cosmos-sdk/server/v2/api/telemetry/server.go

127 lines
3.0 KiB
Go

package telemetry
import (
"context"
"encoding/json"
"fmt"
"net/http"
"strings"
"cosmossdk.io/core/transaction"
"cosmossdk.io/log"
serverv2 "cosmossdk.io/server/v2"
)
var (
_ serverv2.ServerComponent[transaction.Tx] = (*Server[transaction.Tx])(nil)
_ serverv2.HasConfig = (*Server[transaction.Tx])(nil)
)
const ServerName = "telemetry"
type Server[T transaction.Tx] struct {
config *Config
logger log.Logger
server *http.Server
metrics *Metrics
}
// New creates a new telemetry server.
func New[T transaction.Tx]() *Server[T] {
return &Server[T]{}
}
// Name returns the server name.
func (s *Server[T]) Name() string {
return ServerName
}
func (s *Server[T]) Config() any {
if s.config == nil || s.config.Address == "" {
return DefaultConfig()
}
return s.config
}
// Init implements serverv2.ServerComponent.
func (s *Server[T]) Init(appI serverv2.AppI[T], cfg map[string]any, logger log.Logger) error {
serverCfg := s.Config().(*Config)
if len(cfg) > 0 {
if err := serverv2.UnmarshalSubConfig(cfg, s.Name(), &serverCfg); err != nil {
return fmt.Errorf("failed to unmarshal config: %w", err)
}
}
s.config = serverCfg
s.logger = logger.With(log.ModuleKey, s.Name())
metrics, err := NewMetrics(s.config)
if err != nil {
return fmt.Errorf("failed to initialize metrics: %w", err)
}
s.metrics = metrics
return nil
}
func (s *Server[T]) Start(ctx context.Context) error {
if !s.config.Enable {
s.logger.Info(fmt.Sprintf("%s server is disabled via config", s.Name()))
return nil
}
mux := http.NewServeMux()
mux.HandleFunc("/", s.metricsHandler)
// keeping /metrics for backwards compatibility
mux.HandleFunc("/metrics", func(w http.ResponseWriter, r *http.Request) {
http.Redirect(w, r, "/", http.StatusMovedPermanently)
})
s.server = &http.Server{
Addr: s.config.Address,
Handler: mux,
}
s.logger.Info("starting telemetry server...", "address", s.config.Address)
if err := s.server.ListenAndServe(); err != nil && err != http.ErrServerClosed {
return fmt.Errorf("failed to start telemetry server: %w", err)
}
return nil
}
func (s *Server[T]) Stop(ctx context.Context) error {
if !s.config.Enable || s.server == nil {
return nil
}
s.logger.Info("stopping telemetry server...", "address", s.config.Address)
return s.server.Shutdown(ctx)
}
func (s *Server[T]) metricsHandler(w http.ResponseWriter, r *http.Request) {
format := strings.TrimSpace(r.FormValue("format"))
// errorResponse defines the attributes of a JSON error response.
type errorResponse struct {
Code int `json:"code,omitempty"`
Error string `json:"error"`
}
gr, err := s.metrics.Gather(format)
if err != nil {
w.Header().Set("Content-Type", "application/json")
w.WriteHeader(http.StatusBadRequest)
bz, err := json.Marshal(errorResponse{Code: 400, Error: fmt.Sprintf("failed to gather metrics: %s", err)})
if err != nil {
return
}
_, _ = w.Write(bz)
return
}
w.Header().Set("Content-Type", gr.ContentType)
_, _ = w.Write(gr.Metrics)
}