Print generated resource attributes for internal logs (#13111)

#### Link to tracking issue
Fixes #13110

#### Testing
- Improved the unit tests.

Signed-off-by: Israel Blancas <[email protected]>

Author: iblancasa

.chloggen/13110.yaml

@@ -0,0 +1,27 @@
+# Use this changelog template to create an entry for release notes.
+
+# One of 'breaking', 'deprecation', 'new_component', 'enhancement', 'bug_fix'
+change_type: bug_fix
+
+# The name of the component, or a single word describing the area of concern, (e.g. otlpreceiver)
+component: telemetry
+
+# A brief description of the change.  Surround your text with quotes ("") if it needs to start with a backtick (`).
+note: Add generated resource attributes to the printed log messages.
+
+# One or more tracking issues or pull requests related to the change
+issues: [13110]
+
+# (Optional) One or more lines of additional information to render under the primary note.
+# These lines will be padded with 2 spaces and then inserted directly into the document.
+# Use pipe (|) for multiline entries.
+subtext: |
+  If service.name, service.version, or service.instance.id are not specified in the config, they will be generated automatically.
+  This change ensures that these attributes are also included in the printed log messages.
+
+# Optional: The change log or logs in which this entry should be included.
+# e.g. '[user]' or '[user, api]'
+# Include 'user' if the change is relevant to end users.
+# Include 'api' if there is a change to a library API.
+# Default: '[user]'
+change_logs: []

service/service.go

@@ -181,6 +181,7 @@ func New(ctx context.Context, set Settings, cfg Config) (*Service, error) {
 		BuildInfo:         set.BuildInfo,
 		ZapOptions:        set.LoggingOptions,
 		SDK:               &sdk,
+		Resource:          res,
 	}
 
 	logger, lp, err := telFactory.CreateLogger(ctx, telset, &cfg.Telemetry)

service/telemetry/factory.go

@@ -10,6 +10,7 @@ import (
 	config "go.opentelemetry.io/contrib/otelconf/v0.3.0"
 	"go.opentelemetry.io/otel/log"
 	"go.opentelemetry.io/otel/metric"
+	"go.opentelemetry.io/otel/sdk/resource"
 	"go.opentelemetry.io/otel/trace"
 	"go.uber.org/zap"
 	"go.uber.org/zap/zapcore"
@@ -32,6 +33,7 @@ type Settings struct {
 	AsyncErrorChannel chan error
 	ZapOptions        []zap.Option
 	SDK               *config.SDK
+	Resource          *resource.Resource
 }
 
 // Factory is factory interface for telemetry.

service/telemetry/logger.go

@@ -39,21 +39,24 @@ func newLogger(set Settings, cfg Config) (*zap.Logger, log.LoggerProvider, error
 		return nil, nil, err
 	}
 
-	// The attributes in cfg.Resource are added as resource attributes for logs exported through the LoggerProvider instantiated below.
-	// To make sure they are also exposed in logs written to stdout, we add them as fields to the Zap core created above using WrapCore.
-	// We do NOT add them to the logger using With, because that would apply to all logs, even ones exported through the core that wraps
-	// the LoggerProvider, meaning that the attributes would be exported twice.
-	logger = logger.WithOptions(zap.WrapCore(func(c zapcore.Core) zapcore.Core {
-		var fields []zap.Field
-		for k, v := range cfg.Resource {
-			if v != nil {
-				f := zap.Stringp(k, v)
-				fields = append(fields, f)
+	// The attributes in set.Resource.Attributes(), which are generated in service.go, are added
+	// as resource attributes for logs exported through the LoggerProvider instantiated below.
+	// To make sure they are also exposed in logs written to stdout, we add them as fields to the
+	// Zap core created above using WrapCore.
+	// We do NOT add them to the logger using With, because that would apply to all logs, even ones
+	// exported through the core that wraps the LoggerProvider, meaning that the attributes would
+	// be exported twice.
+	if set.Resource != nil && len(set.Resource.Attributes()) > 0 {
+		logger = logger.WithOptions(zap.WrapCore(func(c zapcore.Core) zapcore.Core {
+			var fields []zap.Field
+			for _, attr := range set.Resource.Attributes() {
+				fields = append(fields, zap.String(string(attr.Key), attr.Value.Emit()))
 			}
-		}
-		r := zap.Dict("resource", fields...)
-		return c.With([]zapcore.Field{r})
-	}))
+
+			r := zap.Dict("resource", fields...)
+			return c.With([]zapcore.Field{r})
+		}))
+	}
 
 	var lp log.LoggerProvider
 	logger = logger.WithOptions(zap.WrapCore(func(core zapcore.Core) zapcore.Core {

service/telemetry/logger_test.go

@@ -21,7 +21,9 @@ import (
 	"go.uber.org/zap/zapcore"
 	"go.uber.org/zap/zaptest/observer"
 
