package api
import (
"context"
"errors"
"fmt"
"net/http"
"github.com/prometheus/client_golang/api"
)
const (
epHealthCheck = "/-/healthy"
epReadinessCheck = "/-/ready"
epReload = "/-/reload"
epQuit = "/-/quit"
)
type ManagementAPI interface {
HealthCheck(ctx context.Context) error
ReadinessCheck(ctx context.Context) error
Reload(ctx context.Context) error
Quit(ctx context.Context) error
}
type managementAPI struct {
cli api.Client
}
func NewManagementAPI(cli api.Client) ManagementAPI {
return &managementAPI{cli: cli}
}
// This endpoint always returns 200 and should be used to check Prometheus health.
// GET /-/healthy
// HEAD /-/healthy
func (m *managementAPI) HealthCheck(ctx context.Context) error {
resp, body, err := m.cli.Do(ctx, &http.Request{
URL: m.cli.URL(epHealthCheck, nil),
})
if err != nil {
return fmt.Errorf("health check, err: %w", err)
}
if resp.StatusCode != http.StatusOK {
return errors.New(string(body))
}
return nil
}
// This endpoint returns 200 when Prometheus is ready to serve traffic (i.e. respond to queries).
// GET /-/ready
// HEAD /-/ready
func (m *managementAPI) ReadinessCheck(ctx context.Context) error {
resp, body, err := m.cli.Do(ctx, &http.Request{
URL: m.cli.URL(epReadinessCheck, nil),
})
if err != nil {
return fmt.Errorf("readiness check, err: %w", err)
}
if resp.StatusCode != http.StatusOK {
return errors.New(string(body))
}
return nil
}
// This endpoint triggers a reload of the Prometheus configuration and rule files. It's disabled by default and can be enabled via the --web.enable-lifecycle flag.
// Alternatively, a configuration reload can be triggered by sending a SIGHUP to the Prometheus process.
// PUT /-/reload
// POST /-/reload
func (m *managementAPI) Reload(ctx context.Context) error {
resp, body, err := m.cli.Do(ctx, &http.Request{
Method: http.MethodPut,
URL: m.cli.URL(epReload, nil),
})
if err != nil {
return fmt.Errorf("reload configuration and rule files, err: %w", err)
}
if resp.StatusCode != http.StatusOK {
return errors.New(string(body))
}
return nil
}
// This endpoint triggers a graceful shutdown of Prometheus. It's disabled by default and can be enabled via the --web.enable-lifecycle flag.
// Alternatively, a graceful shutdown can be triggered by sending a SIGTERM to the Prometheus process.
// PUT /-/quit
// POST /-/quit
func (m *managementAPI) Quit(ctx context.Context) error {
resp, body, err := m.cli.Do(ctx, &http.Request{
Method: http.MethodPut,
URL: m.cli.URL(epQuit, nil),
})
if err != nil {
return fmt.Errorf("graceful shutdown, err: %w", err)
}
if resp.StatusCode != http.StatusOK {
return errors.New(string(body))
}
return nil
}
