added unauthorized_user field in vmauth users config (#4083) (#4157)

added `unauthorized_user` field in vmauth users config (#4083)

---------

Signed-off-by: Alexander Marshalov <_@marshalov.org>

app/vmauth/README.md

@@ -62,6 +62,10 @@ The following [metrics](#monitoring) related to concurrency limits are exposed b
 - `vmauth_user_concurrent_requests_current{username="..."}` - the current number of concurrent requests for the given `username`.
 - `vmauth_user_concurrent_requests_limit_reached_total{username="foo"}` - the number of requests rejected with `429 Too Many Requests` error
   because of the concurrency limit has been reached for the given `username`.
+- `vmauth_unauthorized_user_concurrent_requests_capacity` - the limit on the number of concurrent requests for unauthorized users (if `unauthorized_user` section is used).
+- `vmauth_unauthorized_user_concurrent_requests_current` - the current number of concurrent requests for unauthorized users (if `unauthorized_user` section is used).
+- `vmauth_unauthorized_user_concurrent_requests_limit_reached_total` - the number of requests rejected with `429 Too Many Requests` error
+  because of the concurrency limit has been reached for unauthorized users (if `unauthorized_user` section is used).
 
 
 ## Auth config
@@ -152,6 +156,18 @@ users:
     url_prefix: "http://vminsert:8480/insert/42/prometheus"
     headers:
     - "X-Scope-OrgID: abc"
+
+# This requests will be executed for requests without Authorization header.
+# For instance, http://vmauth:8427/api/v1/query will be proxied to http://vmselect1:8481/select/0/prometheus/api/v1/query
+unauthorized_user:
+  url_map:
+    - src_paths:
+        - /health
+        - /api/v1/query/
+        - /api/v1/query_range
+      url_prefix:
+        - http://vmselect1:8481/select/0/prometheus
+        - http://vmselect2:8481/select/0/prometheus
 ```
 
 The config may contain `%{ENV_VAR}` placeholders, which are substituted by the corresponding `ENV_VAR` environment variable values.
@@ -194,6 +210,8 @@ users:
   # other config options here
 ```
 
+For unauthorized users `vmauth` exports `vmauth_unauthorized_user_requests_total` metric without label (if `unauthorized_user` section of config is used).
+
 ## How to build from sources
 
 It is recommended using [binary releases](https://github.com/VictoriaMetrics/VictoriaMetrics/releases) - `vmauth` is located in `vmutils-*` archives there.

app/vmauth/auth_config.go

@@ -32,6 +32,7 @@ var (
 // AuthConfig represents auth config.
 type AuthConfig struct {
 	Users            []UserInfo `yaml:"users,omitempty"`
+	UnauthorizedUser *UserInfo  `yaml:"unauthorized_user,omitempty"`
 }
 
 // UserInfo is user information read from authConfigPath
@@ -374,6 +375,18 @@ func parseAuthConfig(data []byte) (*AuthConfig, error) {
 	if err = yaml.UnmarshalStrict(data, &ac); err != nil {
 		return nil, fmt.Errorf("cannot unmarshal AuthConfig data: %w", err)
 	}
+	ui := ac.UnauthorizedUser
+	if ui != nil {
+		ui.requests = metrics.GetOrCreateCounter(`vmauth_unauthorized_user_requests_total`)
+		ui.concurrencyLimitCh = make(chan struct{}, ui.getMaxConcurrentRequests())
+		ui.concurrencyLimitReached = metrics.GetOrCreateCounter(`vmauth_unauthorized_user_concurrent_requests_limit_reached_total`)
+		_ = metrics.GetOrCreateGauge(`vmauth_unauthorized_user_concurrent_requests_capacity`, func() float64 {
+			return float64(cap(ui.concurrencyLimitCh))
+		})
+		_ = metrics.GetOrCreateGauge(`vmauth_unauthorized_user_concurrent_requests_current`, func() float64 {
+			return float64(len(ui.concurrencyLimitCh))
+		})
+	}
 	return &ac, nil
 }
 

