Port changes from #2334

I'm not sure I follow, but I trust @lifenjoiner

Fixes #2334

dnscrypt-proxy/config.go

@@ -631,7 +631,7 @@ func ConfigLoad(proxy *Proxy, flags *ConfigFlags) error {
 	proxy.anonDirectCertFallback = config.AnonymizedDNS.DirectCertFallback
 
 	if len(config.TLSKeyLogFile) > 0 {
-		f, err := os.OpenFile(config.TLSKeyLogFile, os.O_APPEND|os.O_CREATE|os.O_WRONLY, 0600)
+		f, err := os.OpenFile(config.TLSKeyLogFile, os.O_APPEND|os.O_CREATE|os.O_WRONLY, 0o600)
 		if err != nil {
 			dlog.Fatalf("Unable to create key log file [%s]: [%s]", config.TLSKeyLogFile, err)
 		}
@@ -892,8 +892,8 @@ func (config *Config) loadSource(proxy *Proxy, cfgSourceName string, cfgSource *
 	if cfgSource.FormatStr == "" {
 		cfgSource.FormatStr = "v2"
 	}
-	if cfgSource.RefreshDelay <= 0 {
-		cfgSource.RefreshDelay = 72
+	if cfgSource.RefreshDelay < 24 {
+		cfgSource.RefreshDelay = 24
 	} else if cfgSource.RefreshDelay > 168 {
 		cfgSource.RefreshDelay = 168
 	}

dnscrypt-proxy/example-dnscrypt-proxy.toml

@@ -696,9 +696,9 @@ format = 'tsv'
 ## If the `urls` property is missing, cache files and valid signatures
 ## must already be present. This doesn't prevent these cache files from
 ## expiring after `refresh_delay` hours.
-## Cache freshness is checked every 24 hours, so values for 'refresh_delay'
-## of less than 24 hours will have no effect.
-## A maximum delay of 168 hours (1 week) is imposed to ensure cache freshness.
+## `refreshed_delay` must be in the [24..168] interval.
+## The minimum delay of 24 hours (1 day) avoids unnecessary requests to servers.
+## The maximum delay of 168 hours (1 week) ensures cache freshness.
 
 [sources]
 

dnscrypt-proxy/sources.go

@@ -23,21 +23,18 @@ const (
 	SourceFormatV2 = iota
 )
 
-const (
-	DefaultPrefetchDelay    time.Duration = 24 * time.Hour
-	MinimumPrefetchInterval time.Duration = 10 * time.Minute
-)
+const MinimumPrefetchInterval time.Duration = 10 * time.Minute
 
 type Source struct {
-	name                    string
-	urls                    []*url.URL
-	bin                     []byte // copy of the file content - there's something wrong in our logic, we shouldn't need to keep that in memory
-	minisignKey             *minisign.PublicKey
-	cacheFile               string
-	prefix                  string
-	cacheTTL, prefetchDelay time.Duration
-	refresh                 time.Time
-	format                  SourceFormat
+	name        string
+	urls        []*url.URL
+	bin         []byte // copy of the file content - there's something wrong in our logic, we shouldn't need to keep that in memory
+	minisignKey *minisign.PublicKey
+	cacheFile   string
+	prefix      string
+	cacheTTL    time.Duration
+	refresh     time.Time
+	format      SourceFormat
 }
 
 func (source *Source) checkSignature(bin, sig []byte) (err error) {
@@ -68,8 +65,8 @@ func (source *Source) fetchFromCache(now time.Time) (remaining time.Duration, er
 		return
 	}
 	if elapsed := now.Sub(fi.ModTime()); elapsed < source.cacheTTL {
-		remaining = source.prefetchDelay - elapsed
-		dlog.Debugf("Source [%s] cache file [%s] is still fresh, next update: %v min", source.name, source.cacheFile, math.Round(remaining.Minutes()))
+		remaining = source.cacheTTL - elapsed
+		dlog.Debugf("Source [%s] cache file [%s] is still fresh, next update in %v min", source.name, source.cacheFile, math.Round(remaining.Minutes()))
 	} else {
 		dlog.Debugf("Source [%s] cache file [%s] needs to be refreshed", source.name, source.cacheFile)
 	}
@@ -174,7 +171,7 @@ func (source *Source) fetchWithCache(xTransport *XTransport, now time.Time) (tim
 		return MinimumPrefetchInterval, err
 	}
 	source.updateCache(bin, sig, now)
-	remaining = source.prefetchDelay
+	remaining = source.cacheTTL
 	source.refresh = now.Add(remaining)
 	return remaining, nil
 }
@@ -190,16 +187,12 @@ func NewSource(
 	refreshDelay time.Duration,
 	prefix string,
 ) (source *Source, err error) {
-	if refreshDelay < DefaultPrefetchDelay {
-		refreshDelay = DefaultPrefetchDelay
-	}
 	source = &Source{
-		name:          name,
-		urls:          []*url.URL{},
-		cacheFile:     cacheFile,
-		cacheTTL:      refreshDelay,
-		prefetchDelay: DefaultPrefetchDelay,
-		prefix:        prefix,
+		name:      name,
+		urls:      []*url.URL{},
+		cacheFile: cacheFile,
+		cacheTTL:  refreshDelay,
+		prefix:    prefix,
 	}
 	if formatStr == "v2" {
 		source.format = SourceFormatV2

