add remote host

cmd/otel-agent/subcommands/run/command.go

@@ -15,6 +15,7 @@ import (
 	"github.com/DataDog/datadog-agent/comp/api/authtoken/fetchonlyimpl"
 	coreconfig "github.com/DataDog/datadog-agent/comp/core/config"
 	"github.com/DataDog/datadog-agent/comp/core/hostname/hostnameinterface"
+	"github.com/DataDog/datadog-agent/comp/core/hostname/remotehostnameimpl"
 	corelog "github.com/DataDog/datadog-agent/comp/core/log"
 	corelogimpl "github.com/DataDog/datadog-agent/comp/core/log/logimpl"
 	"github.com/DataDog/datadog-agent/comp/core/log/tracelogimpl"
@@ -44,7 +45,6 @@ import (
 	traceconfig "github.com/DataDog/datadog-agent/comp/trace/config"
 	pkgconfigenv "github.com/DataDog/datadog-agent/pkg/config/env"
 	pkgconfigsetup "github.com/DataDog/datadog-agent/pkg/config/setup"
-	"github.com/DataDog/datadog-agent/pkg/security/utils"
 	"github.com/DataDog/datadog-agent/pkg/serializer"
 	"github.com/DataDog/datadog-agent/pkg/trace/telemetry"
 	"github.com/DataDog/datadog-agent/pkg/util/fxutil"
@@ -87,42 +87,7 @@ func (o *orchestratorinterfaceimpl) Reset() {
 	o.f = nil
 }
 
-// TODO create a alternative implementation for hostname.Component that uses the remote host
-// The logic is used by other agents, and so having it exposed as Component would be useful
-type remotehostimpl struct {
-	hostname string
-}
-
-func (r *remotehostimpl) Get(ctx context.Context) (string, error) {
-	if r.hostname != "" {
-		return r.hostname, nil
-	}
-	hostname, err := utils.GetHostnameWithContextAndFallback(ctx)
-	if err != nil {
-		return "", err
-	}
-	r.hostname = hostname
-	return hostname, nil
-}
-
-func (r *remotehostimpl) GetSafe(ctx context.Context) string {
-	h, _ := r.Get(ctx)
-	return h
-}
-
-func (r *remotehostimpl) GetWithProvider(ctx context.Context) (hostnameinterface.Data, error) {
-	h, err := r.Get(ctx)
-	if err != nil {
-		return hostnameinterface.Data{}, err
-	}
-	return hostnameinterface.Data{
-		Hostname: h,
-		Provider: "remote",
-	}, nil
-}
-
 func runOTelAgentCommand(ctx context.Context, params *subcommands.GlobalParams, opts ...fx.Option) error {
-	rh := &remotehostimpl{}
 	err := fxutil.Run(
 		forwarder.Bundle(),
 		tracelogimpl.Module(), // cannot have corelogimpl and tracelogimpl at the same time
@@ -151,13 +116,10 @@ func runOTelAgentCommand(ctx context.Context, params *subcommands.GlobalParams,
 		fx.Provide(func() []string {
 			return append(params.ConfPaths, params.Sets...)
 		}),
-		fx.Provide(func() (serializerexporter.SourceProviderFunc, error) {
-			return rh.Get, nil
-		}),
-		fx.Provide(func() hostnameinterface.Component {
-			return rh
+		fx.Provide(func(h hostnameinterface.Component) (serializerexporter.SourceProviderFunc, error) {
+			return h.Get, nil
 		}),
-
+		fx.Provide(remotehostnameimpl.Module()),
 		fx.Supply(optional.NewNoneOption[secrets.Component]()),
 
 		fx.Provide(func(c coreconfig.Component) corelogimpl.Params {

comp/core/hostname/remotehostnameimpl/hostname.go

@@ -1,3 +1,8 @@
+// Unless explicitly stated otherwise all files in this repository are licensed
+// under the Apache License Version 2.0.
+// This product includes software developed at Datadog (https://www.datadoghq.com/).
+// Copyright 2023-present Datadog, Inc.
+
 // Package remotehostnameimpl provides a function to get the hostname from core agent.
 package remotehostnameimpl
 
@@ -9,30 +14,59 @@ import (
 
 	"github.com/DataDog/datadog-agent/pkg/config"
 	pbgo "github.com/DataDog/datadog-agent/pkg/proto/pbgo/core"
+	"github.com/DataDog/datadog-agent/pkg/util/fxutil"
 	"github.com/DataDog/datadog-agent/pkg/util/grpc"
 	"github.com/DataDog/datadog-agent/pkg/util/hostname"
 	"github.com/DataDog/datadog-agent/pkg/util/log"
+
+	"github.com/DataDog/datadog-agent/comp/core/hostname/hostnameinterface"
+	cache "github.com/patrickmn/go-cache"
+	"go.uber.org/fx"
 )
 
 const (
+	defaultExpire = 15 * time.Minute
+	defaultPurge  = 30 * time.Second
+	// AgentCachePrefix is the common root to use to prefix all the cache
+	// keys for any value regarding the Agent
+	AgentCachePrefix = "agent"
+
+	// encapsulate the cache module for easy refactoring
+
+	// NoExpiration maps to go-cache corresponding value
+	NoExpiration = cache.NoExpiration
 	// maxAttempts is the maximum number of times we try to get the hostname
 	// from the core-agent before bailing out.
 	maxAttempts = 6
 )
 
+// Module defines the fx options for this component.
+func Module() fxutil.Module {
+	return fxutil.Component(
+		fx.Provide(newRemoteHostImpl))
+}
+
+var cachKey = "hostname"
+
 type remotehostimpl struct {
-	hostname string
+	cache *cache.Cache
+}
+
+func newRemoteHostImpl() hostnameinterface.Component {
+	return &remotehostimpl{
+		cache: cache.New(defaultExpire, defaultPurge),
+	}
 }
 
 func (r *remotehostimpl) Get(ctx context.Context) (string, error) {
-	if r.hostname != "" {
-		return r.hostname, nil
+	if hostname, found := r.cache.Get(cachKey); found {
+		return hostname.(string), nil
 	}
-	hostname, err := utils.GetHostnameWithContextAndFallback(ctx)
+	hostname, err := getHostnameWithContextAndFallback(ctx)
 	if err != nil {
 		return "", err
 	}
-	r.hostname = hostname
+	r.cache.Set(cachKey, hostname, NoExpiration)
 	return hostname, nil
 }