app/vmauth/main.go

@@ -84,6 +84,13 @@ func requestHandler(w http.ResponseWriter, r *http.Request) bool {
 	}
 	authToken := r.Header.Get("Authorization")
 	if authToken == "" {
+		// Process requests for unauthorized users
+		ui := authConfig.Load().UnauthorizedUser
+		if ui != nil {
+			processUserRequest(w, r, ui)
+			return true
+		}
+
 		w.Header().Set("WWW-Authenticate", `Basic realm="Restricted"`)
 		http.Error(w, "missing `Authorization` request header", http.StatusUnauthorized)
 		return true
@@ -110,6 +117,12 @@ func requestHandler(w http.ResponseWriter, r *http.Request) bool {
 		}
 		return true
 	}
+
+	processUserRequest(w, r, ui)
+	return true
+}
+
+func processUserRequest(w http.ResponseWriter, r *http.Request, ui *UserInfo) {
 	ui.requests.Inc()
 
 	// Limit the concurrency of requests to backends
@@ -119,18 +132,17 @@ func requestHandler(w http.ResponseWriter, r *http.Request) bool {
 		if err := ui.beginConcurrencyLimit(); err != nil {
 			handleConcurrencyLimitError(w, r, err)
 			<-concurrencyLimitCh
-			return true
+			return
 		}
 	default:
 		concurrentRequestsLimitReached.Inc()
 		err := fmt.Errorf("cannot serve more than -maxConcurrentRequests=%d concurrent requests", cap(concurrencyLimitCh))
 		handleConcurrencyLimitError(w, r, err)
-		return true
+		return
 	}
 	processRequest(w, r, ui)
 	ui.endConcurrencyLimit()
 	<-concurrencyLimitCh
-	return true
 }
 
 func processRequest(w http.ResponseWriter, r *http.Request, ui *UserInfo) {

docs/vmauth.md

@@ -66,6 +66,10 @@ The following [metrics](#monitoring) related to concurrency limits are exposed b
 - `vmauth_user_concurrent_requests_current{username="..."}` - the current number of concurrent requests for the given `username`.
 - `vmauth_user_concurrent_requests_limit_reached_total{username="foo"}` - the number of requests rejected with `429 Too Many Requests` error
   because of the concurrency limit has been reached for the given `username`.
+- `vmauth_unauthorized_user_concurrent_requests_capacity` - the limit on the number of concurrent requests for unauthorized users (if `unauthorized_user` section is used).
+- `vmauth_unauthorized_user_concurrent_requests_current` - the current number of concurrent requests for unauthorized users (if `unauthorized_user` section is used).
+- `vmauth_unauthorized_user_concurrent_requests_limit_reached_total` - the number of requests rejected with `429 Too Many Requests` error
+  because of the concurrency limit has been reached for unauthorized users (if `unauthorized_user` section is used).
 
 
 ## Auth config
@@ -156,6 +160,18 @@ users:
     url_prefix: "http://vminsert:8480/insert/42/prometheus"
     headers:
     - "X-Scope-OrgID: abc"
+
+# This requests will be executed for requests without Authorization header.
+# For instance, http://vmauth:8427/api/v1/query will be proxied to http://vmselect1:8481/select/0/prometheus/api/v1/query
+unauthorized_user:
+  url_map:
+    - src_paths:
+        - /health
+        - /api/v1/query/
+        - /api/v1/query_range
+      url_prefix:
+        - http://vmselect1:8481/select/0/prometheus
+        - http://vmselect2:8481/select/0/prometheus
 ```
 
 The config may contain `%{ENV_VAR}` placeholders, which are substituted by the corresponding `ENV_VAR` environment variable values.
@@ -198,6 +214,8 @@ users:
   # other config options here
 ```
 
+For unauthorized users `vmauth` exports `vmauth_unauthorized_user_requests_total` metric without label (if `unauthorized_user` section of config is used).
+
 ## How to build from sources
 
 It is recommended using [binary releases](https://github.com/VictoriaMetrics/VictoriaMetrics/releases) - `vmauth` is located in `vmutils-*` archives there.