feat: webhook template

config/config.go

@@ -271,6 +271,9 @@ func resolveFilepaths(baseDir string, cfg *Config) {
 		for _, cfg := range receiver.WebhookConfigs {
 			cfg.HTTPConfig.SetDirectory(baseDir)
 		}
+		for _, cfg := range receiver.WebHookTemplateConfigs {
+			cfg.HTTPConfig.SetDirectory(baseDir)
+		}
 		for _, cfg := range receiver.WechatConfigs {
 			cfg.HTTPConfig.SetDirectory(baseDir)
 		}
@@ -412,6 +415,11 @@ func (c *Config) UnmarshalYAML(unmarshal func(interface{}) error) error {
 				wh.HTTPConfig = c.Global.HTTPConfig
 			}
 		}
+		for _, wh := range rcv.WebHookTemplateConfigs {
+			if wh.HTTPConfig == nil {
+				wh.HTTPConfig = c.Global.HTTPConfig
+			}
+		}
 		for _, ec := range rcv.EmailConfigs {
 			if ec.TLSConfig == nil {
 				ec.TLSConfig = c.Global.SMTPTLSConfig
@@ -1010,22 +1018,23 @@ type Receiver struct {
 	// A unique identifier for this receiver.
 	Name string `yaml:"name" json:"name"`
 
-	DiscordConfigs    []*DiscordConfig    `yaml:"discord_configs,omitempty" json:"discord_configs,omitempty"`
-	EmailConfigs      []*EmailConfig      `yaml:"email_configs,omitempty" json:"email_configs,omitempty"`
-	PagerdutyConfigs  []*PagerdutyConfig  `yaml:"pagerduty_configs,omitempty" json:"pagerduty_configs,omitempty"`
-	SlackConfigs      []*SlackConfig      `yaml:"slack_configs,omitempty" json:"slack_configs,omitempty"`
-	WebhookConfigs    []*WebhookConfig    `yaml:"webhook_configs,omitempty" json:"webhook_configs,omitempty"`
-	OpsGenieConfigs   []*OpsGenieConfig   `yaml:"opsgenie_configs,omitempty" json:"opsgenie_configs,omitempty"`
-	WechatConfigs     []*WechatConfig     `yaml:"wechat_configs,omitempty" json:"wechat_configs,omitempty"`
-	PushoverConfigs   []*PushoverConfig   `yaml:"pushover_configs,omitempty" json:"pushover_configs,omitempty"`
-	VictorOpsConfigs  []*VictorOpsConfig  `yaml:"victorops_configs,omitempty" json:"victorops_configs,omitempty"`
-	SNSConfigs        []*SNSConfig        `yaml:"sns_configs,omitempty" json:"sns_configs,omitempty"`
-	TelegramConfigs   []*TelegramConfig   `yaml:"telegram_configs,omitempty" json:"telegram_configs,omitempty"`
-	WebexConfigs      []*WebexConfig      `yaml:"webex_configs,omitempty" json:"webex_configs,omitempty"`
-	MSTeamsConfigs    []*MSTeamsConfig    `yaml:"msteams_configs,omitempty" json:"msteams_configs,omitempty"`
-	MSTeamsV2Configs  []*MSTeamsV2Config  `yaml:"msteamsv2_configs,omitempty" json:"msteamsv2_configs,omitempty"`
-	JiraConfigs       []*JiraConfig       `yaml:"jira_configs,omitempty" json:"jira_configs,omitempty"`
-	RocketchatConfigs []*RocketchatConfig `yaml:"rocketchat_configs,omitempty" json:"rocketchat_configs,omitempty"`
+	DiscordConfigs         []*DiscordConfig         `yaml:"discord_configs,omitempty" json:"discord_configs,omitempty"`
+	EmailConfigs           []*EmailConfig           `yaml:"email_configs,omitempty" json:"email_configs,omitempty"`
+	PagerdutyConfigs       []*PagerdutyConfig       `yaml:"pagerduty_configs,omitempty" json:"pagerduty_configs,omitempty"`
+	SlackConfigs           []*SlackConfig           `yaml:"slack_configs,omitempty" json:"slack_configs,omitempty"`
+	WebhookConfigs         []*WebhookConfig         `yaml:"webhook_configs,omitempty" json:"webhook_configs,omitempty"`
+	WebHookTemplateConfigs []*WebhookTemplateConfig `yaml:"webhook_template_configs,omitempty" json:"webhook_template_configs,omitempty"`
+	OpsGenieConfigs        []*OpsGenieConfig        `yaml:"opsgenie_configs,omitempty" json:"opsgenie_configs,omitempty"`
+	WechatConfigs          []*WechatConfig          `yaml:"wechat_configs,omitempty" json:"wechat_configs,omitempty"`
+	PushoverConfigs        []*PushoverConfig        `yaml:"pushover_configs,omitempty" json:"pushover_configs,omitempty"`
+	VictorOpsConfigs       []*VictorOpsConfig       `yaml:"victorops_configs,omitempty" json:"victorops_configs,omitempty"`
+	SNSConfigs             []*SNSConfig             `yaml:"sns_configs,omitempty" json:"sns_configs,omitempty"`
+	TelegramConfigs        []*TelegramConfig        `yaml:"telegram_configs,omitempty" json:"telegram_configs,omitempty"`
+	WebexConfigs           []*WebexConfig           `yaml:"webex_configs,omitempty" json:"webex_configs,omitempty"`
+	MSTeamsConfigs         []*MSTeamsConfig         `yaml:"msteams_configs,omitempty" json:"msteams_configs,omitempty"`
+	MSTeamsV2Configs       []*MSTeamsV2Config       `yaml:"msteamsv2_configs,omitempty" json:"msteamsv2_configs,omitempty"`
+	JiraConfigs            []*JiraConfig            `yaml:"jira_configs,omitempty" json:"jira_configs,omitempty"`
+	RocketchatConfigs      []*RocketchatConfig      `yaml:"rocketchat_configs,omitempty" json:"rocketchat_configs,omitempty"`
 }
 
