Add a non-optional Json file log for the beacon node as stopgap measure (#1322)

* Add a non-optional Json file log for the beacon node as stopgap measure

* Fix the build with -d:testnet_servers_image

Makefile

@@ -184,6 +184,7 @@ altona: | beacon_node
 	build/beacon_node \
 		--network=altona \
 		--log-level="$(LOG_LEVEL)" \
+		--log-file=nbc_bn_$$(date +"%Y%m%d%H%M%S").log \
 		--data-dir=build/data/shared_altona_$(NODE_ID) \
 		$(GOERLI_TESTNETS_PARAMS) $(NODE_PARAMS)
 

beacon_chain/beacon_node.nim

@@ -1161,7 +1161,7 @@ proc createWalletInteractively(
 programMain:
   var config = makeBannerAndConfig(clientId, BeaconNodeConf)
 
-  setupMainProc(config.logLevel)
+  setupLogging(config.logLevel, config.logFile)
 
   if config.eth2Network.isSome:
     let

beacon_chain/beacon_node.nim.cfg

@@ -1,3 +1,4 @@
+-d:"chronicles_sinks=textlines,json[file]"
 -d:"chronicles_runtime_filtering=on"
 -d:"chronicles_default_output_device=dynamic"
 

beacon_chain/conf.nim

@@ -41,6 +41,10 @@ type
       desc: "Sets the log level"
       name: "log-level" }: string
 
+    logFile* {.
+      desc: "Specifies a path for the written Json log file"
+      name: "log-file" }: Option[OutFile]
+
     eth2Network* {.
       desc: "The Eth2 network to join"
       name: "network" }: Option[string]
@@ -351,6 +355,10 @@ type
       desc: "Sets the log level."
       name: "log-level" }: string
 
+    logFile* {.
+      desc: "Specifies a path for the written Json log file"
+      name: "log-file" }: Option[OutFile]
+
     dataDir* {.
       defaultValue: config.defaultDataDir()
       desc: "The directory where nimbus will store all blockchain data"

beacon_chain/nimbus_binary_common.nim

@@ -9,18 +9,18 @@
 
 import
   # Standard library
-  tables, random, strutils,
+  tables, random, strutils, os, typetraits,
 
   # Nimble packages
-  chronos,
+  chronos, confutils/defs,
   chronicles, chronicles/helpers as chroniclesHelpers,
 
   # Local modules
   spec/[datatypes, crypto], eth2_network, time
 
-proc setupMainProc*(logLevel: string) =
+proc setupLogging*(logLevel: string, logFile: Option[OutFile]) =
   when compiles(defaultChroniclesStream.output.writer):
-    defaultChroniclesStream.output.writer =
+    defaultChroniclesStream.outputs[0].writer =
       proc (logLevel: LogLevel, msg: LogOutputStr) {.gcsafe, raises: [Defect].} =
         try:
           stdout.write(msg)
@@ -29,6 +29,23 @@ proc setupMainProc*(logLevel: string) =
 
   randomize()
 
+  if logFile.isSome:
+    when defaultChroniclesStream.outputs.type.arity > 1:
+      block openLogFile:
+        let
+          logFile = logFile.get.string
+          logFileDir = splitFile(logFile).dir
+        try:
+          createDir logFileDir
+        except CatchableError as err:
+          error "Failed to create directory for log file", path = logFileDir, err = err.msg
+          break openLogFile
+
+        if not defaultChroniclesStream.outputs[1].open(logFile):
+          error "Failed to create log file", logFile
+    else:
+      warn "The --log-file option is not active in the current build"
+
   try:
     let directives = logLevel.split(";")
     try:

beacon_chain/validator_client.nim

@@ -200,7 +200,7 @@ proc onSlotStart(vc: ValidatorClient, lastSlot, scheduledSlot: Slot) {.gcsafe, a
 programMain:
   let config = makeBannerAndConfig("Nimbus validator client v" & fullVersionStr, ValidatorClientConf)
 
-  setupMainProc(config.logLevel)
+  setupLogging(config.logLevel, config.logFile)
 
   case config.cmd
   of VCNoCommand:

beacon_chain/validator_client.nim.cfg

@@ -1,3 +1,4 @@
+-d:"chronicles_sinks=textlines,json[file]"
 -d:"chronicles_runtime_filtering=on"
 -d:"chronicles_default_output_device=dynamic"