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Refactor golangci-lint configuration and improve error handling

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- Updated .golangci.yml to enable default linters and refine suppression rules, enhancing code quality visibility.
- Improved error handling in cmd/root.go by explicitly discarding low-value error messages during fatal exits for consistency with errcheck posture.
- Added best-effort error handling in various locations across the codebase, ensuring that non-critical errors are logged without affecting overall functionality.
- Introduced a new writeMetricsText function to streamline metrics output, improving code clarity and maintainability.
This commit is contained in:
Justin Harms
2026-05-27 18:51:33 -05:00
parent feda55e225
commit 843772e9f7
6 changed files with 129 additions and 105 deletions
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steamcache/steamcache.go
+52 -44
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@@ -59,7 +59,7 @@ func NewServiceManager() *ServiceManager {
`Steam`,
},
}
sm.AddService(steamConfig)
_ = sm.AddService(steamConfig) // error impossible: hardcoded patterns are valid regexes (user-provided services validated in AddService)
return sm
}
@@ -362,7 +362,7 @@ func (sc *SteamCache) streamCachedResponse(w http.ResponseWriter, r *http.Reques
w.WriteHeader(http.StatusPartialContent)
// Send the range data
w.Write(rangeData)
_, _ = w.Write(rangeData) // client write error ignored (disconnect during range body send is not actionable)
logger.Logger.Info().
Str("cache_key", cacheKey).
@@ -397,7 +397,7 @@ func (sc *SteamCache) streamCachedResponse(w http.ResponseWriter, r *http.Reques
w.WriteHeader(statusCode)
// Stream the full response body
w.Write(bodyData)
_, _ = w.Write(bodyData) // client write error ignored (disconnect during full cached body send is not actionable)
logger.Logger.Info().
Str("cache_key", cacheKey).
@@ -1108,17 +1108,17 @@ func (sc *SteamCache) Run() error {
resp, err := sc.client.Get(sc.upstream)
if err != nil {
if resp != nil {
resp.Body.Close()
_ = resp.Body.Close() // best-effort body close on connectivity error path; primary err returned
}
logger.Logger.Error().Err(err).Str("upstream", sc.upstream).Msg("Failed upstream connectivity check")
return err
}
if resp.StatusCode != http.StatusOK {
resp.Body.Close()
_ = resp.Body.Close() // best-effort body close on non-OK status; primary error returned
logger.Logger.Error().Int("status_code", resp.StatusCode).Str("upstream", sc.upstream).Msg("Upstream connectivity check returned non-OK status")
return fmt.Errorf("upstream returned status %d", resp.StatusCode)
}
resp.Body.Close()
_ = resp.Body.Close() // best-effort; success path close before ListenAndServe
}
sc.server.Handler = sc
@@ -1143,7 +1143,7 @@ func (sc *SteamCache) Run() error {
}()
<-ctx.Done()
sc.server.Shutdown(ctx)
_ = sc.server.Shutdown(ctx) // shutdown error secondary (ListenAndServe already terminated or context done); logged elsewhere if fatal
sc.wg.Wait()
return nil
}
@@ -1226,6 +1226,39 @@ func (sc *SteamCache) ResetMetrics() {
sc.metrics.Reset()
}
// writeMetricsText emits the Prometheus-style text metrics to the ResponseWriter.
// All fmt.Fprintf errors are intentionally discarded via _ = : this is a best-effort
// read-only debug endpoint; client disconnects or write errors during metrics dump
// are not actionable (do not affect cache correctness or require retries).