 // UnmarshalYAML implements the yaml.Unmarshaler interface for Receiver.

config/notifiers.go

@@ -35,6 +35,13 @@ var (
 		},
 	}
 
+	// DefaultWebhookTemplateConfig defines default values for Webhook template configurations.
+	DefaultWebhookTemplateConfig = WebhookTemplateConfig{
+		NotifierConfig: NotifierConfig{
+			VSendResolved: true,
+		},
+	}
+
 	// DefaultWebexConfig defines default values for Webex configurations.
 	DefaultWebexConfig = WebexConfig{
 		NotifierConfig: NotifierConfig{
@@ -557,6 +564,39 @@ func (c *WebhookConfig) UnmarshalYAML(unmarshal func(interface{}) error) error {
 	return nil
 }
 
+// WebhookTemplateConfig configures notifications via a generic webhook.
+type WebhookTemplateConfig struct {
+	NotifierConfig `yaml:",inline" json:",inline"`
+
+	HTTPConfig *commoncfg.HTTPClientConfig `yaml:"http_config,omitempty" json:"http_config,omitempty"`
+
+	// URL to send POST request to.
+	URL     *SecretURL `yaml:"url" json:"url"`
+	URLFile string     `yaml:"url_file" json:"url_file"`
+
+	Template string `yaml:"template,omitempty" json:"template,omitempty"`
+
+	// Timeout is the maximum time allowed to invoke the webhook. Setting this to 0
+	// does not impose a timeout.
+	Timeout time.Duration `yaml:"timeout" json:"timeout"`
+}
+
+// UnmarshalYAML implements the yaml.Unmarshaler interface.
+func (c *WebhookTemplateConfig) UnmarshalYAML(unmarshal func(interface{}) error) error {
+	*c = DefaultWebhookTemplateConfig
+	type plain WebhookTemplateConfig
+	if err := unmarshal((*plain)(c)); err != nil {
+		return err
+	}
+	if c.URL == nil && c.URLFile == "" {
+		return errors.New("one of url or url_file must be configured")
+	}
+	if c.URL != nil && c.URLFile != "" {
+		return errors.New("at most one of url & url_file must be configured")
+	}
+	return nil
+}
+
 // WechatConfig configures notifications via Wechat.
 type WechatConfig struct {
 	NotifierConfig `yaml:",inline" json:",inline"`

