Rename concurrency to workers

CHANGELOG.md

@@ -3,6 +3,7 @@
 ## [Unreleased]
 ### Add
 - Add [multi-region mode](https://docs.imgproxy.net/latest/serving_files_from_s3?id=multi-region-mode) to S3 integration.
+- Add `IMGPROXY_WORKERS` alias for the `IMGPROXY_CONCURRENCY` config.
 
 ### Change
 - Don't report `The image request is cancelled` errors.
@@ -10,8 +11,6 @@
 
 ### Fix
 - Fix reporting image loading errors.
-
-### Fix
 - Fix the `Cache-Control` and `Expires` headers behavior when both `IMGPROXY_CACHE_CONTROL_PASSTHROUGH` and `IMGPROXY_FALLBACK_IMAGE_TTL` configs are set.
 - (pro) Fix the `IMGPROXY_FALLBACK_IMAGE_TTL` config behavior when the `fallback_image_url` processing option is used.
 

config/config.go

@@ -26,7 +26,7 @@ var (
 	KeepAliveTimeout       int
 	ClientKeepAliveTimeout int
 	DownloadTimeout        int
-	Concurrency            int
+	Workers                int
 	RequestsQueueSize      int
 	MaxClients             int
 
@@ -219,7 +219,7 @@ func Reset() {
 	KeepAliveTimeout = 10
 	ClientKeepAliveTimeout = 90
 	DownloadTimeout = 5
-	Concurrency = runtime.GOMAXPROCS(0) * 2
+	Workers = runtime.GOMAXPROCS(0) * 2
 	RequestsQueueSize = 0
 	MaxClients = 2048
 
@@ -400,7 +400,8 @@ func Configure() error {
 	configurators.Int(&KeepAliveTimeout, "IMGPROXY_KEEP_ALIVE_TIMEOUT")
 	configurators.Int(&ClientKeepAliveTimeout, "IMGPROXY_CLIENT_KEEP_ALIVE_TIMEOUT")
 	configurators.Int(&DownloadTimeout, "IMGPROXY_DOWNLOAD_TIMEOUT")
-	configurators.Int(&Concurrency, "IMGPROXY_CONCURRENCY")
+	configurators.Int(&Workers, "IMGPROXY_CONCURRENCY")
+	configurators.Int(&Workers, "IMGPROXY_WORKERS")
 	configurators.Int(&RequestsQueueSize, "IMGPROXY_REQUESTS_QUEUE_SIZE")
 	configurators.Int(&MaxClients, "IMGPROXY_MAX_CLIENTS")
 
@@ -625,8 +626,8 @@ func Configure() error {
 		return fmt.Errorf("Download timeout should be greater than 0, now - %d\n", DownloadTimeout)
 	}
 
-	if Concurrency <= 0 {
+	if Workers <= 0 {
-		return fmt.Errorf("Concurrency should be greater than 0, now - %d\n", Concurrency)
+		return fmt.Errorf("Workers number should be greater than 0, now - %d\n", Workers)
 	}
 
 	if RequestsQueueSize < 0 {
@@ -634,7 +635,7 @@ func Configure() error {
 	}
 
 	if MaxClients < 0 {
-		return fmt.Errorf("Concurrency should be greater than or equal 0, now - %d\n", MaxClients)
+		return fmt.Errorf("Max clients number should be greater than or equal 0, now - %d\n", MaxClients)
 	}
 
 	if TTL <= 0 {

docs/cloud_watch.md

@@ -11,7 +11,7 @@ imgproxy sends the following metrics to CloudWatch:
 
 * `RequestsInProgress`: the number of requests currently in progress
 * `ImagesInProgress`: the number of images currently in progress
-* `ConcurrencyUtilization`: the percentage of imgproxy's concurrency utilization. Calculated as `RequestsInProgress / IMGPROXY_CONCURRENCY * 100`
+* `WorkersUtilization`, `ConcurrencyUtilization`: the percentage of imgproxy's workers utilization. Calculated as `RequestsInProgress / IMGPROXY_WORKERS * 100`
 * `BufferSize`: a summary of the download buffers sizes (in bytes)
 * `BufferDefaultSize`: calibrated default buffer size (in bytes)
 * `BufferMaxSize`: calibrated maximum buffer size (in bytes)

