alertmanager/notify/webhook/webhook.go

122 lines
3.4 KiB
Go

// 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
import (
"bytes"
"context"
"encoding/json"
"fmt"
"io"
"net/http"
"github.com/go-kit/kit/log"
"github.com/go-kit/kit/log/level"
commoncfg "github.com/prometheus/common/config"
"github.com/prometheus/common/version"
"github.com/prometheus/alertmanager/config"
"github.com/prometheus/alertmanager/notify"
"github.com/prometheus/alertmanager/template"
"github.com/prometheus/alertmanager/types"
)
var userAgentHeader = fmt.Sprintf("Alertmanager/%s", version.Version)
// Notifier implements a Notifier for generic webhooks.
type Notifier struct {
conf *config.WebhookConfig
tmpl *template.Template
logger log.Logger
client *http.Client
retrier *notify.Retrier
}
// New returns a new Webhook.
func New(conf *config.WebhookConfig, t *template.Template, l log.Logger, httpOpts ...commoncfg.HTTPClientOption) (*Notifier, error) {
client, err := commoncfg.NewClientFromConfig(*conf.HTTPConfig, "webhook", append(httpOpts, commoncfg.WithHTTP2Disabled())...)
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{
CustomDetailsFunc: func(int, io.Reader) string {
return conf.URL.String()
},
},
}, nil
}
// Message defines the JSON object send to webhook endpoints.
type Message struct {
*template.Data
// The protocol version.
Version string `json:"version"`
GroupKey string `json:"groupKey"`
TruncatedAlerts uint64 `json:"truncatedAlerts"`
}
func truncateAlerts(maxAlerts uint64, alerts []*types.Alert) ([]*types.Alert, uint64) {
if maxAlerts != 0 && uint64(len(alerts)) > maxAlerts {
return alerts[:maxAlerts], uint64(len(alerts)) - maxAlerts
}
return alerts, 0
}
// Notify implements the Notifier interface.
func (n *Notifier) Notify(ctx context.Context, alerts ...*types.Alert) (bool, error) {
alerts, numTruncated := truncateAlerts(n.conf.MaxAlerts, alerts)
data := notify.GetTemplateData(ctx, n.tmpl, alerts, n.logger)
groupKey, err := notify.ExtractGroupKey(ctx)
if err != nil {
level.Error(n.logger).Log("err", err)
}
msg := &Message{
Version: "4",
Data: data,
GroupKey: groupKey.String(),
TruncatedAlerts: numTruncated,
}
var buf bytes.Buffer
if err := json.NewEncoder(&buf).Encode(msg); err != nil {
return false, err
}
req, err := http.NewRequest("POST", n.conf.URL.String(), &buf)
if err != nil {
return true, err
}
req.Header.Set("Content-Type", "application/json")
req.Header.Set("User-Agent", userAgentHeader)
resp, err := n.client.Do(req.WithContext(ctx))
if err != nil {
return true, err
}
notify.Drain(resp)
return n.retrier.Check(resp.StatusCode, nil)
}