enable default collector (#1044)

Author: aphralG

Diff for: internal/config/config.go

@@ -16,6 +16,9 @@ import (
 	"slices"
 	"strconv"
 	"strings"
+	"time"
+
+	"github.com/nginx/agent/v3/internal/datasource/file"
 
 	uuidLibrary "github.com/nginx/agent/v3/pkg/id"
 	selfsignedcerts "github.com/nginx/agent/v3/pkg/tls"
@@ -115,6 +118,8 @@ func ResolveConfig() (*Config, error) {
 		Labels:             resolveLabels(),
 	}
 
+	checkCollectorConfiguration(collector, config)
+
 	slog.Debug("Agent config", "config", config)
 	slog.Info("Enabled features", "features", config.Features)
 	slog.Info("Excluded files from being watched for file changes", "exclude_files",
@@ -123,6 +128,60 @@ func ResolveConfig() (*Config, error) {
 	return config, nil
 }
 
+func checkCollectorConfiguration(collector *Collector, config *Config) {
+	if isOTelExporterConfigured(collector) && config.IsGrpcClientConfigured() && config.IsAuthConfigured() &&
+		config.IsTLSConfigured() {
+		slog.Info("No collector configuration found in NGINX Agent config, command server configuration found." +
+			"Using default collector configuration")
+		defaultCollector(collector, config)
+	}
+}
+
+func defaultCollector(collector *Collector, config *Config) {
+	token := config.Command.Auth.Token
+	if config.Command.Auth.TokenPath != "" {
+		slog.Debug("Reading token from file", "path", config.Command.Auth.TokenPath)
+		pathToken, err := file.ReadFromFile(config.Command.Auth.TokenPath)
+		if err != nil {
+			slog.Error("Error adding token to default collector, "+
+				"default collector configuration not started", "error", err)
+
+			return
+		}
+		token = pathToken
+	}
+
+	collector.Receivers.HostMetrics = &HostMetrics{
+		Scrapers: &HostMetricsScrapers{
+			CPU:        &CPUScraper{},
+			Disk:       &DiskScraper{},
+			Filesystem: &FilesystemScraper{},
+			Memory:     &MemoryScraper{},
+			Network:    nil,
+		},
+		CollectionInterval: 1 * time.Minute,
+		InitialDelay:       1 * time.Second,
+	}
+
+	collector.Exporters.OtlpExporters = append(collector.Exporters.OtlpExporters, OtlpExporter{
+		Server:        config.Command.Server,
+		TLS:           config.Command.TLS,
+		Compression:   "",
+		Authenticator: "headers_setter",
+	})
+
+	header := []Header{
+		{
+			Action: "insert",
+			Key:    "authorization",
+			Value:  token,
+		},
+	}
+	collector.Extensions.HeadersSetter = &HeadersSetter{
+		Headers: header,
+	}
+}
+
 func setVersion(version, commit string) {
 	RootCommand.Version = version + "-" + commit
 	viperInstance.SetDefault(VersionKey, version)
@@ -911,3 +970,8 @@ func resolveMapStructure(key string, object any) error {
 
 	return nil
 }
+
+func isOTelExporterConfigured(collector *Collector) bool {
+	return len(collector.Exporters.OtlpExporters) == 0 && collector.Exporters.PrometheusExporter == nil &&
+		collector.Exporters.Debug == nil
+}

Diff for: internal/config/types.go

@@ -344,6 +344,23 @@ func (c *Config) IsDirectoryAllowed(directory string) bool {
 	return isAllowedDir(directory, c.AllowedDirectories)
 }
 
+func (c *Config) IsGrpcClientConfigured() bool {
+	return c.Command != nil &&
+		c.Command.Server != nil &&
+		c.Command.Server.Host != "" &&
+		c.Command.Server.Port != 0 &&
+		c.Command.Server.Type == Grpc
+}
+
+func (c *Config) IsAuthConfigured() bool {
+	return c.Command.Auth != nil &&
+		(c.Command.Auth.Token != "" || c.Command.Auth.TokenPath != "")
+}
+
+func (c *Config) IsTLSConfigured() bool {
+	return c.Command.TLS != nil
+}
+
 func (c *Config) IsFeatureEnabled(feature string) bool {
 	for _, enabledFeature := range c.Features {
 		if enabledFeature == feature {

