ruler: Support OAuth2 and proxies in Alertmanager client (#9945)

* Support for proxies

* Flesh out oauth config

* Tests for proxy_url

* Tests for OAuth2 config options

* Reject multiple auth schemes at the same time

* Generate docs

* Make reference-help

* Fix descriptions

* Make reference-help

* changelog

* Add comma and regenerate

* Migrate to StringSliceCSV as it seems to be the standard and StringSlice seems incomplete

* Remake docs and reference help

CHANGELOG.md

@@ -69,6 +69,7 @@
 * [ENHANCEMENT] Distributor: Initialize ha_tracker cache before ha_tracker and distributor reach running state and begin serving writes. #9826 #9976
 * [ENHANCEMENT] Ingester: `-ingest-storage.kafka.max-buffered-bytes` to limit the memory for buffered records when using concurrent fetching. #9892
 * [ENHANCEMENT] Querier: improve performance and memory consumption of queries that select many series. #9914
+* [ENHANCEMENT] Ruler: Support OAuth2 and proxies in Alertmanager client #9945
 * [BUGFIX] Fix issue where functions such as `rate()` over native histograms could return incorrect values if a float stale marker was present in the selected range. #9508
 * [BUGFIX] Fix issue where negation of native histograms (eg. `-some_native_histogram_series`) did nothing. #9508
 * [BUGFIX] Fix issue where `metric might not be a counter, name does not end in _total/_sum/_count/_bucket` annotation would be emitted even if `rate` or `increase` did not have enough samples to compute a result. #9508

cmd/mimir/config-descriptor.json

@@ -12347,6 +12347,67 @@
               "fieldDefaultValue": "",
               "fieldFlag": "ruler.alertmanager-client.basic-auth-password",
               "fieldType": "string"
+            },
+            {
+              "kind": "block",
+              "name": "oauth2",
+              "required": false,
+              "desc": "",
+              "blockEntries": [
+                {
+                  "kind": "field",
+                  "name": "client_id",
+                  "required": false,
+                  "desc": "OAuth2 client ID. Enables the use of OAuth2 for authenticating with Alertmanager.",
+                  "fieldValue": null,
+                  "fieldDefaultValue": "",
+                  "fieldFlag": "ruler.alertmanager-client.oauth.client_id",
+                  "fieldType": "string"
+                },
+                {
+                  "kind": "field",
+                  "name": "client_secret",
+                  "required": false,
+                  "desc": "OAuth2 client secret.",
+                  "fieldValue": null,
+                  "fieldDefaultValue": "",
+                  "fieldFlag": "ruler.alertmanager-client.oauth.client_secret",
+                  "fieldType": "string"
+                },
+                {
+                  "kind": "field",
+                  "name": "token_url",
+                  "required": false,
+                  "desc": "Endpoint used to fetch access token.",
+                  "fieldValue": null,
+                  "fieldDefaultValue": "",
+                  "fieldFlag": "ruler.alertmanager-client.oauth.token_url",
+                  "fieldType": "string"
+                },
+                {
+                  "kind": "field",
+                  "name": "scopes",
+                  "required": false,
+                  "desc": "Optional scopes to include with the token request.",
+                  "fieldValue": null,
+                  "fieldDefaultValue": "",
+                  "fieldFlag": "ruler.alertmanager-client.oauth.scopes",
+                  "fieldType": "string"
+                }
+              ],
+              "fieldValue": null,
+              "fieldDefaultValue": null
+            },
+            {
+              "kind": "field",
+              "name": "proxy_url",
+              "required": false,
+              "desc": "Optional HTTP, HTTPS via CONNECT, or SOCKS5 proxy URL to route requests through. Applies to all requests, including auxiliary traffic, such as OAuth token requests.",
+              "fieldValue": null,
+              "fieldDefaultValue": "",
+              "fieldFlag": "ruler.alertmanager-client.proxy-url",
+              "fieldType": "string",
+              "fieldCategory": "advanced"
             }
           ],
           "fieldValue": null,

