Add ability to disable compression for thruster by env variable

README.md

@@ -73,25 +73,26 @@ configuration. But if you need to customize its behavior, there are a few
 environment variables that you can set.
 
 | Variable Name         | Description                                             | Default Value |
-|-----------------------|---------------------------------------------------------|---------------|
-| `TLS_DOMAIN`          | Comma-separated list of domain names to use for TLS provisioning. If not set, TLS will be disabled. | None |
-| `TARGET_PORT`         | The port that your Puma server should run on. Thruster will set `PORT` to this value when starting your server. | 3000 |
-| `CACHE_SIZE`          | The size of the HTTP cache in bytes. | 64MB |
-| `MAX_CACHE_ITEM_SIZE` | The maximum size of a single item in the HTTP cache in bytes. | 1MB |
-| `X_SENDFILE_ENABLED`  | Whether to enable X-Sendfile support. Set to `0` or `false` to disable. | Enabled |
-| `MAX_REQUEST_BODY`    | The maximum size of a request body in bytes. Requests larger than this size will be refused; `0` means no maximum size is enforced. | `0` |
-| `STORAGE_PATH`        | The path to store Thruster's internal state. Provisioned TLS certificates will be stored here, so that they will not need to be requested every time your application is started. | `./storage/thruster` |
-| `BAD_GATEWAY_PAGE`    | Path to an HTML file to serve when the backend server returns a 502 Bad Gateway error. If there is no file at the specific path, Thruster will serve an empty 502 response instead. Because Thruster boots very quickly, a custom page can be a useful way to show that your application is starting up. | `./public/502.html` |
-| `HTTP_PORT`           | The port to listen on for HTTP traffic. | 80 |
-| `HTTPS_PORT`          | The port to listen on for HTTPS traffic. | 443 |
-| `HTTP_IDLE_TIMEOUT`   | The maximum time in seconds that a client can be idle before the connection is closed. | 60 |
-| `HTTP_READ_TIMEOUT`   | The maximum time in seconds that a client can take to send the request headers and body. | 30 |
-| `HTTP_WRITE_TIMEOUT`  | The maximum time in seconds during which the client must read the response. | 30 |
-| `ACME_DIRECTORY`      | The URL of the ACME directory to use for TLS certificate provisioning. | `https://acme-v02.api.letsencrypt.org/directory` (Let's Encrypt production) |
-| `EAB_KID`             | The EAB key identifier to use when provisioning TLS certificates, if required. | None |
-| `EAB_HMAC_KEY`        | The Base64-encoded EAB HMAC key to use when provisioning TLS certificates, if required. | None |
-| `FORWARD_HEADERS`     | Whether to forward X-Forwarded-* headers from the client. | Disabled when running with TLS; enabled otherwise |
-| `DEBUG`               | Set to `1` or `true` to enable debug logging. | Disabled |
+|-----------------------------|---------------------------------------------------------|---------------|
+| `TLS_DOMAIN`                | Comma-separated list of domain names to use for TLS provisioning. If not set, TLS will be disabled. | None |
+| `TARGET_PORT`               | The port that your Puma server should run on. Thruster will set `PORT` to this value when starting your server. | 3000 |
+| `CACHE_SIZE`                | The size of the HTTP cache in bytes. | 64MB |
+| `MAX_CACHE_ITEM_SIZE`       | The maximum size of a single item in the HTTP cache in bytes. | 1MB |
+| `GZIP_COMPRESSION_ENABLED`  | Whether to enable gzip compression for static assets. Set to `0` or `false` to disable. | Enabled |
+| `X_SENDFILE_ENABLED`        | Whether to enable X-Sendfile support. Set to `0` or `false` to disable. | Enabled |
+| `MAX_REQUEST_BODY`          | The maximum size of a request body in bytes. Requests larger than this size will be refused; `0` means no maximum size is enforced. | `0` |
+| `STORAGE_PATH`              | The path to store Thruster's internal state. Provisioned TLS certificates will be stored here, so that they will not need to be requested every time your application is started. | `./storage/thruster` |
+| `BAD_GATEWAY_PAGE`          | Path to an HTML file to serve when the backend server returns a 502 Bad Gateway error. If there is no file at the specific path, Thruster will serve an empty 502 response instead. Because Thruster boots very quickly, a custom page can be a useful way to show that your application is starting up. | `./public/502.html` |
+| `HTTP_PORT`                 | The port to listen on for HTTP traffic. | 80 |
+| `HTTPS_PORT`                | The port to listen on for HTTPS traffic. | 443 |
+| `HTTP_IDLE_TIMEOUT`         | The maximum time in seconds that a client can be idle before the connection is closed. | 60 |
+| `HTTP_READ_TIMEOUT`         | The maximum time in seconds that a client can take to send the request headers and body. | 30 |
+| `HTTP_WRITE_TIMEOUT`        | The maximum time in seconds during which the client must read the response. | 30 |
+| `ACME_DIRECTORY`            | The URL of the ACME directory to use for TLS certificate provisioning. | `https://acme-v02.api.letsencrypt.org/directory` (Let's Encrypt production) |
+| `EAB_KID`                   | The EAB key identifier to use when provisioning TLS certificates, if required. | None |
+| `EAB_HMAC_KEY`              | The Base64-encoded EAB HMAC key to use when provisioning TLS certificates, if required. | None |
+| `FORWARD_HEADERS`           | Whether to forward X-Forwarded-* headers from the client. | Disabled when running with TLS; enabled otherwise |
+| `DEBUG`                     | Set to `1` or `true` to enable debug logging. | Disabled |
 