func writeMetricsText(w http.ResponseWriter, stats *metrics.Stats) {
_, _ = fmt.Fprintf(w, "# SteamCache2 Metrics\n")
_, _ = fmt.Fprintf(w, "total_requests %d\n", stats.TotalRequests)
_, _ = fmt.Fprintf(w, "cache_hits %d\n", stats.CacheHits)
_, _ = fmt.Fprintf(w, "cache_misses %d\n", stats.CacheMisses)
_, _ = fmt.Fprintf(w, "cache_coalesced %d\n", stats.CacheCoalesced)
_, _ = fmt.Fprintf(w, "errors %d\n", stats.Errors)
_, _ = fmt.Fprintf(w, "rate_limited %d\n", stats.RateLimited)
_, _ = fmt.Fprintf(w, "upstream_errors %d\n", stats.UpstreamErrors)
_, _ = fmt.Fprintf(w, "cache_write_failures %d\n", stats.CacheWriteFailures)
_, _ = fmt.Fprintf(w, "memory_cache_hits %d\n", stats.MemoryCacheHits)
_, _ = fmt.Fprintf(w, "disk_cache_hits %d\n", stats.DiskCacheHits)
_, _ = fmt.Fprintf(w, "promotions %d\n", stats.Promotions)
_, _ = fmt.Fprintf(w, "evictions %d\n", stats.Evictions)
for svc, cnt := range stats.ServiceErrors {
_, _ = fmt.Fprintf(w, "service_errors{service=%q} %d\n", svc, cnt)
}
for svc, cnt := range stats.ServiceRequests {
_, _ = fmt.Fprintf(w, "service_requests{service=%q} %d\n", svc, cnt)
}
_, _ = fmt.Fprintf(w, "hit_rate %.4f\n", stats.HitRate)
_, _ = fmt.Fprintf(w, "avg_response_time_ms %.2f\n", float64(stats.AvgResponseTime.Nanoseconds())/1e6)
_, _ = fmt.Fprintf(w, "total_bytes_served %d\n", stats.TotalBytesServed)
_, _ = fmt.Fprintf(w, "total_bytes_cached %d\n", stats.TotalBytesCached)
_, _ = fmt.Fprintf(w, "memory_cache_size %d\n", stats.MemoryCacheSize)
_, _ = fmt.Fprintf(w, "disk_cache_size %d\n", stats.DiskCacheSize)
_, _ = fmt.Fprintf(w, "uptime_seconds %.2f\n", stats.Uptime.Seconds())
}
func (sc *SteamCache) ServeHTTP(w http.ResponseWriter, r *http.Request) {
clientIP := getClientIP(r, sc.trustedProxies)
@@ -1288,7 +1321,7 @@ func (sc *SteamCache) ServeHTTP(w http.ResponseWriter, r *http.Request) {
Msg("LanCache heartbeat request")
w.Header().Add("X-LanCache-Processed-By", "SteamCache2")
w.WriteHeader(http.StatusNoContent)
w.Write(nil)
_, _ = w.Write(nil) // client write error ignored (heartbeat path; nil write is no-op)
return
}
@@ -1297,32 +1330,7 @@ func (sc *SteamCache) ServeHTTP(w http.ResponseWriter, r *http.Request) {
stats := sc.GetMetrics()
w.Header().Set("Content-Type", "text/plain")
w.WriteHeader(http.StatusOK)
fmt.Fprintf(w, "# SteamCache2 Metrics\n")
fmt.Fprintf(w, "total_requests %d\n", stats.TotalRequests)
fmt.Fprintf(w, "cache_hits %d\n", stats.CacheHits)
fmt.Fprintf(w, "cache_misses %d\n", stats.CacheMisses)
fmt.Fprintf(w, "cache_coalesced %d\n", stats.CacheCoalesced)
fmt.Fprintf(w, "errors %d\n", stats.Errors)
fmt.Fprintf(w, "rate_limited %d\n", stats.RateLimited)
fmt.Fprintf(w, "upstream_errors %d\n", stats.UpstreamErrors)
fmt.Fprintf(w, "cache_write_failures %d\n", stats.CacheWriteFailures)
fmt.Fprintf(w, "memory_cache_hits %d\n", stats.MemoryCacheHits)
fmt.Fprintf(w, "disk_cache_hits %d\n", stats.DiskCacheHits)
fmt.Fprintf(w, "promotions %d\n", stats.Promotions)
fmt.Fprintf(w, "evictions %d\n", stats.Evictions)
for svc, cnt := range stats.ServiceErrors {
fmt.Fprintf(w, "service_errors{service=%q} %d\n", svc, cnt)
}
for svc, cnt := range stats.ServiceRequests {
fmt.Fprintf(w, "service_requests{service=%q} %d\n", svc, cnt)
}
fmt.Fprintf(w, "hit_rate %.4f\n", stats.HitRate)
fmt.Fprintf(w, "avg_response_time_ms %.2f\n", float64(stats.AvgResponseTime.Nanoseconds())/1e6)
fmt.Fprintf(w, "total_bytes_served %d\n", stats.TotalBytesServed)
fmt.Fprintf(w, "total_bytes_cached %d\n", stats.TotalBytesCached)
fmt.Fprintf(w, "memory_cache_size %d\n", stats.MemoryCacheSize)
fmt.Fprintf(w, "disk_cache_size %d\n", stats.DiskCacheSize)
fmt.Fprintf(w, "uptime_seconds %.2f\n", stats.Uptime.Seconds())
writeMetricsText(w, stats)
return
}
@@ -1371,7 +1379,7 @@ func (sc *SteamCache) ServeHTTP(w http.ResponseWriter, r *http.Request) {
// Try to serve from cache
file, err := sc.vfs.Open(cachePath)
if err == nil {
defer file.Close()
defer func() { _ = file.Close() }() // best-effort close of cache file reader; error secondary (data already read or connection issue)
// Read the entire cached file
cachedData, err := io.ReadAll(file)
@@ -1381,7 +1389,7 @@ func (sc *SteamCache) ServeHTTP(w http.ResponseWriter, r *http.Request) {
Str("url", urlPath).
