DIR", "Directory for all SQLite databases", cfg.DataDir},
 		{"DEBUG", "Enable debug logging", strconv.FormatBool(cfg.Debug)},
-		{
-			"MAINTENANCE_MODE",
-			"Report maintenanceMode: true in the healthcheck JSON. " +
-				"It does not change how any request is served — no " +
-				"maintenance page exists",
-			strconv.FormatBool(cfg.MaintenanceMode),
-		},
 		{
 			"METRICS_USERNAME",
 			"Basic auth username for /metrics. Must be set together " +

internal/handlers/settings_test.go

@@ -62,14 +62,12 @@ func settingsShown(
 func TestSettingsPageShowsLoadedConfiguration(t *testing.T) {
 	t.Parallel()
 
-	// DEBUG and MAINTENANCE_MODE get opposite values, and each of
-	// METRICS_USERNAME, METRICS_PASSWORD and SENTRY_DSN is the only one
-	// of the three set in one of the content tests, so each row is
-	// checked against its own field.
+	// Each of METRICS_USERNAME, METRICS_PASSWORD and SENTRY_DSN is the
+	// only one of the three set in one of the content tests, so each
+	// row is checked against its own field.
 	cfg := &config.Config{
 		DataDir:                t.TempDir(),
 		Debug:                  true,
-		MaintenanceMode:        false,
 		Environment:            config.EnvironmentDev,
 		MetricsUsername:        "scraper",
 		MetricsPassword:        "",
@@ -96,7 +94,6 @@ func TestSettingsPageShowsLoadedConfiguration(t *testing.T) {
 		"BIND_ADDRESS":             "192.0.2.10",
 		"DATA_DIR":                 cfg.DataDir,
 		"DEBUG":                    "true",
-		"MAINTENANCE_MODE":         "false",
 		"METRICS_USERNAME":         "scraper",
 		"METRICS_PASSWORD":         "not set",
 		"SENTRY_DSN":               "not set",

internal/healthcheck/healthcheck.go

@@ -7,7 +7,6 @@ import (
 	"time"
 
 	"go.uber.org/fx"
-	"sneak.berlin/go/webhooker/internal/config"
 	"sneak.berlin/go/webhooker/internal/database"
 	"sneak.berlin/go/webhooker/internal/globals"
 	"sneak.berlin/go/webhooker/internal/logger"
@@ -18,7 +17,6 @@ type HealthcheckParams struct {
 	fx.In
 
 	Globals  *globals.Globals
-	Config   *config.Config
 	Logger   *logger.Logger
 	Database *database.Database
 }
@@ -64,7 +62,6 @@ func (s *Healthcheck) Healthcheck() *Response {
 		UptimeHuman:   s.uptime().String(),
 		Appname:       s.params.Globals.Appname,
 		Version:       s.params.Globals.Version,
-		Maintenance:   s.params.Config.MaintenanceMode,
 	}
 
 	return resp
@@ -78,7 +75,6 @@ type Response struct {
 	UptimeHuman   string `json:"uptimeHuman"`
 	Version       string `json:"version"`
 	Appname       string `json:"appname"`
-	Maintenance   bool   `json:"maintenanceMode"`
 }
 
 func (s *Healthcheck) uptime() time.Duration {

internal/server/server.go

@@ -159,12 +159,6 @@ func (s *Server) Run() {
 	s.serve()
 }
 
-// MaintenanceMode returns whether the server is in maintenance
-// mode.
-func (s *Server) MaintenanceMode() bool {
-	return s.params.Config.MaintenanceMode
-}
-
 // enableSentry initialises the Sentry SDK when error reporting is
 // configured, and reports the failure when it is configured and cannot
 // be initialised. A DSN that is not set is not a failure: reporting