 To prevent naming clashes with your application's own environment variables,
 Thruster's environment variables can optionally be prefixed with `THRUSTER_`.

internal/config.go

@@ -41,10 +41,11 @@ type Config struct {
 	UpstreamCommand string
 	UpstreamArgs    []string
 
-	CacheSizeBytes        int
-	MaxCacheItemSizeBytes int
-	XSendfileEnabled      bool
-	MaxRequestBody        int
+	CacheSizeBytes         int
+	MaxCacheItemSizeBytes  int
+	XSendfileEnabled       bool
+	GzipCompressionEnabled bool
+	MaxRequestBody         int
 
 	TLSDomains       []string
 	ACMEDirectoryURL string
@@ -79,10 +80,11 @@ func NewConfig() (*Config, error) {
 		UpstreamCommand: os.Args[1],
 		UpstreamArgs:    os.Args[2:],
 
-		CacheSizeBytes:        getEnvInt("CACHE_SIZE", defaultCacheSize),
-		MaxCacheItemSizeBytes: getEnvInt("MAX_CACHE_ITEM_SIZE", defaultMaxCacheItemSizeBytes),
-		XSendfileEnabled:      getEnvBool("X_SENDFILE_ENABLED", true),
-		MaxRequestBody:        getEnvInt("MAX_REQUEST_BODY", defaultMaxRequestBody),
+		CacheSizeBytes:         getEnvInt("CACHE_SIZE", defaultCacheSize),
+		MaxCacheItemSizeBytes:  getEnvInt("MAX_CACHE_ITEM_SIZE", defaultMaxCacheItemSizeBytes),
+		XSendfileEnabled:       getEnvBool("X_SENDFILE_ENABLED", true),
+		GzipCompressionEnabled: getEnvBool("GZIP_COMPRESSION_ENABLED", true),
+		MaxRequestBody:         getEnvInt("MAX_REQUEST_BODY", defaultMaxRequestBody),
 
 		TLSDomains:       getEnvStrings("TLS_DOMAIN", []string{}),
 		ACMEDirectoryURL: getEnvString("ACME_DIRECTORY", defaultACMEDirectoryURL),

internal/config_test.go

@@ -113,6 +113,7 @@ func TestConfig_override_defaults_with_env_vars(t *testing.T) {
 	usingEnvVar(t, "CACHE_SIZE", "256")
 	usingEnvVar(t, "HTTP_READ_TIMEOUT", "5")
 	usingEnvVar(t, "X_SENDFILE_ENABLED", "0")
+	usingEnvVar(t, "GZIP_COMPRESSION_ENABLED", "0")
 	usingEnvVar(t, "DEBUG", "1")
 	usingEnvVar(t, "ACME_DIRECTORY", "https://acme-staging-v02.api.letsencrypt.org/directory")
 