Diff for: internal/datasource/file/file.go

@@ -0,0 +1,37 @@
+// Copyright (c) F5, Inc.
+//
+// This source code is licensed under the Apache License, Version 2.0 license found in the
+// LICENSE file in the root directory of this source tree.
+
+package file
+
+import (
+	"bytes"
+	"errors"
+	"fmt"
+	"os"
+)
+
+// ReadFromFile reads the contents from a file, trims the white space, trims newlines
+// then returns the contents as a string
+func ReadFromFile(path string) (string, error) {
+	if path == "" {
+		return "", errors.New("failed to read file since file path is empty")
+	}
+
+	var content string
+	contentBytes, err := os.ReadFile(path)
+	if err != nil {
+		return "", fmt.Errorf("unable to read from file: %w", err)
+	}
+
+	contentBytes = bytes.TrimSpace(contentBytes)
+	contentBytes = bytes.TrimRight(contentBytes, "\n")
+	content = string(contentBytes)
+
+	if content == "" {
+		return "", errors.New("failed to read from file, file is empty")
+	}
+
+	return content, nil
+}

Diff for: internal/datasource/file/file_test.go

@@ -0,0 +1,64 @@
+// Copyright (c) F5, Inc.
+//
+// This source code is licensed under the Apache License, Version 2.0 license found in the
+// LICENSE file in the root directory of this source tree.
+
+package file
+
+import (
+	"os"
+	"testing"
+
+	"github.com/nginx/agent/v3/test/helpers"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func Test_RetrieveTokenFromFile(t *testing.T) {
+	dir := t.TempDir()
+	tokenFile := helpers.CreateFileWithErrorCheck(t, dir, "test-tkn")
+	defer helpers.RemoveFileWithErrorCheck(t, tokenFile.Name())
+	tests := []struct {
+		name           string
+		path           string
+		expected       string
+		expectedErrMsg string
+		createToken    bool
+	}{
+		{
+			name:           "Test 1: File exists",
+			createToken:    true,
+			path:           tokenFile.Name(),
+			expected:       "test-tkn",
+			expectedErrMsg: "",
+		},
+		{
+			name:           "Test 2: File does not exist",
+			createToken:    false,
+			path:           "test-tkn",
+			expected:       "",
+			expectedErrMsg: "unable to read from file: open test-tkn: no such file or directory",
+		},
+		{
+			name:           "Test 3: Empty path",
+			createToken:    false,
+			path:           "",
+			expected:       "",
+			expectedErrMsg: "failed to read file since file path is empty",
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			if tt.createToken {
+				writeErr := os.WriteFile(tokenFile.Name(), []byte("  test-tkn\n"), 0o600)
+				require.NoError(t, writeErr)
+			}
+
+			token, err := ReadFromFile(tt.path)
+			if err != nil {
+				assert.Equal(t, tt.expectedErrMsg, err.Error())
+			}
+			assert.Equal(t, tt.expected, token)
+		})
+	}
+}

Diff for: internal/grpc/grpc.go

@@ -6,17 +6,17 @@
 package grpc
 
 import (
-	"bytes"
 	"context"
 	"crypto/tls"
 	"errors"
 	"fmt"
 	"log/slog"
 	"net"
-	"os"
 	"strings"
 	"sync"
 
+	"github.com/nginx/agent/v3/internal/datasource/file"
+
 	"github.com/cenkalti/backoff/v4"
 	grpcRetry "github.com/grpc-ecosystem/go-grpc-middleware/retry"
 
@@ -243,7 +243,8 @@ func addPerRPCCredentials(agentConfig *config.Config, resourceID string, opts []
 	token := agentConfig.Command.Auth.Token
 
 	if agentConfig.Command.Auth.TokenPath != "" {
-		tk, err := retrieveTokenFromFile(agentConfig.Command.Auth.TokenPath)
+		slog.Debug("Reading token from file", "path", agentConfig.Command.Auth.TokenPath)
+		tk, err := file.ReadFromFile(agentConfig.Command.Auth.TokenPath)
 		if err == nil {
 			token = tk
 		} else {
@@ -263,29 +264,6 @@ func addPerRPCCredentials(agentConfig *config.Config, resourceID string, opts []
 	return opts
 }
 
