webhook.go

Documentation: github.com/prometheus/alertmanager/notify/webhook

     1  // Copyright 2019 Prometheus Team
     2  // Licensed under the Apache License, Version 2.0 (the "License");
     3  // you may not use this file except in compliance with the License.
     4  // You may obtain a copy of the License at
     5  //
     6  // http://www.apache.org/licenses/LICENSE-2.0
     7  //
     8  // Unless required by applicable law or agreed to in writing, software
     9  // distributed under the License is distributed on an "AS IS" BASIS,
    10  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    11  // See the License for the specific language governing permissions and
    12  // limitations under the License.
    13  
    14  package webhook
    15  
    16  import (
    17  	"bytes"
    18  	"context"
    19  	"encoding/json"
    20  	"fmt"
    21  	"io"
    22  	"net/http"
    23  
    24  	"github.com/go-kit/log"
    25  	"github.com/go-kit/log/level"
    26  	commoncfg "github.com/prometheus/common/config"
    27  
    28  	"github.com/prometheus/alertmanager/config"
    29  	"github.com/prometheus/alertmanager/notify"
    30  	"github.com/prometheus/alertmanager/template"
    31  	"github.com/prometheus/alertmanager/types"
    32  )
    33  
    34  // Notifier implements a Notifier for generic webhooks.
    35  type Notifier struct {
    36  	conf    *config.WebhookConfig
    37  	tmpl    *template.Template
    38  	logger  log.Logger
    39  	client  *http.Client
    40  	retrier *notify.Retrier
    41  }
    42  
    43  // New returns a new Webhook.
    44  func New(conf *config.WebhookConfig, t *template.Template, l log.Logger, httpOpts ...commoncfg.HTTPClientOption) (*Notifier, error) {
    45  	client, err := commoncfg.NewClientFromConfig(*conf.HTTPConfig, "webhook", httpOpts...)
    46  	if err != nil {
    47  		return nil, err
    48  	}
    49  	return &Notifier{
    50  		conf:   conf,
    51  		tmpl:   t,
    52  		logger: l,
    53  		client: client,
    54  		// Webhooks are assumed to respond with 2xx response codes on a successful
    55  		// request and 5xx response codes are assumed to be recoverable.
    56  		retrier: &notify.Retrier{
    57  			CustomDetailsFunc: func(_ int, body io.Reader) string {
    58  				return errDetails(body, conf.URL.String())
    59  			},
    60  		},
    61  	}, nil
    62  }
    63  
    64  // Message defines the JSON object send to webhook endpoints.
    65  type Message struct {
    66  	*template.Data
    67  
    68  	// The protocol version.
    69  	Version         string `json:"version"`
    70  	GroupKey        string `json:"groupKey"`
    71  	TruncatedAlerts uint64 `json:"truncatedAlerts"`
    72  }
    73  
    74  func truncateAlerts(maxAlerts uint64, alerts []*types.Alert) ([]*types.Alert, uint64) {
    75  	if maxAlerts != 0 && uint64(len(alerts)) > maxAlerts {
    76  		return alerts[:maxAlerts], uint64(len(alerts)) - maxAlerts
    77  	}
    78  
    79  	return alerts, 0
    80  }
    81  
    82  // Notify implements the Notifier interface.
    83  func (n *Notifier) Notify(ctx context.Context, alerts ...*types.Alert) (bool, error) {
    84  	alerts, numTruncated := truncateAlerts(n.conf.MaxAlerts, alerts)
    85  	data := notify.GetTemplateData(ctx, n.tmpl, alerts, n.logger)
    86  
    87  	groupKey, err := notify.ExtractGroupKey(ctx)
    88  	if err != nil {
    89  		level.Error(n.logger).Log("err", err)
    90  	}
    91  
    92  	msg := &Message{
    93  		Version:         "4",
    94  		Data:            data,
    95  		GroupKey:        groupKey.String(),
    96  		TruncatedAlerts: numTruncated,
    97  	}
    98  
    99  	var buf bytes.Buffer
   100  	if err := json.NewEncoder(&buf).Encode(msg); err != nil {
   101  		return false, err
   102  	}
   103  
   104  	resp, err := notify.PostJSON(ctx, n.client, n.conf.URL.String(), &buf)
   105  	if err != nil {
   106  		return true, err
   107  	}
   108  	defer notify.Drain(resp)
   109  
   110  	return n.retrier.Check(resp.StatusCode, resp.Body)
   111  }
   112  
   113  func errDetails(body io.Reader, url string) string {
   114  	if body == nil {
   115  		return url
   116  	}
   117  	bs, err := io.ReadAll(body)
   118  	if err != nil {
   119  		return url
   120  	}
   121  	return fmt.Sprintf("%s: %s", url, string(bs))
   122  }
   123
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