cmd/mimir/help-all.txt.tmpl

@@ -2821,6 +2821,16 @@ Usage of ./cmd/mimir/mimir:
     	HTTP Basic authentication password. It overrides the password set in the URL (if any).
   -ruler.alertmanager-client.basic-auth-username string
     	HTTP Basic authentication username. It overrides the username set in the URL (if any).
+  -ruler.alertmanager-client.oauth.client_id string
+    	OAuth2 client ID. Enables the use of OAuth2 for authenticating with Alertmanager.
+  -ruler.alertmanager-client.oauth.client_secret string
+    	OAuth2 client secret.
+  -ruler.alertmanager-client.oauth.scopes comma-separated-list-of-strings
+    	Optional scopes to include with the token request.
+  -ruler.alertmanager-client.oauth.token_url string
+    	Endpoint used to fetch access token.
+  -ruler.alertmanager-client.proxy-url string
+    	Optional HTTP, HTTPS via CONNECT, or SOCKS5 proxy URL to route requests through. Applies to all requests, including auxiliary traffic, such as OAuth token requests.
   -ruler.alertmanager-client.tls-ca-path string
     	Path to the CA certificates to validate server certificate against. If not set, the host's root CA certificates are used.
   -ruler.alertmanager-client.tls-cert-path string

cmd/mimir/help.txt.tmpl

@@ -711,6 +711,14 @@ Usage of ./cmd/mimir/mimir:
     	HTTP Basic authentication password. It overrides the password set in the URL (if any).
   -ruler.alertmanager-client.basic-auth-username string
     	HTTP Basic authentication username. It overrides the username set in the URL (if any).
+  -ruler.alertmanager-client.oauth.client_id string
+    	OAuth2 client ID. Enables the use of OAuth2 for authenticating with Alertmanager.
+  -ruler.alertmanager-client.oauth.client_secret string
+    	OAuth2 client secret.
+  -ruler.alertmanager-client.oauth.scopes comma-separated-list-of-strings
+    	Optional scopes to include with the token request.
+  -ruler.alertmanager-client.oauth.token_url string
+    	Endpoint used to fetch access token.
   -ruler.alertmanager-url string
     	Comma-separated list of URL(s) of the Alertmanager(s) to send notifications to. Each URL is treated as a separate group. Multiple Alertmanagers in HA per group can be supported by using DNS service discovery format, comprehensive of the scheme. Basic auth is supported as part of the URL.
   -ruler.enable-api

docs/sources/mimir/configure/configuration-parameters/index.md

@@ -1951,6 +1951,30 @@ alertmanager_client:
   # CLI flag: -ruler.alertmanager-client.basic-auth-password
   [basic_auth_password: <string> | default = ""]
 
+  oauth2:
+    # OAuth2 client ID. Enables the use of OAuth2 for authenticating with
+    # Alertmanager.
+    # CLI flag: -ruler.alertmanager-client.oauth.client_id
+    [client_id: <string> | default = ""]
+
+    # OAuth2 client secret.
+    # CLI flag: -ruler.alertmanager-client.oauth.client_secret
+    [client_secret: <string> | default = ""]
+
+    # Endpoint used to fetch access token.
+    # CLI flag: -ruler.alertmanager-client.oauth.token_url
+    [token_url: <string> | default = ""]
+
+    # Optional scopes to include with the token request.
+    # CLI flag: -ruler.alertmanager-client.oauth.scopes
+    [scopes: <string> | default = ""]
+
+  # (advanced) Optional HTTP, HTTPS via CONNECT, or SOCKS5 proxy URL to route
+  # requests through. Applies to all requests, including auxiliary traffic, such
+  # as OAuth token requests.
+  # CLI flag: -ruler.alertmanager-client.proxy-url
+  [proxy_url: <string> | default = ""]
+
 # (advanced) Max time to tolerate outage for restoring "for" state of alert.
 # CLI flag: -ruler.for-outage-tolerance
 [for_outage_tolerance: <duration> | default = 1h]

pkg/ruler/notifier.go

@@ -18,6 +18,7 @@ import (
 	"github.com/grafana/dskit/cache"
 	"github.com/grafana/dskit/cancellation"
 	"github.com/grafana/dskit/crypto/tls"
+	"github.com/grafana/dskit/flagext"
 	config_util "github.com/prometheus/common/config"
 	"github.com/prometheus/common/model"
 	"github.com/prometheus/prometheus/config"
@@ -27,18 +28,43 @@ import (
 	"github.com/grafana/mimir/pkg/util"
 )
 