config/receiver/receiver.go

@@ -36,6 +36,7 @@ import (
 	"github.com/prometheus/alertmanager/notify/victorops"
 	"github.com/prometheus/alertmanager/notify/webex"
 	"github.com/prometheus/alertmanager/notify/webhook"
+	"github.com/prometheus/alertmanager/notify/webhook_template"
 	"github.com/prometheus/alertmanager/notify/wechat"
 	"github.com/prometheus/alertmanager/template"
 	"github.com/prometheus/alertmanager/types"
@@ -64,6 +65,9 @@ func BuildReceiverIntegrations(nc config.Receiver, tmpl *template.Template, logg
 	for i, c := range nc.WebhookConfigs {
 		add("webhook", i, c, func(l *slog.Logger) (notify.Notifier, error) { return webhook.New(c, tmpl, l, httpOpts...) })
 	}
+	for i, c := range nc.WebHookTemplateConfigs {
+		add("webhook_template", i, c, func(l *slog.Logger) (notify.Notifier, error) { return webhook_template.New(c, tmpl, l, httpOpts...) })
+	}
 	for i, c := range nc.EmailConfigs {
 		add("email", i, c, func(l *slog.Logger) (notify.Notifier, error) { return email.New(c, tmpl, l), nil })
 	}

config/receiver/receiver_test.go

@@ -68,21 +68,58 @@ func TestBuildReceiverIntegrations(t *testing.T) {
 			},
 			err: true,
 		},
+		{
+			receiver: config.Receiver{
+				Name: "foo",
+				WebHookTemplateConfigs: []*config.WebhookTemplateConfig{
+					{
+						HTTPConfig: &commoncfg.HTTPClientConfig{},
+					},
+					{
+						HTTPConfig: &commoncfg.HTTPClientConfig{},
+						NotifierConfig: config.NotifierConfig{
+							VSendResolved: true,
+						},
+					},
+				},
+			},
+			exp: []notify.Integration{
+				notify.NewIntegration(nil, sendResolved(false), "webhook_template", 0, "foo"),
+				notify.NewIntegration(nil, sendResolved(true), "webhook_template", 1, "foo"),
+			},
+		},
+		{
+			receiver: config.Receiver{
+				Name: "foo",
+				WebHookTemplateConfigs: []*config.WebhookTemplateConfig{
+					{
+						HTTPConfig: &commoncfg.HTTPClientConfig{
+							TLSConfig: commoncfg.TLSConfig{
+								CAFile: "not_existing",
+							},
+						},
+					},
+				},
+			},
+			err: true,
+		},
 	} {
 		tc := tc
-		t.Run("", func(t *testing.T) {
-			integrations, err := BuildReceiverIntegrations(tc.receiver, nil, nil)
-			if tc.err {
-				require.Error(t, err)
-				return
-			}
-			require.NoError(t, err)
-			require.Len(t, integrations, len(tc.exp))
-			for i := range tc.exp {
-				require.Equal(t, tc.exp[i].SendResolved(), integrations[i].SendResolved())
-				require.Equal(t, tc.exp[i].Name(), integrations[i].Name())
-				require.Equal(t, tc.exp[i].Index(), integrations[i].Index())
-			}
-		})
+		t.Run(
+			"", func(t *testing.T) {
+				integrations, err := BuildReceiverIntegrations(tc.receiver, nil, nil)
+				if tc.err {
+					require.Error(t, err)
+					return
+				}
+				require.NoError(t, err)
+				require.Len(t, integrations, len(tc.exp))
+				for i := range tc.exp {
+					require.Equal(t, tc.exp[i].SendResolved(), integrations[i].SendResolved())
+					require.Equal(t, tc.exp[i].Name(), integrations[i].Name())
+					require.Equal(t, tc.exp[i].Index(), integrations[i].Index())
+				}
+			},
+		)
 	}
 }

