algod: Write to stdout when config.LogSizeLimit is 0 or -o is passed …

…to algod. (#3903)

cmd/algod/main.go

@@ -50,10 +50,11 @@ var versionCheck = flag.Bool("v", false, "Display and write current build versio
 var branchCheck = flag.Bool("b", false, "Display the git branch behind the build")
 var channelCheck = flag.Bool("c", false, "Display and release channel behind the build")
 var initAndExit = flag.Bool("x", false, "Initialize the ledger and exit")
+var logToStdout = flag.Bool("o", false, "Write to stdout instead of node.log by overriding config.LogSizeLimit to 0")
 var peerOverride = flag.String("p", "", "Override phonebook with peer ip:port (or semicolon separated list: ip:port;ip:port;ip:port...)")
 var listenIP = flag.String("l", "", "Override config.EndpointAddress (REST listening address) with ip:port")
 var sessionGUID = flag.String("s", "", "Telemetry Session GUID to use")
-var telemetryOverride = flag.String("t", "", `Override telemetry setting if supported (Use "true", "false", "0" or "1"`)
+var telemetryOverride = flag.String("t", "", `Override telemetry setting if supported (Use "true", "false", "0" or "1")`)
 var seed = flag.String("seed", "", "input to math/rand.Seed()")
 
 func main() {
@@ -292,6 +293,10 @@ func run() int {
 		}
 	}
 
+	if logToStdout != nil && *logToStdout {
+		cfg.LogSizeLimit = 0
+	}
+
 	err = s.Initialize(cfg, phonebookAddresses, string(genesisText))
 	if err != nil {
 		fmt.Fprintln(os.Stderr, err)

config/localTemplate.go

@@ -115,7 +115,7 @@ type Local struct {
 	// SRV-based phonebook
 	DNSBootstrapID string `version[0]:"<network>.algorand.network"`
 
-	// Log file size limit in bytes
+	// Log file size limit in bytes. When set to 0 logs will be written to stdout.
 	LogSizeLimit uint64 `version[0]:"1073741824"`
 
 	// text/template for creating log archive filename.

daemon/algod/server.go

@@ -20,6 +20,7 @@ import (
 	"context"
 	"errors"
 	"fmt"
+	"io"
 	"io/ioutil"
 	"net"
 	"net/http"
@@ -82,7 +83,13 @@ func (s *Server) Initialize(cfg config.Local, phonebookAddresses []string, genes
 			maxLogAge = 0
 		}
 	}
-	logWriter := logging.MakeCyclicFileWriter(liveLog, archive, cfg.LogSizeLimit, maxLogAge)
+
+	var logWriter io.Writer
+	if cfg.LogSizeLimit > 0 {
+		logWriter = logging.MakeCyclicFileWriter(liveLog, archive, cfg.LogSizeLimit, maxLogAge)
+	} else {
+		logWriter = os.Stdout
+	}
 	s.log.SetOutput(logWriter)
 	s.log.SetJSONFormatter()
 	s.log.SetLevel(logging.Level(cfg.BaseLoggerDebugLevel))