-func retrieveTokenFromFile(path string) (string, error) {
-	if path == "" {
-		return "", errors.New("token file path is empty")
-	}
-
-	slog.Debug("Reading token from file", "path", path)
-	var keyVal string
-	keyBytes, err := os.ReadFile(path)
-	if err != nil {
-		return "", fmt.Errorf("unable to read token from file: %w", err)
-	}
-
-	keyBytes = bytes.TrimSpace(keyBytes)
-	keyBytes = bytes.TrimRight(keyBytes, "\n")
-	keyVal = string(keyBytes)
-
-	if keyVal == "" {
-		return "", errors.New("failed to load token, token file is empty")
-	}
-
-	return keyVal, nil
-}
-
 // Have to create our own UnaryClientInterceptor function since protovalidate only provides a UnaryServerInterceptor
 // https://pkg.go.dev/github.com/grpc-ecosystem/go-grpc-middleware/v2@v2.1.0/interceptors/protovalidate
 func ProtoValidatorUnaryClientInterceptor() (grpc.UnaryClientInterceptor, error) {

Diff for: internal/grpc/grpc_test.go

@@ -8,7 +8,6 @@ package grpc
 import (
 	"context"
 	"fmt"
-	"os"
 	"testing"
 
 	"google.golang.org/grpc/credentials"
@@ -356,66 +355,6 @@ func Test_ValidateGrpcError(t *testing.T) {
 	assert.IsType(t, &backoff.PermanentError{}, result)
 }
 
-// nolint:revive,gocognit
-func Test_retrieveTokenFromFile(t *testing.T) {
-	tests := []struct {
-		name        string
-		path        string
-		want        string
-		wantErrMsg  string
-		createToken bool
-	}{
-		{
-			name:        "Test 1: File exists",
-			createToken: true,
-			path:        "test-tkn",
-			want:        "test-tkn",
-			wantErrMsg:  "",
-		},
-		{
-			name:        "Test 2: File does not exist",
-			createToken: false,
-			path:        "test-tkn",
-			want:        "",
-			wantErrMsg:  "unable to read token from file: open test-tkn: no such file or directory",
-		},
-		{
-			name:        "Test 3: Empty path",
-			createToken: false,
-			path:        "",
-			want:        "",
-			wantErrMsg:  "token file path is empty",
-		},
-	}
-	for _, tt := range tests {
-		t.Run(tt.name, func(t *testing.T) {
-			defer func() {
-				if tt.createToken {
-					err := os.Remove(tt.path)
-					if err != nil {
-						t.Log(err)
-					}
-				}
-			}()
-
-			if tt.createToken {
-				err := os.WriteFile(tt.path, []byte(tt.path), 0o600)
-				if err != nil {
-					t.Fatal(err)
-				}
-			}
-
-			got, err := retrieveTokenFromFile(tt.path)
-			if err != nil {
-				if err.Error() != tt.wantErrMsg {
-					t.Errorf("retrieveTokenFromFile() error = %v, wantErr %v", err, tt.wantErrMsg)
-				}
-			}
-			assert.Equalf(t, tt.want, got, "retrieveTokenFromFile(%v)", tt.path)
-		})
-	}
-}
-
 func Test_getTransportCredentials(t *testing.T) {
 	tests := []struct {
 		want    credentials.TransportCredentials

Diff for: internal/plugin/plugin_manager.go

@@ -39,7 +39,7 @@ func addResourcePlugin(plugins []bus.Plugin, agentConfig *config.Config) []bus.P
 }
 
 func addCommandAndFilePlugins(ctx context.Context, plugins []bus.Plugin, agentConfig *config.Config) []bus.Plugin {
-	if isGrpcClientConfigured(agentConfig) {
+	if agentConfig.IsGrpcClientConfigured() {
 		grpcConnection, err := grpc.NewGrpcConnection(ctx, agentConfig)
 		if err != nil {
 			slog.WarnContext(ctx, "Failed to create gRPC connection", "error", err)
@@ -79,11 +79,3 @@ func addWatcherPlugin(plugins []bus.Plugin, agentConfig *config.Config) []bus.Pl
 
 	return plugins
 }
-
-func isGrpcClientConfigured(agentConfig *config.Config) bool {
-	return agentConfig.Command != nil &&
-		agentConfig.Command.Server != nil &&
-		agentConfig.Command.Server.Host != "" &&
-		agentConfig.Command.Server.Port != 0 &&
-		agentConfig.Command.Server.Type == config.Grpc
-}