From 49f55524436ec76bad20544f9b454ca101958f7e Mon Sep 17 00:00:00 2001 From: sneak Date: Thu, 1 Oct 2026 19:07:45 +0000 Subject: [PATCH] config: stop startup on an invalid DNS or TLS interval (closes #177) DNSWATCHER_DNS_INTERVAL and DNSWATCHER_TLS_INTERVAL were parsed with time.ParseDuration and silently replaced by the default when that failed, so a value like 5 or 1d gave hourly checks with no hint why, and zero or negative values were accepted. Both now go through parseInterval, which returns an error naming the variable and the value, and startup stops the same way it does for invalid targets. An unset or empty variable still gets its default from setupViper. The three tests that pinned the old fallback are replaced. The README says what a valid value looks like. Model: opus-5-5 --- README.md | 12 ++++++-- TODO.md | 4 +-- internal/config/config.go | 35 +++++++++++++++++------ internal/config/config_test.go | 52 ++++++++++++++++++++-------------- 4 files changed, 69 insertions(+), 34 deletions(-) diff --git a/README.md b/README.md index ba79f23..9b4ade1 100644 --- a/README.md +++ b/README.md @@ -320,8 +320,8 @@ the following precedence (highest to lowest): | `DNSWATCHER_SLACK_WEBHOOK` | Slack incoming webhook URL | `""` | | `DNSWATCHER_MATTERMOST_WEBHOOK` | Mattermost incoming webhook URL | `""` | | `DNSWATCHER_NTFY_TOPIC` | ntfy topic URL | `""` | -| `DNSWATCHER_DNS_INTERVAL` | DNS check interval | `1h` | -| `DNSWATCHER_TLS_INTERVAL` | TLS check interval | `12h` | +| `DNSWATCHER_DNS_INTERVAL` | DNS check interval, a positive duration such as `30m`; empty means the default, anything else stops startup | `1h` | +| `DNSWATCHER_TLS_INTERVAL` | TLS check interval, a positive duration such as `6h`; empty means the default, anything else stops startup | `12h` | | `DNSWATCHER_TLS_EXPIRY_WARNING` | Days before expiry to warn | `7` | | `DNSWATCHER_SENTRY_DSN` | Sentry DSN for error reporting | `""` | | `DNSWATCHER_MAINTENANCE_MODE` | Enable maintenance mode | `false` | @@ -344,6 +344,14 @@ the client address is taken from the `X-Real-IP` or `X-Forwarded-For` header the proxy sets; a proxy that sets neither makes all its clients share one allowance. +**`DNSWATCHER_DNS_INTERVAL` and `DNSWATCHER_TLS_INTERVAL`** take a positive +duration: a number followed by a unit such as `s`, `m` or `h`, for example +`90s`, `30m`, `1h` or `1h30m`. There is no unit for days; write `24h`. An +unset or empty variable (`DNSWATCHER_DNS_INTERVAL=`) means the default. If +either is set to anything else, including a bare number or a zero or negative +duration, dnswatcher refuses to start with an error naming the variable and +the value. + ### Example `.env` ```sh diff --git a/TODO.md b/TODO.md index 0b048af..2d00cb7 100644 --- a/TODO.md +++ b/TODO.md @@ -20,6 +20,8 @@ https://git.eeqj.de/sneak/dnswatcher/issues/104 # Completed Steps +- 2026-10-01: a `DNSWATCHER_DNS_INTERVAL` or `DNSWATCHER_TLS_INTERVAL` that is + not a positive duration stops startup; empty means the default (closes #177). - 2026-10-01: `/metrics` allows each client address 30 requests a minute, counted before Basic Auth, and answers 429 beyond that (closes #101). - 2026-10-01: the image built by `make docker` reports the `git describe` @@ -97,8 +99,6 @@ https://git.eeqj.de/sneak/dnswatcher/issues/104 - nameserver IP address changes: https://git.eeqj.de/sneak/dnswatcher/issues/105 - `DNSWATCHER_SENTRY_DSN` does nothing: https://git.eeqj.de/sneak/dnswatcher/issues/107 -- invalid DNS or TLS interval silently replaced by the default: - https://git.eeqj.de/sneak/dnswatcher/issues/177 - trial run of the finished image: https://git.eeqj.de/sneak/dnswatcher/issues/149 - 1.0 readiness: run it with a real config and read the logs: diff --git a/internal/config/config.go b/internal/config/config.go index 264b90b..8d58433 100644 --- a/internal/config/config.go +++ b/internal/config/config.go @@ -28,6 +28,13 @@ var ErrNoTargets = errors.New( "no monitoring targets configured: set DNSWATCHER_TARGETS environment variable", ) +// ErrInvalidInterval