From f360532eb12c92546ec88672508482c5389dab19 Mon Sep 17 00:00:00 2001
From: Jonathan Harvey-Buschel <j.s.harbus@gmail.com>
Date: Mon, 26 Aug 2024 18:43:42 -0400
Subject: [PATCH] lnd+build: add logcompressor flag

---
 build/log.go    | 26 ++++++++++++++++++++++++++
 config.go       |  8 ++++++++
 sample-lnd.conf |  3 +++
 3 files changed, 37 insertions(+)

diff --git a/build/log.go b/build/log.go
index 21c8b953e..484b48e42 100644
--- a/build/log.go
+++ b/build/log.go
@@ -36,6 +36,32 @@ func (t LogType) String() string {
 	}
 }
 
+// Declare the supported log file compressors as exported consts for easier use
+// from other projects.
+const (
+	// Gzip is the default compressor.
+	Gzip = "gzip"
+
+	// Zstd is a modern compressor that compresses better than Gzip, in less
+	// time.
+	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",
+}
+
+// SuportedLogCompressor returns whether or not logCompressor is a supported
+// compression algorithm for log files.
+func SuportedLogCompressor(logCompressor string) bool {
+	_, ok := logCompressors[logCompressor]
+
+	return ok
+}
+
 // LogWriter is a stub type whose behavior can be changed using the build flags
 // "stdlog" and "nolog". The default behavior is to write to both stdout and the
 // RotatorPipe. Passing "stdlog" will cause it only to write to stdout, and
diff --git a/config.go b/config.go
index 34d84720c..dada30ee0 100644
--- a/config.go
+++ b/config.go
@@ -59,6 +59,7 @@ const (
 	defaultLogLevel           = "info"
 	defaultLogDirname         = "logs"
 	defaultLogFilename        = "lnd.log"
+	defaultLogCompressor      = build.Gzip
 	defaultRPCPort            = 10009
 	defaultRESTPort           = 8080
 	defaultPeerPort           = 9735
@@ -315,6 +316,7 @@ type Config struct {
 	ReadMacPath     string        `long:"readonlymacaroonpath" description:"Path to write the read-only macaroon for lnd's RPC and REST services if it doesn't exist"`
 	InvoiceMacPath  string        `long:"invoicemacaroonpath" description:"Path to the invoice-only macaroon for lnd's RPC and REST services if it doesn't exist"`
 	LogDir          string        `long:"logdir" description:"Directory to log output."`
+	LogCompressor   string        `long:"logcompressor" description:"Compression algorithm to use when rotating logs." choice:"gzip" choice:"zstd"`
 	MaxLogFiles     int           `long:"maxlogfiles" description:"Maximum logfiles to keep (0 for no rotation)"`
 	MaxLogFileSize  int           `long:"maxlogfilesize" description:"Maximum logfile size in MB"`
 	AcceptorTimeout time.Duration `long:"acceptortimeout" description:"Time after which an RPCAcceptor will time out and return false if it hasn't yet received a response"`
@@ -560,6 +562,7 @@ func DefaultConfig() Config {
 		LetsEncryptDir:    defaultLetsEncryptDir,
 		LetsEncryptListen: defaultLetsEncryptListen,
 		LogDir:            defaultLogDir,
+		LogCompressor:     defaultLogCompressor,
 		MaxLogFiles:       defaultMaxLogFiles,
 		MaxLogFileSize:    defaultMaxLogFileSize,
 		AcceptorTimeout:   defaultAcceptorTimeout,
@@ -1446,6 +1449,11 @@ func ValidateConfig(cfg Config, interceptor signal.Interceptor, fileParser,
 		os.Exit(0)
 	}
 
+	if !build.SuportedLogCompressor(cfg.LogCompressor) {
+		return nil, mkErr("invalid log compressor: %v",
+			cfg.LogCompressor)
+	}
+
 	// Initialize logging at the default logging level.
 	SetupLoggers(cfg.LogWriter, interceptor)
 	err = cfg.LogWriter.InitLogRotator(
diff --git a/sample-lnd.conf b/sample-lnd.conf
index c9fb0e4f8..56d66b595 100644
--- a/sample-lnd.conf
+++ b/sample-lnd.conf
@@ -36,6 +36,9 @@
 ; Max log file size in MB before it is rotated.
 ; maxlogfilesize=10
 
+; Compression algorithm to use when rotating logs.
+; logcompressor=gzip
+
 ; Time after which an RPCAcceptor will time out and return false if
 ; it hasn't yet received a response.
 ; acceptortimeout=15s