docs/configuration.md

@@ -33,7 +33,7 @@ echo $(xxd -g 2 -l 64 -p /dev/random | tr -d '\n')
 * `IMGPROXY_KEEP_ALIVE_TIMEOUT`: the maximum duration (in seconds) to wait for the next request before closing the connection. When set to `0`, keep-alive is disabled. Default: `10`
 * `IMGPROXY_CLIENT_KEEP_ALIVE_TIMEOUT`: the maximum duration (in seconds) to wait for the next request before closing the HTTP client connection. The HTTP client is used to download source images. When set to `0`, keep-alive is disabled. Default: `90`
 * `IMGPROXY_DOWNLOAD_TIMEOUT`: the maximum duration (in seconds) for downloading the source image. Default: `5`
-* `IMGPROXY_CONCURRENCY`: the maximum number of image requests to be processed simultaneously. Requests that exceed this limit are put in the queue. Default: the number of CPU cores multiplied by two
+* `IMGPROXY_WORKERS`: _(alias: `IMGPROXY_CONCURRENCY`)_ the maximum number of images an imgproxy instance can process simultaneously without creating a queue. Default: the number of CPU cores multiplied by two
 * `IMGPROXY_REQUESTS_QUEUE_SIZE`: the maximum number of image requests that can be put in the queue. Requests that exceed this limit are rejected with `429` HTTP status. When set to `0`, the requests queue is unlimited. Default: `0`
 * `IMGPROXY_MAX_CLIENTS`: the maximum number of simultaneous active connections. When set to `0`, connection limit is disabled. Default: `2048`
 * `IMGPROXY_TTL`: a duration (in seconds) sent via the `Expires` and `Cache-Control: max-age` HTTP headers. Default: `31536000` (1 year)

docs/generating_the_url.md

@@ -746,7 +746,7 @@ When set to `1`, `t` or `true`, imgproxy will respond with a raw unprocessed, an
 * While the `skip_processing` option has some conditions to skip the processing, the `raw` option allows to skip processing no matter what
 * With the `raw` option set, imgproxy doesn't check the source image's type, resolution, and file size. Basically, the `raw` option allows streaming of any file type
 * With the `raw` option set, imgproxy won't download the whole image to the memory. Instead, it will stream the source image directly to the response lowering memory usage
-* The requests with the `raw` option set are not limited by the `IMGPROXY_CONCURRENCY` config
+* The requests with the `raw` option set are not limited by the `IMGPROXY_WORKERS` config
 
 Default: `false`
 

imagedata/read.go

@@ -18,7 +18,7 @@ var ErrSourceImageTypeNotSupported = ierrors.New(422, "Source image type not sup
 var downloadBufPool *bufpool.Pool
 
 func initRead() {
-	downloadBufPool = bufpool.New("download", config.Concurrency, config.DownloadBufferSize)
+	downloadBufPool = bufpool.New("download", config.Workers, config.DownloadBufferSize)
 }
 
 func readAndCheckImage(r io.Reader, contentLength int, secopts security.Options) (*ImageData, error) {

metrics/cloudwatch/cloudwatch.go

@@ -232,7 +232,16 @@ func runMetricsCollector() {
 				MetricName: aws.String("ConcurrencyUtilization"),
 				Unit:       aws.String("Percent"),
 				Value: aws.Float64(
-					stats.RequestsInProgress() / float64(config.Concurrency) * 100.0,
+					stats.RequestsInProgress() / float64(config.Workers) * 100.0,
+				),
+			})
+
+			metrics = append(metrics, &cloudwatch.MetricDatum{
+				Dimensions: []*cloudwatch.Dimension{dimension},
+				MetricName: aws.String("WorkersUtilization"),
+				Unit:       aws.String("Percent"),
+				Value: aws.Float64(
+					stats.RequestsInProgress() / float64(config.Workers) * 100.0,
 				),
 			})
 

processing_handler.go

@@ -37,10 +37,10 @@ var (
 
 func initProcessingHandler() {
 	if config.RequestsQueueSize > 0 {
-		queueSem = semaphore.New(config.RequestsQueueSize + config.Concurrency)
+		queueSem = semaphore.New(config.RequestsQueueSize + config.Workers)
 	}
 
-	processingSem = semaphore.New(config.Concurrency)
+	processingSem = semaphore.New(config.Workers)
 
 	vary := make([]string, 0)
 
@@ -282,7 +282,7 @@ func handleProcessing(reqID string, rw http.ResponseWriter, r *http.Request) {
 		}
 	}
 
-	// The heavy part start here, so we need to restrict concurrency
+	// The heavy part start here, so we need to restrict workers number
 	var processingSemToken *semaphore.Token
 	func() {
 		defer metrics.StartQueueSegment(ctx)()

transport/transport.go

@@ -30,7 +30,7 @@ func New(verifyNetworks bool) (*http.Transport, error) {
 		Proxy:                 http.ProxyFromEnvironment,
 		DialContext:           dialer.DialContext,
 		MaxIdleConns:          100,
-		MaxIdleConnsPerHost:   config.Concurrency + 1,
+		MaxIdleConnsPerHost:   config.Workers + 1,
 		IdleConnTimeout:       time.Duration(config.ClientKeepAliveTimeout) * time.Second,
 		TLSHandshakeTimeout:   10 * time.Second,
 		ExpectContinueTimeout: 1 * time.Second,