is returned when DNSWATCHER_DNS_INTERVAL or +// DNSWATCHER_TLS_INTERVAL is set but is not a positive duration. An empty +// value counts as unset and means the default. +var ErrInvalidInterval = errors.New( + "interval must be a positive duration such as 30m or 1h", +) + // Params contains dependencies for Config. type Params struct { fx.In @@ -125,18 +132,14 @@ func buildConfig( } } - dnsInterval, err := time.ParseDuration( - viper.GetString("DNS_INTERVAL"), - ) + dnsInterval, err := parseInterval("DNS_INTERVAL") if err != nil { - dnsInterval = defaultDNSInterval + return nil, err } - tlsInterval, err := time.ParseDuration( - viper.GetString("TLS_INTERVAL"), - ) + tlsInterval, err := parseInterval("TLS_INTERVAL") if err != nil { - tlsInterval = defaultTLSInterval + return nil, err } domains, hostnames, err := parseAndValidateTargets() @@ -168,6 +171,22 @@ func buildConfig( return cfg, nil } +// parseInterval reads the DNSWATCHER_-prefixed setting key as a duration. A +// value that does not parse, or is zero or negative, is an error naming the +// variable and the value; an unset variable has its default from setupViper. +func parseInterval(key string) (time.Duration, error) { + value := viper.GetString(key) + + interval, err := time.ParseDuration(value) + if err != nil || interval <= 0 { + return 0, fmt.Errorf( + "invalid DNSWATCHER_%s %q: %w", key, value, ErrInvalidInterval, + ) + } + + return interval, nil +} + func parseAndValidateTargets() ([]string, []string, error) { domains, hostnames, err := ClassifyTargets( parseCSV(viper.GetString("TARGETS")), diff --git a/internal/config/config_test.go b/internal/config/config_test.go index 2917818..c4471ff 100644 --- a/internal/config/config_test.go +++ b/internal/config/config_test.go @@ -1,6 +1,7 @@ package config_test import ( + "strconv" "testing" "time" @@ -113,33 +114,40 @@ func TestNew_OnlyEmptyCSVSegments(t *testing.T) { assert.ErrorIs(t, err, config.ErrNoTargets) } -func TestNew_InvalidDNSInterval_FallsBackToDefault(t *testing.T) { - viper.Reset() - t.Setenv("DNSWATCHER_TARGETS", "example.com") - t.Setenv("DNSWATCHER_DNS_INTERVAL", "banana") +// TestNew_InvalidIntervalStopsStartup checks values that must stop startup; +// TestNew_DefaultValues and TestNew_EmptyIntervalMeansDefault check that an +// unset or empty interval means the default. +func TestNew_InvalidIntervalStopsStartup(t *testing.T) { + variables := []string{"DNSWATCHER_DNS_INTERVAL", "DNSWATCHER_TLS_INTERVAL"} + values := []string{ + "banana", // not a duration + "5", // no unit + "1d", // days are not a unit time.ParseDuration knows + "0", // zero + "-1h", // negative + } - cfg, err := config.New(nil, newTestParams(t)) - require.NoError(t, err) - assert.Equal(t, time.Hour, cfg.DNSInterval, - "invalid DNS interval should fall back to 1h default") + for _, variable := range variables { + for _, value := range values { + t.Run(variable+"="+value, func(t *testing.T) { + viper.Reset() + t.Setenv("DNSWATCHER_TARGETS", "example.com") + t.Setenv(variable, value) + + _, err := config.New(nil, newTestParams(t)) + require.ErrorIs(t, err, config.ErrInvalidInterval) + require.ErrorContains(t, err, variable) + require.ErrorContains(t, err, strconv.Quote(value)) + }) + } + } } -func TestNew_InvalidTLSInterval_FallsBackToDefault(t *testing.T) { +func TestNew_EmptyIntervalMeansDefault(t *testing.T) { viper.Reset() t.Setenv("DNSWATCHER_TARGETS", "example.com") - t.Setenv("DNSWATCHER_TLS_INTERVAL", "notaduration") - - cfg, err := config.New(nil, newTestParams(t)) - require.NoError(t, err) - assert.Equal(t, 12*time.Hour, cfg.TLSInterval, - "invalid TLS interval should fall back to 12h default") -} - -func TestNew_BothIntervalsInvalid(t *testing.T) { - viper.Reset() - t.Setenv("DNSWATCHER_TARGETS", "example.com") - t.Setenv("DNSWATCHER_DNS_INTERVAL", "xyz") - t.Setenv("DNSWATCHER_TLS_INTERVAL", "abc") + t.Setenv("DNSWATCHER_DNS_INTERVAL", "") + t.Setenv("DNSWATCHER_TLS_INTERVAL", "") cfg, err := config.New(nil, newTestParams(t)) require.NoError(t, err) -- 2.54.0