+	"go.opentelemetry.io/collector/component"
 	"go.opentelemetry.io/collector/pdata/plog/plogotlp"
+	"go.opentelemetry.io/collector/service/internal/resource"
 )
 
 type shutdownable interface {
@@ -126,38 +128,127 @@ func TestNewLogger(t *testing.T) {
 }
 
 func TestNewLoggerWithResource(t *testing.T) {
-	observerCore, observedLogs := observer.New(zap.InfoLevel)
-
-	set := Settings{
-		ZapOptions: []zap.Option{
-			zap.WrapCore(func(core zapcore.Core) zapcore.Core {
-				// Combine original core and observer core to capture everything
-				return zapcore.NewTee(core, observerCore)
-			}),
+	tests := []struct {
+		name           string
+		buildInfo      component.BuildInfo
+		resourceConfig map[string]*string
+		wantFields     map[string]string
+	}{
+		{
+			name: "auto-populated fields only",
+			buildInfo: component.BuildInfo{
+				Command: "mycommand",
+				Version: "1.0.0",
+			},
+			resourceConfig: map[string]*string{},
+			wantFields: map[string]string{
+				string(semconv.ServiceNameKey):       "mycommand",
+				string(semconv.ServiceVersionKey):    "1.0.0",
+				string(semconv.ServiceInstanceIDKey): "",
+			},
 		},
-	}
-
-	cfg := Config{
-		Logs: LogsConfig{
-			Level:    zapcore.InfoLevel,
-			Encoding: "json",
+		{
+			name: "override service.name",
+			buildInfo: component.BuildInfo{
+				Command: "mycommand",
+				Version: "1.0.0",
+			},
+			resourceConfig: map[string]*string{
+				string(semconv.ServiceNameKey): ptr("custom-service"),
+			},
+			wantFields: map[string]string{
+				string(semconv.ServiceNameKey):       "custom-service",
+				string(semconv.ServiceVersionKey):    "1.0.0",
+				string(semconv.ServiceInstanceIDKey): "",
+			},
 		},
-		Resource: map[string]*string{
-			"myfield": ptr("myvalue"),
+		{
+			name: "override service.version",
+			buildInfo: component.BuildInfo{
+				Command: "mycommand",
+				Version: "1.0.0",
+			},
+			resourceConfig: map[string]*string{
+				string(semconv.ServiceVersionKey): ptr("2.0.0"),
+			},
+			wantFields: map[string]string{
+				string(semconv.ServiceNameKey):       "mycommand",
+				string(semconv.ServiceVersionKey):    "2.0.0",
+				string(semconv.ServiceInstanceIDKey): "",
+			},
+		},
+		{
+			name: "custom field with auto-populated",
+			buildInfo: component.BuildInfo{
+				Command: "mycommand",
+				Version: "1.0.0",
+			},
+			resourceConfig: map[string]*string{
+				"custom.field": ptr("custom-value"),
+			},
+			wantFields: map[string]string{
+				string(semconv.ServiceNameKey):       "mycommand",
+				string(semconv.ServiceVersionKey):    "1.0.0",
+				string(semconv.ServiceInstanceIDKey): "", // Just check presence
+				"custom.field":                       "custom-value",
+			},
+		},
+		{
+			name:           "resource with no attributes",
+			buildInfo:      component.BuildInfo{},
+			resourceConfig: nil,
+			wantFields:     nil,
 		},
 	}
 
-	mylogger, _, _ := newLogger(set, cfg)
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			observerCore, observedLogs := observer.New(zap.InfoLevel)
 
-	mylogger.Info("Test log message")
-	require.Len(t, observedLogs.All(), 1)
+			set := Settings{
+				ZapOptions: []zap.Option{
+					zap.WrapCore(func(core zapcore.Core) zapcore.Core {
+						return zapcore.NewTee(core, observerCore)
+					}),
+				},
+			}
+			if tt.wantFields != nil {
+				set.Resource = resource.New(tt.buildInfo, tt.resourceConfig)
+			}
 
-	entry := observedLogs.All()[0]
-	assert.Equal(t, "resource", entry.Context[0].Key)
-	dict := entry.Context[0].Interface.(zapcore.ObjectMarshaler)
-	enc := zapcore.NewMapObjectEncoder()
-	require.NoError(t, dict.MarshalLogObject(enc))
-	require.Equal(t, "myvalue", enc.Fields["myfield"])
+			cfg := Config{
+				Logs: LogsConfig{
+					Level:    zapcore.InfoLevel,
+					Encoding: "json",
+				},
+			}
+
+			mylogger, _, _ := newLogger(set, cfg)
+			mylogger.Info("Test log message")
+			require.Len(t, observedLogs.All(), 1)
+
+			entry := observedLogs.All()[0]
+			if tt.wantFields == nil {
+				assert.Empty(t, entry.Context)
+				return
+			}
+
+			assert.Equal(t, "resource", entry.Context[0].Key)
+			dict := entry.Context[0].Interface.(zapcore.ObjectMarshaler)
+			enc := zapcore.NewMapObjectEncoder()
+			require.NoError(t, dict.MarshalLogObject(enc))
+
+			// Verify all expected fields
+			for k, v := range tt.wantFields {
+				if k == string(semconv.ServiceInstanceIDKey) {
+					// For service.instance.id just verify it exists since it's auto-generated
+					assert.Contains(t, enc.Fields, k)
+				} else {
+					assert.Equal(t, v, enc.Fields[k])
+				}
+			}
+		})
+	}
 }
 
 func TestOTLPLogExport(t *testing.T) {