Add alertmanager provider

This commit adds the alertmanager provider. The provider adds some
generic labels based on the event which should be enough to configure
appropraite routes within alertmanager.

The alert is annotated with the message by default and optionally by the
summary field given in the event.

Signed-off-by: Alan Hollis <me@alanhollis.com>

api/v1beta1/provider_types.go

@@ -28,7 +28,7 @@ const (
 // ProviderSpec defines the desired state of Provider
 type ProviderSpec struct {
 	// Type of provider
-	// +kubebuilder:validation:Enum=slack;discord;msteams;rocket;generic;github;gitlab;bitbucket;azuredevops;googlechat;webex;sentry;azureeventhub;telegram;lark;matrix;opsgenie;
+	// +kubebuilder:validation:Enum=slack;discord;msteams;rocket;generic;github;gitlab;bitbucket;azuredevops;googlechat;webex;sentry;azureeventhub;telegram;lark;matrix;opsgenie;alertmanager;
 	// +required
 	Type string `json:"type"`
 
@@ -81,6 +81,7 @@ const (
 	LarkProvider          string = "lark"
 	Matrix                string = "matrix"
 	OpsgenieProvider      string = "opsgenie"
+	AlertManagerProvider  string = "alertmanager"
 )
 
 // ProviderStatus defines the observed state of Provider

config/crd/bases/notification.toolkit.fluxcd.io_providers.yaml

@@ -91,6 +91,7 @@ spec:
                 - lark
                 - matrix
                 - opsgenie
+                - alertmanager
                 type: string
               username:
                 description: Bot username for this provider

docs/spec/v1beta1/provider.md

@@ -57,6 +57,7 @@ Notification providers:
 * Azure Event Hub
 * Generic webhook
 * Opsgenie
+* Alertmanager
 
 Git commit status providers:
 
@@ -117,7 +118,7 @@ kubectl create secret generic webhook-url \
 Note that the secret must contain an `address` field.
 
 The provider type can be: `slack`, `msteams`, `rocket`, `discord`, `googlechat`, `webex`, `sentry`,
-`telegram`, `lark`, `matrix`, `azureeventhub` or `generic`.
+`telegram`, `lark`, `matrix`, `azureeventhub`, `opsgenie`, `alertmanager` or `generic`.
 
 When type `generic` is specified, the notification controller will post the
 incoming [event](event.md) in JSON format to the webhook address.
@@ -279,6 +280,26 @@ spec:
 ```
 
 
+### Alertmanager
+
+Sends notifications to alertmanager v2 api, if alert manager has basic authentication configured it is recommended to use
+secretRef and include the username:password in the address string.
+
+```yaml
+apiVersion: notification.toolkit.fluxcd.io/v1beta1
+kind: Provider
+metadata:
+  name: alertmanager
+  namespace: default
+spec:
+  type: alertmanager
+  # webhook address (ignored if secretRef is specified)
+  address: https://....@<alertmanager-url>/api/v2/alerts/"
+```
+
+
+
+
 ### Git commit status
 
 The GitHub, GitLab, Bitbucket, and Azure DevOps provider will write to the
@@ -340,7 +361,6 @@ data:
   token: <username>:<app-password>
 ```
 
-
 Opsgenie uses an api key to authenticate [api key](https://support.atlassian.com/opsgenie/docs/api-key-management/).
 The providers require a secret in the same format, with the api key as the value for the token key:
 

internal/notifier/alertmanager.go

@@ -0,0 +1,90 @@
+/*
+Copyright 2020 The Flux authors
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package notifier
+
+import (
+	"crypto/x509"
+	"fmt"
+	"net/url"
+
+	"github.com/fluxcd/pkg/runtime/events"
+)
+
+type Alertmanager struct {
+	URL      string
+	ProxyURL string
+	CertPool *x509.CertPool
+}
+
+type AlertManagerAlert struct {
+	Status      string            `json:"status"`
+	Labels      map[string]string `json:"labels"`
+	Annotations map[string]string `json:"annotations"`
+}
+
+func NewAlertmanager(hookURL string, proxyURL string, certPool *x509.CertPool) (*Alertmanager, error) {
+	_, err := url.ParseRequestURI(hookURL)
+	if err != nil {
+		return nil, fmt.Errorf("invalid Alertmanager URL %s", hookURL)
+	}
+
+	return &Alertmanager{
+		URL:      hookURL,
+		ProxyURL: proxyURL,
+		CertPool: certPool,
+	}, nil
+}
+
+func (s *Alertmanager) Post(event events.Event) error {
+	// Skip any update events
+	if isCommitStatus(event.Metadata, "update") {
+		return nil
+	}
+
+	annotations := make(map[string]string)
+	annotations["message"] = event.Message
+
+	_, ok := event.Metadata["summary"]
+	if ok {
+		annotations["summary"] = event.Metadata["summary"]
+		delete(event.Metadata, "summary")
+	}
+
+	labels := event.Metadata
+	labels["alertname"] = "FluxNotification"
+	labels["severity"] = event.Severity
+	labels["reason"] = event.Reason
+
+	labels["kind"] = event.InvolvedObject.Kind
+	labels["name"] = event.InvolvedObject.Name
+	labels["namespace"] = event.InvolvedObject.Namespace
+
+	payload := []AlertManagerAlert{
+		{
+			Labels:      labels,
+			Annotations: annotations,
+			Status:      "firing",
+		},
+	}
+
+	err := postMessage(s.URL, s.ProxyURL, s.CertPool, payload)
+
+	if err != nil {
+		return fmt.Errorf("postMessage failed: %w", err)
+	}
+	return nil
+}

internal/notifier/alertmanger_test.go

@@ -0,0 +1,45 @@
+/*
+Copyright 2020 The Flux authors
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package notifier
+
+import (
+	"encoding/json"
+	"io/ioutil"
+	"net/http"
+	"net/http/httptest"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+func TestAlertmanager_Post(t *testing.T) {
+	ts := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		b, err := ioutil.ReadAll(r.Body)
+		require.NoError(t, err)
+		var payload []AlertManagerAlert
+		err = json.Unmarshal(b, &payload)
+		require.NoError(t, err)
+
+	}))
+	defer ts.Close()
+
+	alertmanager, err := NewAlertmanager(ts.URL, "", nil)
+	require.NoError(t, err)
+
+	err = alertmanager.Post(testEvent())
+	require.NoError(t, err)
+}

internal/notifier/factory.go

@@ -85,6 +85,8 @@ func (f Factory) Notifier(provider string) (Interface, error) {
 		n, err = NewMatrix(f.URL, f.Token, f.Channel)
 	case v1beta1.OpsgenieProvider:
 		n, err = NewOpsgenie(f.URL, f.ProxyURL, f.CertPool, f.Token)
+	case v1beta1.AlertManagerProvider:
+		n, err = NewAlertmanager(f.URL, f.ProxyURL, f.CertPool)
 	default:
 		err = fmt.Errorf("provider %s not supported", provider)
 	}

internal/notifier/opsgenie.go

@@ -39,7 +39,6 @@ type OpsgenieAlert struct {
 	Details     map[string]string `json:"details"`
 }
 
-// NewSlack validates the Slack URL and returns a Slack object
 func NewOpsgenie(hookURL string, proxyURL string, certPool *x509.CertPool, token string) (*Opsgenie, error) {
 	_, err := url.ParseRequestURI(hookURL)
 	if err != nil {