dnscrypt-proxy/sources_test.go

@@ -42,6 +42,8 @@ const (
 	TestStatePathErr                           // unparseable path to files (download only)
 )
 
+const DefaultPrefetchDelay time.Duration = 24 * time.Hour
+
 type SourceTestData struct {
 	n                         int // subtest counter
 	xTransport                *XTransport
@@ -350,7 +352,7 @@ func prepSourceTestDownload(
 	}
 	if e.success {
 		e.err = ""
-		e.delay = DefaultPrefetchDelay
+		e.delay = e.Source.cacheTTL
 	} else {
 		e.delay = MinimumPrefetchInterval
 	}
@@ -371,7 +373,7 @@ func setupSourceTestCase(t *testing.T, d *SourceTestData, i int,
 	}
 	e.Source = &Source{
 		name: id, urls: []*url.URL{}, format: SourceFormatV2, minisignKey: d.key,
-		cacheFile: e.cachePath, cacheTTL: DefaultPrefetchDelay * 3, prefetchDelay: DefaultPrefetchDelay,
+		cacheFile: e.cachePath, cacheTTL: DefaultPrefetchDelay * 3,
 	}
 	if cacheTest != nil {
 		prepSourceTestCache(t, d, e, d.sources[i], *cacheTest)
@@ -405,9 +407,9 @@ func TestNewSource(t *testing.T) {
 		refreshDelay time.Duration
 		e            *SourceTestExpect
 	}{
-		{"", "", 0, &SourceTestExpect{err: " ", Source: &Source{name: "short refresh delay", urls: []*url.URL{}, cacheTTL: DefaultPrefetchDelay, prefetchDelay: DefaultPrefetchDelay, prefix: ""}}},
-		{"v1", d.keyStr, DefaultPrefetchDelay * 2, &SourceTestExpect{err: "Unsupported source format", Source: &Source{name: "old format", urls: []*url.URL{}, cacheTTL: DefaultPrefetchDelay * 2, prefetchDelay: DefaultPrefetchDelay}}},
-		{"v2", "", DefaultPrefetchDelay * 3, &SourceTestExpect{err: "Invalid encoded public key", Source: &Source{name: "invalid public key", urls: []*url.URL{}, cacheTTL: DefaultPrefetchDelay * 3, prefetchDelay: DefaultPrefetchDelay}}},
+		{"", "", 0, &SourceTestExpect{err: " ", Source: &Source{name: "short refresh delay", urls: []*url.URL{}, cacheTTL: DefaultPrefetchDelay, prefix: ""}}},
+		{"v1", d.keyStr, DefaultPrefetchDelay * 2, &SourceTestExpect{err: "Unsupported source format", Source: &Source{name: "old format", urls: []*url.URL{}, cacheTTL: DefaultPrefetchDelay * 2}}},
+		{"v2", "", DefaultPrefetchDelay * 3, &SourceTestExpect{err: "Invalid encoded public key", Source: &Source{name: "invalid public key", urls: []*url.URL{}, cacheTTL: DefaultPrefetchDelay * 3}}},
 	} {
 		t.Run(tt.e.Source.name, func(t *testing.T) {
 			got, err := NewSource(
@@ -478,6 +480,7 @@ func TestPrefetchSources(t *testing.T) {
 			s := &Source{}
 			*s = *e.Source
 			s.bin = nil
+			s.refresh = d.timeNow
 			sources = append(sources, s)
 			expects = append(expects, e)
 		}