2025-04-01 10:38:02 +09:00

131 lines
3.8 KiB
Go

package client
import (
"context"
"fmt"
"net/http"
"net/url"
"time"
httptransport "github.com/go-openapi/runtime/client"
"github.com/grafana/grafana/pkg/infra/log"
"github.com/grafana/grafana/pkg/infra/tracing"
"github.com/grafana/grafana/pkg/services/ngalert/client"
"github.com/grafana/grafana/pkg/services/ngalert/metrics"
amclient "github.com/prometheus/alertmanager/api/v2/client"
)
const alertmanagerAPIMountPath = "/alertmanager"
const alertmanagerReadyPath = "/-/ready"
type AlertmanagerConfig struct {
TenantID string
Password string
URL *url.URL
Logger log.Logger
}
type Alertmanager struct {
*amclient.AlertmanagerAPI
httpClient client.Requester
url *url.URL
logger log.Logger
}
func NewAlertmanager(cfg *AlertmanagerConfig, metrics *metrics.RemoteAlertmanager, tracer tracing.Tracer) (*Alertmanager, error) {
// First, add the authentication middleware.
c := &http.Client{Transport: &MimirAuthRoundTripper{
TenantID: cfg.TenantID,
Password: cfg.Password,
Next: http.DefaultTransport,
}}
tc := client.NewTimedClient(c, metrics.RequestLatency)
trc := client.NewTracedClient(tc, tracer, "remote.alertmanager.client")
apiEndpoint := *cfg.URL
// Next, make sure you set the right path.
u := apiEndpoint.JoinPath(alertmanagerAPIMountPath, amclient.DefaultBasePath)
// Create an Alertmanager client using the instrumented client as the transport.
r := httptransport.New(u.Host, u.Path, []string{u.Scheme})
r.Transport = trc
return &Alertmanager{
logger: cfg.Logger,
url: cfg.URL,
AlertmanagerAPI: amclient.New(r, nil),
httpClient: tc,
}, nil
}
// GetAuthedClient returns a client.Requester that includes a configured MimirAuthRoundTripper.
// Requests using this client are fully authenticated.
func (am *Alertmanager) GetAuthedClient() client.Requester {
return am.httpClient
}
// IsReadyWithBackoff executes a readiness check against the `/-/ready` Alertmanager endpoint.
// It uses exponential backoff (100ms * 2^attempts) with a 10s timeout.
func (am *Alertmanager) IsReadyWithBackoff(ctx context.Context) error {
ctx, cancel := context.WithTimeout(ctx, 10*time.Second)
defer cancel()
var wait time.Duration
for attempt := 1; ; attempt++ {
select {
case <-ctx.Done():
return fmt.Errorf("readiness check timed out")
case <-time.After(wait):
wait = time.Duration(100<<attempt-1) * time.Millisecond
status, err := am.checkReadiness(ctx)
if err != nil {
am.logger.Debug("Readiness check attempt failed", "attempt", attempt, "err", err)
break
}
if status == http.StatusOK {
return nil
}
if status == http.StatusNotAcceptable {
// Mimir returns a 406 when the Alertmanager for the tenant is not running.
// This is expected if the Grafana Alertmanager configuration is default or not promoted.
// We can still use the endpoints to store and retrieve configuration/state.
am.logger.Debug("Remote Alertmanager not initialized for tenant")
return nil
}
if status >= 400 && status < 500 {
return fmt.Errorf("readiness check failed on attempt %d with non-retriable status code %d", attempt, status)
}
am.logger.Debug("Readiness check failed, status code is not 200", "attempt", attempt, "status", status, "err", err)
}
}
}
func (am *Alertmanager) checkReadiness(ctx context.Context) (int, error) {
req, err := http.NewRequestWithContext(
ctx,
http.MethodGet,
am.url.JoinPath(alertmanagerAPIMountPath, alertmanagerReadyPath).String(),
nil,
)
if err != nil {
return 0, fmt.Errorf("error creating the readiness request: %w", err)
}
res, err := am.httpClient.Do(req)
if err != nil {
return 0, fmt.Errorf("error performing the readiness check: %w", err)
}
defer func() {
if err := res.Body.Close(); err != nil {
am.logger.Warn("Error closing response body", "err", err)
}
}()
return res.StatusCode, nil
}