@@ -123,6 +124,7 @@ func TestConfig_override_defaults_with_env_vars(t *testing.T) {
 	assert.Equal(t, 256, c.CacheSizeBytes)
 	assert.Equal(t, 5*time.Second, c.HttpReadTimeout)
 	assert.Equal(t, false, c.XSendfileEnabled)
+	assert.Equal(t, false, c.GzipCompressionEnabled)
 	assert.Equal(t, slog.LevelDebug, c.LogLevel)
 	assert.Equal(t, "https://acme-staging-v02.api.letsencrypt.org/directory", c.ACMEDirectoryURL)
 }

internal/handler.go

@@ -15,14 +15,17 @@ type HandlerOptions struct {
 	maxRequestBody           int
 	targetUrl                *url.URL
 	xSendfileEnabled         bool
+	gzipCompressionEnabled   bool
 	forwardHeaders           bool
 }
 
 func NewHandler(options HandlerOptions) http.Handler {
 	handler := NewProxyHandler(options.targetUrl, options.badGatewayPage, options.forwardHeaders)
 	handler = NewCacheHandler(options.cache, options.maxCacheableResponseBody, handler)
 	handler = NewSendfileHandler(options.xSendfileEnabled, handler)
-	handler = gzhttp.GzipHandler(handler)
+	if options.gzipCompressionEnabled {
+		handler = gzhttp.GzipHandler(handler)
+	}
 
 	if options.maxRequestBody > 0 {
 		handler = http.MaxBytesHandler(handler, int64(options.maxRequestBody))

internal/handler_test.go

@@ -33,6 +33,30 @@ func TestHandlerGzipCompression_when_proxying(t *testing.T) {
 	assert.Less(t, transferredSize, fixtureLength("loremipsum.txt"))
 }
 
+func TestNotHandlerGzipCompression_when_disabled(t *testing.T) {
+	fixtureLength := strconv.FormatInt(fixtureLength("loremipsum.txt"), 10)
+
+	upstream := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		w.Header().Set("Content-Length", fixtureLength)
+		w.Write(fixtureContent("loremipsum.txt"))
+	}))
+	defer upstream.Close()
+
+	options := handlerOptions(upstream.URL)
+	options.gzipCompressionEnabled = false
+	h := NewHandler(options)
+
+	w := httptest.NewRecorder()
+	r := httptest.NewRequest("GET", "/", nil)
+	r.Header.Set("Accept-Encoding", "gzip")
+	h.ServeHTTP(w, r)
+
+	assert.Equal(t, http.StatusOK, w.Code)
+	assert.Contains(t, w.Header().Get("Content-Type"), "text/plain")
+	assert.Empty(t, w.Header().Get("Content-Encoding"))
+	assert.Equal(t, fixtureLength, w.Header().Get("Content-Length"))
+}
+
 func TestHandlerGzipCompression_is_not_applied_when_not_requested(t *testing.T) {
 	fixtureLength := strconv.FormatInt(fixtureLength("loremipsum.txt"), 10)
 
@@ -248,6 +272,7 @@ func handlerOptions(targetUrl string) HandlerOptions {
 		cache:                    NewMemoryCache(defaultCacheSize, defaultMaxCacheItemSizeBytes),
 		targetUrl:                url,
 		xSendfileEnabled:         true,
+		gzipCompressionEnabled:   true,
 		maxCacheableResponseBody: 1024,
 		badGatewayPage:           "",
 		forwardHeaders:           true,

internal/service.go

@@ -22,6 +22,7 @@ func (s *Service) Run() int {
 		cache:                    s.cache(),
 		targetUrl:                s.targetUrl(),
 		xSendfileEnabled:         s.config.XSendfileEnabled,
+		gzipCompressionEnabled:   s.config.GzipCompressionEnabled,
 		maxCacheableResponseBody: s.config.MaxCacheItemSizeBytes,
 		maxRequestBody:           s.config.MaxRequestBody,
 		badGatewayPage:           s.config.BadGatewayPage,