build: Append commit hash to the main LND context

It can be disabled via the new `logging.no-commit-hash` config option.

build/config.go

@@ -25,8 +25,9 @@ const (
 //
 //nolint:ll
 type LogConfig struct {
-	Console *consoleLoggerCfg `group:"console" namespace:"console" description:"The logger writing to stdout and stderr."`
-	File    *FileLoggerConfig `group:"file" namespace:"file" description:"The logger writing to LND's standard log file."`
+	Console      *consoleLoggerCfg `group:"console" namespace:"console" description:"The logger writing to stdout and stderr."`
+	File         *FileLoggerConfig `group:"file" namespace:"file" description:"The logger writing to LND's standard log file."`
+	NoCommitHash bool              `long:"no-commit-hash" description:"If set, the commit-hash of the current build will not be included in log lines by default."`
 }
 
 // Validate validates the LogConfig struct values.

build/version.go

@@ -6,9 +6,13 @@
 package build
 
 import (
+	"context"
+	"encoding/hex"
 	"fmt"
 	"runtime/debug"
 	"strings"
+
+	"github.com/btcsuite/btclog/v2"
 )
 
 var (
@@ -101,3 +105,28 @@ func Tags() []string {
 
 	return strings.Split(RawTags, ",")
 }
+
+// WithBuildInfo derives a child context with the build information attached as
+// attributes. At the moment, this only includes the current build's commit
+// hash.
+func WithBuildInfo(ctx context.Context, cfg *LogConfig) (context.Context,
+	error) {
+
+	if cfg.NoCommitHash {
+		return ctx, nil
+	}
+
+	// Convert the commit hash to a byte slice.
+	commitHash, err := hex.DecodeString(CommitHash)
+	if err != nil {
+		return nil, fmt.Errorf("unable to decode commit hash: %w", err)
+	}
+
+	// Include the first 3 bytes of the commit hash in the context as an
+	// slog attribute.
+	if len(commitHash) > 3 {
+		commitHash = commitHash[:3]
+	}
+
+	return btclog.WithCtx(ctx, btclog.Hex("rev", commitHash)), nil
+}