fixup! main: add logcompressor flag

config.go

@@ -41,7 +41,7 @@ const (
 	defaultLogLevel              = "info"
 	defaultLogDirname            = "logs"
 	defaultLogFilename           = "btcd.log"
-	defaultLogCompressor         = "gzip"
+	defaultLogCompressor         = Gzip
 	defaultMaxPeers              = 125
 	defaultBanDuration           = time.Hour * 24
 	defaultBanThreshold          = 100
@@ -126,7 +126,7 @@ type config struct {
 	FreeTxRelayLimit     float64       `long:"limitfreerelay" description:"Limit relay of transactions with no transaction fee to the given amount in thousands of bytes per minute"`
 	Listeners            []string      `long:"listen" description:"Add an interface/port to listen for connections (default all interfaces port: 8333, testnet: 18333)"`
 	LogDir               string        `long:"logdir" description:"Directory to log output."`
-	LogCompressor        string        `long:"logcompressor" description:"Compression algorithm to use when rotating logs.  Valid algorithms are: gzip and zstd."`
+	LogCompressor        string        `long:"logcompressor" description:"Compression algorithm to use when rotating logs." choice:"gzip" choice:"zstd"`
 	MaxOrphanTxs         int           `long:"maxorphantx" description:"Max number of orphan transactions to keep in memory"`
 	MaxPeers             int           `long:"maxpeers" description:"Max number of inbound and outbound peers"`
 	MiningAddrs          []string      `long:"miningaddr" description:"Add the specified payment address to the list of addresses to use for generated blocks -- At least one address is required if the generate option is set"`
@@ -665,7 +665,7 @@ func loadConfig() (*config, []string, error) {
 	}
 
 	// Validate that the selected log compression algorithm is supported.
-	if _, ok := logCompressors[cfg.LogCompressor]; !ok {
+	if !supportedCompressor(cfg.LogCompressor) {
 		str := "%s: The specified log compressor [%v] is invalid"
 		err := fmt.Errorf(str, funcName, cfg.LogCompressor)
 		fmt.Fprintln(os.Stderr, err)

log.go

@@ -107,11 +107,23 @@ var subsystemLoggers = map[string]btclog.Logger{
 	"TXMP": txmpLog,
 }
 
+// Declare the supported compressors as exported consts for easier use from
+// other projects.
+const (
+	Gzip = "gzip"
+	Zstd = "zstd"
+)
+
 // logCompressors maps the identifier for each supported compression algorithm
 // to the extension used for the compressed log files.
 var logCompressors = map[string]string{
-	"gzip": "gz",
-	"zstd": "zst",
+	Gzip: "gz",
+	Zstd: "zst",
+}
+
+func supportedCompressor(compressor string) bool {
+	_, ok := logCompressors[compressor]
+	return ok
 }
 
 // initLogRotator initializes the logging rotater to write logs to logFile and
@@ -130,8 +142,12 @@ func initLogRotator(logFile, logCompressor string) {
 		os.Exit(1)
 	}
 
-	// The selected compressor was validated by the caller, so we don't need
-	// to handle an unknown compressor here.
+	// Reject unknown compressors.
+	if !supportedCompressor(cfg.LogCompressor) {
+		fmt.Printf("specified log compressor [%v] is invalid",
+			cfg.LogCompressor)
+	}
+
 	var c rotator.Compressor
 	switch logCompressor {
 	case "gzip":