refactor: simplify S3 HTTP config to single parameter

Per maintainer feedback - only expose MaxIdleConnsPerHost since
it's the only setting that differs from Go defaults (2 → 100).
Other HTTP transport settings use sensible Go defaults.

Author: mevinbabuc

README.md

@@ -824,18 +824,8 @@ Usage of imagor:
   -s3-result-storage-endpoint string
         Optional S3 Storage Endpoint to override default
 
-  -s3-http-max-idle-conns int
-        S3 HTTP client max idle connections across all hosts (default 100)
   -s3-http-max-idle-conns-per-host int
-        S3 HTTP client max idle connections per host. Increase for high-throughput workloads (default 100)
-  -s3-http-max-conns-per-host int
-        S3 HTTP client max connections per host. 0 means unlimited (default 0)
-  -s3-http-idle-conn-timeout duration
-        S3 HTTP client idle connection timeout (default 90s)
-  -s3-http-response-header-timeout duration
-        S3 HTTP client response header timeout. 0 means no timeout (default 0)
-  -s3-http-disable-keep-alives
-        S3 HTTP client disable keep-alives. Not recommended for production
+        S3 HTTP client max idle connections per host (default 100, Go default is 2)
 
   -gcloud-safe-chars string
         Google Cloud safe characters to be excluded from image key escape. Set -- for no-op

config/awsconfig/awsconfig.go

@@ -98,18 +98,8 @@ func WithAWS(fs *flag.FlagSet, cb func() (*zap.Logger, bool)) imagor.Option {
 		s3StorageClass = fs.String("s3-storage-class", "STANDARD",
 			"S3 File Storage Class. Available values: REDUCED_REDUNDANCY, STANDARD_IA, ONEZONE_IA, INTELLIGENT_TIERING, GLACIER, DEEP_ARCHIVE. Default: STANDARD.")
 
-		s3HTTPMaxIdleConns = fs.Int("s3-http-max-idle-conns", 100,
-			"S3 HTTP client max idle connections across all hosts")
 		s3HTTPMaxIdleConnsPerHost = fs.Int("s3-http-max-idle-conns-per-host", 100,
-			"S3 HTTP client max idle connections per host. Increase for high-throughput workloads")
-		s3HTTPMaxConnsPerHost = fs.Int("s3-http-max-conns-per-host", 0,
-			"S3 HTTP client max connections per host. 0 means unlimited")
-		s3HTTPIdleConnTimeout = fs.Duration("s3-http-idle-conn-timeout", 90*time.Second,
-			"S3 HTTP client idle connection timeout")
-		s3HTTPResponseHeaderTimeout = fs.Duration("s3-http-response-header-timeout", 0,
-			"S3 HTTP client response header timeout. 0 means no timeout")
-		s3HTTPDisableKeepAlives = fs.Bool("s3-http-disable-keep-alives", false,
-			"S3 HTTP client disable keep-alives. Not recommended for production")
+			"S3 HTTP client max idle connections per host (Go default is 2, increase for high-throughput workloads)")
 
 		_, _ = cb()
 	)
@@ -120,14 +110,7 @@ func WithAWS(fs *flag.FlagSet, cb func() (*zap.Logger, bool)) imagor.Option {
 
 		ctx := context.Background()
 
-		httpClient := createHTTPClient(
-			*s3HTTPMaxIdleConns,
-			*s3HTTPMaxIdleConnsPerHost,
-			*s3HTTPMaxConnsPerHost,
-			*s3HTTPIdleConnTimeout,
-			*s3HTTPResponseHeaderTimeout,
-			*s3HTTPDisableKeepAlives,
-		)
+		httpClient := createHTTPClient(*s3HTTPMaxIdleConnsPerHost)
 
 		var loaderCfg, storageCfg, resultStorageCfg aws.Config
 		var err error
@@ -243,28 +226,18 @@ func WithAWS(fs *flag.FlagSet, cb func() (*zap.Logger, bool)) imagor.Option {
 	}
 }
 
-func createHTTPClient(
-	maxIdleConns int,
-	maxIdleConnsPerHost int,
-	maxConnsPerHost int,
-	idleConnTimeout time.Duration,
-	responseHeaderTimeout time.Duration,
-	disableKeepAlives bool,
-) *http.Client {
+func createHTTPClient(maxIdleConnsPerHost int) *http.Client {
 	transport := &http.Transport{
 		Proxy: http.ProxyFromEnvironment,
 		DialContext: (&net.Dialer{
 			Timeout:   30 * time.Second,
 			KeepAlive: 30 * time.Second,
 		}).DialContext,
-		MaxIdleConns:          maxIdleConns,
+		MaxIdleConns:          100,
 		MaxIdleConnsPerHost:   maxIdleConnsPerHost,
-		MaxConnsPerHost:       maxConnsPerHost,
-		IdleConnTimeout:       idleConnTimeout,
+		IdleConnTimeout:       90 * time.Second,
 		TLSHandshakeTimeout:   10 * time.Second,
 		ExpectContinueTimeout: 1 * time.Second,
-		ResponseHeaderTimeout: responseHeaderTimeout,
-		DisableKeepAlives:     disableKeepAlives,
 		ForceAttemptHTTP2:     true,
 	}