Move introspection server to ecs-agent

To make the Agent Introspection Server available to the Fargate agent,
the introspection server is now implemented in the shared ecs-agent
library. The ECS agent introspection server is refactored to use this
shared implementation.

agent/handlers/introspection_server_setup.go

@@ -16,118 +16,36 @@ package handlers
 
 import (
 	"context"
-	"encoding/json"
 	"net/http"
-	"net/http/pprof"
-	"strconv"
 	"time"
 
 	"github.com/aws/amazon-ecs-agent/agent/config"
 	"github.com/aws/amazon-ecs-agent/agent/engine"
-	handlersutils "github.com/aws/amazon-ecs-agent/agent/handlers/utils"
 	v1 "github.com/aws/amazon-ecs-agent/agent/handlers/v1"
-	logginghandler "github.com/aws/amazon-ecs-agent/ecs-agent/tmds/logging"
+	"github.com/aws/amazon-ecs-agent/ecs-agent/introspection"
+	"github.com/aws/amazon-ecs-agent/ecs-agent/metrics"
 	"github.com/aws/amazon-ecs-agent/ecs-agent/utils/retry"
 	"github.com/cihub/seelog"
 )
 
-type rootResponse struct {
-	AvailableCommands []string
-}
-
-const (
-	// With pprof we need to increase the timeout so that there is enough time to do the profiling. Since the profiling
-	// time window for CPU is configurable in the request, this timeout effectively means the CPU profiling will be
-	// capped to 5 min.
-	writeTimeoutForPprof = time.Minute * 5
-	pprofBasePath        = "/debug/pprof/"
-	pprofCMDLinePath     = pprofBasePath + "cmdline"
-	pprofProfilePath     = pprofBasePath + "profile"
-	pprofSymbolPath      = pprofBasePath + "symbol"
-	pprofTracePath       = pprofBasePath + "trace"
-)
-
-var (
-	// Injection points for testing
-	pprofIndexHandler   = pprof.Index
-	pprofCmdlineHandler = pprof.Cmdline
-	pprofProfileHandler = pprof.Profile
-	pprofSymbolHandler  = pprof.Symbol
-	pprofTraceHandler   = pprof.Trace
-)
-
-func introspectionServerSetup(containerInstanceArn *string, taskEngine handlersutils.DockerStateResolver, cfg *config.Config) *http.Server {
-	paths := []string{v1.AgentMetadataPath, v1.TaskContainerMetadataPath, v1.LicensePath}
-
-	if cfg.EnableRuntimeStats.Enabled() {
-		paths = append(paths, pprofBasePath, pprofCMDLinePath, pprofProfilePath, pprofSymbolPath, pprofTracePath)
-	}
-
-	availableCommands := &rootResponse{paths}
-	// Autogenerated list of the above serverFunctions paths
-	availableCommandResponse, err := json.Marshal(&availableCommands)
-	if err != nil {
-		seelog.Errorf("Error marshaling JSON in introspection server setup: %s", err)
-	}
-
-	defaultHandler := func(w http.ResponseWriter, r *http.Request) {
-		w.Write(availableCommandResponse)
-	}
-
-	serverMux := http.NewServeMux()
-	serverMux.HandleFunc("/", defaultHandler)
-
-	v1HandlersSetup(serverMux, containerInstanceArn, taskEngine, cfg)
-	pprofHandlerSetup(serverMux, cfg)
-
-	// Log all requests and then pass through to serverMux
-	loggingServeMux := http.NewServeMux()
-	loggingServeMux.Handle("/", logginghandler.NewLoggingHandler(serverMux))
-
-	wTimeout := writeTimeout
-	if cfg.EnableRuntimeStats.Enabled() {
-		wTimeout = writeTimeoutForPprof
-	}
-	server := &http.Server{
-		Addr:         ":" + strconv.Itoa(config.AgentIntrospectionPort),
-		Handler:      loggingServeMux,
-		ReadTimeout:  readTimeout,
-		WriteTimeout: wTimeout,
-	}
-
-	return server
-}
-
-// v1HandlersSetup adds all handlers except CredentialsHandler in v1 package to the server mux.
-func v1HandlersSetup(serverMux *http.ServeMux,
-	containerInstanceArn *string,
-	taskEngine handlersutils.DockerStateResolver,
-	cfg *config.Config) {
-	serverMux.HandleFunc(v1.AgentMetadataPath, v1.AgentMetadataHandler(containerInstanceArn, cfg))
-	serverMux.HandleFunc(v1.TaskContainerMetadataPath, v1.TaskContainerMetadataHandler(taskEngine))
-	serverMux.HandleFunc(v1.LicensePath, v1.LicenseHandler)
-}
-
-func pprofHandlerSetup(serverMux *http.ServeMux, cfg *config.Config) {
-	if !cfg.EnableRuntimeStats.Enabled() {
-		return
-	}
-	serverMux.HandleFunc(pprofBasePath, pprofIndexHandler)
-	serverMux.HandleFunc(pprofCMDLinePath, pprofCmdlineHandler)
-	serverMux.HandleFunc(pprofProfilePath, pprofProfileHandler)
-	serverMux.HandleFunc(pprofSymbolPath, pprofSymbolHandler)
-	serverMux.HandleFunc(pprofTracePath, pprofTraceHandler)
-}
-
-// ServeIntrospectionHTTPEndpoint serves information about this agent/containerInstance and tasks
-// running on it. "V1" here indicates the hostname version of this server instead
-// of the handler versions, i.e. "V1" server can include "V1" and "V2" handlers.
+// ServeIntrospectionHTTPEndpoint serves information about this agent/containerInstance and tasks running on it.
 func ServeIntrospectionHTTPEndpoint(ctx context.Context, containerInstanceArn *string, taskEngine engine.TaskEngine, cfg *config.Config) {
 	// Is this the right level to type assert, assuming we'd abstract multiple taskengines here?
 	// Revisit if we ever add another type..
 	dockerTaskEngine := taskEngine.(*engine.DockerTaskEngine)
+	agentState := &v1.AgentStateImpl{
+		ContainerInstanceArn: containerInstanceArn,
+		ClusterName:          cfg.Cluster,
+		TaskEngine:           dockerTaskEngine,
+	}
 
-	server := introspectionServerSetup(containerInstanceArn, dockerTaskEngine, cfg)
+	server, _ := introspection.NewServer(
+		agentState,
+		metrics.NewNopEntryFactory(),
+		introspection.WithReadTimeout(readTimeout),
+		introspection.WithWriteTimeout(writeTimeout),
+		introspection.WithRuntimeStats(cfg.EnableRuntimeStats.Enabled()),
+	)
 
 	go func() {
 		<-ctx.Done()