notify/webhook_template/webhook_template.go

@@ -0,0 +1,112 @@
+// Copyright 2019 Prometheus Team
+// 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 webhook_template
+
+import (
+	"bytes"
+	"context"
+	"encoding/json"
+	"fmt"
+	"log/slog"
+	"net/http"
+	"os"
+	"strings"
+
+	commoncfg "github.com/prometheus/common/config"
+
+	"github.com/prometheus/alertmanager/config"
+	"github.com/prometheus/alertmanager/notify"
+	"github.com/prometheus/alertmanager/template"
+	"github.com/prometheus/alertmanager/types"
+)
+
+// Notifier implements a Notifier for generic webhooks.
+type Notifier struct {
+	conf    *config.WebhookTemplateConfig
+	tmpl    *template.Template
+	logger  *slog.Logger
+	client  *http.Client
+	retrier *notify.Retrier
+}
+
+// New returns a new Webhook.
+func New(conf *config.WebhookTemplateConfig, t *template.Template, l *slog.Logger, httpOpts ...commoncfg.HTTPClientOption) (*Notifier, error) {
+	client, err := commoncfg.NewClientFromConfig(*conf.HTTPConfig, "webhook_template", httpOpts...)
+	if err != nil {
+		return nil, err
+	}
+	return &Notifier{
+		conf:   conf,
+		tmpl:   t,
+		logger: l,
+		client: client,
+		// Webhooks are assumed to respond with 2xx response codes on a successful
+		// request and 5xx response codes are assumed to be recoverable.
+		retrier: &notify.Retrier{},
+	}, nil
+}
+
+// Notify implements the Notifier interface.
+func (n *Notifier) Notify(ctx context.Context, alerts ...*types.Alert) (bool, error) {
+	key, err := notify.ExtractGroupKey(ctx)
+	if err != nil {
+		return false, err
+	}
+	n.logger.Debug("extracted group key", "key", key)
+
+	data := notify.GetTemplateData(ctx, n.tmpl, alerts, n.logger)
+	tmpl := notify.TmplText(n.tmpl, data, &err)
+	if err != nil {
+		return false, err
+	}
+
+	body := tmpl(n.conf.Template)
+
+	var buf bytes.Buffer
+	if err := json.NewEncoder(&buf).Encode(body); err != nil {
+		return false, err
+	}
+
+	var url string
+	if n.conf.URL != nil {
+		url = n.conf.URL.String()
+	} else {
+		content, err := os.ReadFile(n.conf.URLFile)
+		if err != nil {
+			return false, fmt.Errorf("read url_file: %w", err)
+		}
+		url = strings.TrimSpace(string(content))
+	}
+
+	if n.conf.Timeout > 0 {
+		postCtx, cancel := context.WithTimeoutCause(ctx, n.conf.Timeout, fmt.Errorf("configured webhook template timeout reached (%s)", n.conf.Timeout))
+		defer cancel()
+		ctx = postCtx
+	}
+
+	resp, err := notify.PostJSON(ctx, n.client, url, &buf)
+	if err != nil {
+		if ctx.Err() != nil {
+			err = fmt.Errorf("%w: %w", err, context.Cause(ctx))
+		}
+		return true, notify.RedactURL(err)
+	}
+	defer notify.Drain(resp)
+
+	shouldRetry, err := n.retrier.Check(resp.StatusCode, resp.Body)
+	if err != nil {
+		return shouldRetry, notify.NewErrorWithReason(notify.GetFailureReasonFromStatusCode(resp.StatusCode), err)
+	}
+	return shouldRetry, err
+}