-var errRulerNotifierStopped = cancellation.NewErrorf("rulerNotifier stopped")
+var (
+	errRulerNotifierStopped               = cancellation.NewErrorf("rulerNotifier stopped")
+	errRulerSimultaneousBasicAuthAndOAuth = errors.New("cannot use both Basic Auth and OAuth2 simultaneously")
+)
 
 type NotifierConfig struct {
 	TLSEnabled bool             `yaml:"tls_enabled" category:"advanced"`
 	TLS        tls.ClientConfig `yaml:",inline"`
 	BasicAuth  util.BasicAuth   `yaml:",inline"`
+	OAuth2     OAuth2Config     `yaml:"oauth2"`
+	ProxyURL   string           `yaml:"proxy_url" category:"advanced"`
 }
 
 func (cfg *NotifierConfig) RegisterFlags(f *flag.FlagSet) {
 	f.BoolVar(&cfg.TLSEnabled, "ruler.alertmanager-client.tls-enabled", true, "Enable TLS for gRPC client connecting to alertmanager.")
 	cfg.TLS.RegisterFlagsWithPrefix("ruler.alertmanager-client", f)
 	cfg.BasicAuth.RegisterFlagsWithPrefix("ruler.alertmanager-client.", f)
+	cfg.OAuth2.RegisterFlagsWithPrefix("ruler.alertmanager-client.oauth.", f)
+	f.StringVar(&cfg.ProxyURL, "ruler.alertmanager-client.proxy-url", "", "Optional HTTP, HTTPS via CONNECT, or SOCKS5 proxy URL to route requests through. Applies to all requests, including auxiliary traffic, such as OAuth token requests.")
+}
+
+type OAuth2Config struct {
+	ClientID     string                 `yaml:"client_id"`
+	ClientSecret flagext.Secret         `yaml:"client_secret"`
+	TokenURL     string                 `yaml:"token_url"`
+	Scopes       flagext.StringSliceCSV `yaml:"scopes,omitempty"`
+}
+
+func (cfg *OAuth2Config) RegisterFlagsWithPrefix(prefix string, f *flag.FlagSet) {
+	f.StringVar(&cfg.ClientID, prefix+"client_id", "", "OAuth2 client ID. Enables the use of OAuth2 for authenticating with Alertmanager.")
+	f.Var(&cfg.ClientSecret, prefix+"client_secret", "OAuth2 client secret.")
+	f.StringVar(&cfg.TokenURL, prefix+"token_url", "", "Endpoint used to fetch access token.")
+	f.Var(&cfg.Scopes, prefix+"scopes", "Optional scopes to include with the token request.")
+}
+
+func (cfg *OAuth2Config) IsEnabled() bool {
+	return cfg.ClientID != "" || cfg.TokenURL != ""
 }
 
 // rulerNotifier bundles a notifier.Manager together with an associated
@@ -176,6 +202,37 @@ func amConfigWithSD(rulerConfig *Config, url *url.URL, sdConfig discovery.Config
 		}
 	}
 
+	// Whether to use an optional HTTP, HTTP+CONNECT, or SOCKS5 proxy.
+	if rulerConfig.Notifier.ProxyURL != "" {
+		url, err := url.Parse(rulerConfig.Notifier.ProxyURL)
+		if err != nil {
+			return nil, err
+		}
+		amConfig.HTTPClientConfig.ProxyURL = config_util.URL{URL: url}
+	}
+
+	// Whether to use OAuth2 or not.
+	if rulerConfig.Notifier.OAuth2.IsEnabled() {
+		if amConfig.HTTPClientConfig.BasicAuth != nil {
+			return nil, errRulerSimultaneousBasicAuthAndOAuth
+		}
+
+		amConfig.HTTPClientConfig.OAuth2 = &config_util.OAuth2{
+			ClientID:     rulerConfig.Notifier.OAuth2.ClientID,
+			ClientSecret: config_util.Secret(rulerConfig.Notifier.OAuth2.ClientSecret.String()),
+			TokenURL:     rulerConfig.Notifier.OAuth2.TokenURL,
+			Scopes:       rulerConfig.Notifier.OAuth2.Scopes,
+		}
+
+		if rulerConfig.Notifier.ProxyURL != "" {
+			url, err := url.Parse(rulerConfig.Notifier.ProxyURL)
+			if err != nil {
+				return nil, err
+			}
+			amConfig.HTTPClientConfig.OAuth2.ProxyURL = config_util.URL{URL: url}
+		}
+	}
+
 	// Whether to use TLS or not.
 	if rulerConfig.Notifier.TLSEnabled {
 		if rulerConfig.Notifier.TLS.Reader == nil {