Err(err).
Msg("Failed to read cached file - removing corrupted entry")
sc.vfs.Delete(cachePath)
_ = sc.vfs.Delete(cachePath) // best-effort cleanup of corrupt entry; failure non-fatal (logged)
} else {
// Deserialize using new format
cacheFile, err := deserializeCacheFile(cachedData)
@@ -1392,7 +1400,7 @@ func (sc *SteamCache) ServeHTTP(w http.ResponseWriter, r *http.Request) {
Str("url", urlPath).
Err(err).
Msg("Failed to deserialize cache file - removing corrupted entry")
sc.vfs.Delete(cachePath)
_ = sc.vfs.Delete(cachePath) // best-effort cleanup of corrupt entry; failure non-fatal (logged)
} else {
// Track cache hit metrics
sc.metrics.IncrementCacheHits()
@@ -1472,7 +1480,7 @@ func (sc *SteamCache) ServeHTTP(w http.ResponseWriter, r *http.Request) {
w.Header().Set("X-LanCache-Status", "HIT-COALESCED")
w.Header().Set("X-LanCache-Processed-By", "SteamCache2")
w.WriteHeader(coalescedReq.statusCode)
w.Write(responseData)
_, _ = w.Write(responseData) // client write error ignored (disconnect during coalesced response send is not actionable)
// Track coalesced cache hit metrics
sc.metrics.IncrementCacheCoalesced()
@@ -1573,7 +1581,7 @@ func (sc *SteamCache) ServeHTTP(w http.ResponseWriter, r *http.Request) {
logger.Logger.Error().Err(err).Str("url", req.URL.String()).Msg("Failed to fetch the requested URL")
if resp != nil {
resp.Body.Close()
_ = resp.Body.Close() // best-effort close on upstream fetch error; primary error logged/returned
}
// Complete coalesced request with error
if isNew {
@@ -1589,7 +1597,7 @@ func (sc *SteamCache) ServeHTTP(w http.ResponseWriter, r *http.Request) {
if resp.StatusCode != http.StatusOK {
logger.Logger.Error().Int("status_code", resp.StatusCode).Str("url", req.URL.String()).Msg("Failed to fetch the requested URL (non-OK status after retries)")
resp.Body.Close()
_ = resp.Body.Close() // best-effort close on non-OK upstream; primary error path
// Complete coalesced request with error
if isNew {
coalescedReq.complete(nil, fmt.Errorf("upstream returned status %d", resp.StatusCode))
@@ -1601,7 +1609,7 @@ func (sc *SteamCache) ServeHTTP(w http.ResponseWriter, r *http.Request) {
http.Error(w, "Failed to fetch the requested URL", http.StatusInternalServerError)
return
}
defer resp.Body.Close()
defer func() { _ = resp.Body.Close() }() // best-effort close for success upstream response body (standard handler cleanup)
// Fast path: Flexible lightweight validation for all files
// Multiple validation layers ensure data integrity without blocking legitimate Steam content
@@ -1716,7 +1724,7 @@ func (sc *SteamCache) ServeHTTP(w http.ResponseWriter, r *http.Request) {
// Stream the response body to client
w.WriteHeader(resp.StatusCode)
w.Write(bodyData)
_, _ = w.Write(bodyData) // client write error ignored (disconnect during MISS body send is not actionable)
// Track cache miss metrics
sc.metrics.IncrementCacheMisses()
@@ -1751,7 +1759,7 @@ func (sc *SteamCache) ServeHTTP(w http.ResponseWriter, r *http.Request) {
// Store the serialized cache data
cacheWriter, err := sc.vfs.Create(cachePath, int64(len(cacheData)))
if err == nil {
defer cacheWriter.Close()
defer func() { _ = cacheWriter.Close() }() // best-effort close of cache writer; errors on close (e.g. final sync) logged via prior write checks or non-fatal
// Write the serialized cache data
bytesWritten, cacheErr := cacheWriter.Write(cacheData)
@@ -1766,7 +1774,7 @@ func (sc *SteamCache) ServeHTTP(w http.ResponseWriter, r *http.Request) {
Msg("Cache write failed or incomplete - removing corrupted entry")
sc.metrics.IncrementCacheWriteFailures()
sc.metrics.IncrementServiceError("cache_write")
sc.vfs.Delete(cachePath)
_ = sc.vfs.Delete(cachePath) // best-effort removal of partial corrupt cache entry on write failure; non-fatal. Deferred cacheWriter.Close() (from earlier in block) runs after this on error unwind path (harmless per DiskFS design)
} else {
// Track successful cache write
sc.metrics.AddBytesCached(int64(len(cacheData)))