[#17] implement compile time topic log level filter

README.md

@@ -295,6 +295,13 @@ When the list includes multiple topics, any of them is considered a match.
 > In both contexts, the list of topics is written as a comma or space-separated
 string of case-sensitive topic names.
 
+In the list of topics, you can also optionally provide a log level after the
+topic, separated with a colon from the topic. If a log level is provided it will
+overrule the `chronicles_log_level` setting. The log level can be defined as
+`LogLevel` values or directly as the corresponding integer values.
+
+e.g. `-d:chronicles_enabled_topics:MyTopic:DEBUG,AnotherTopic:5`
+
 ### chronicles_required_topics
 
 Similar to `chronicles_enabled_topics`, but requires the logging statements

chronicles.nim

@@ -165,7 +165,7 @@ macro logIMPL(lineInfo: static InstInfo,
               severity: static[LogLevel],
               scopes: typed,
               logStmtBindings: varargs[untyped]): untyped =
-  if not loggingEnabled or severity < enabledLogLevel: return
+  if not loggingEnabled: return
   clearEmptyVarargs logStmtBindings
 
   # First, we merge the lexical bindings with the additional
@@ -184,6 +184,7 @@ macro logIMPL(lineInfo: static InstInfo,
   # This is the compile-time topic filtering code, which has a similar
   # logic to the generated run-time filtering code:
   var enabledTopicsMatch = enabledTopics.len == 0
+  var enabledTopicsLevel = enabledLogLevel
   var requiredTopicsCount = requiredTopics.len
   var topicsNode = newLit("")
   var activeTopics: seq[string] = @[]
@@ -196,15 +197,19 @@ macro logIMPL(lineInfo: static InstInfo,
     if topicsNode.kind notin {nnkStrLit, nnkTripleStrLit}:
       error "Please specify the 'topics' list as a space separated string literal", topicsNode
 
-    activeTopics = topicsNode.strVal.split(Whitespace)
+    activeTopics = topicsNode.strVal.split({','} + Whitespace)
 
     for t in activeTopics:
       if t in disabledTopics:
         return
-      elif t in enabledTopics:
-        enabledTopicsMatch = true
-      elif t in requiredTopics:
-        dec requiredTopicsCount
+      else:
+        for topic in enabledTopics:
+          if topic.name == t:
+            enabledTopicsMatch = true
+            if topic.logLevel != None:
+              enabledTopicsLevel = topic.logLevel
+        if t in requiredTopics:
+          dec requiredTopicsCount
 
   # Handling file name and line numbers on/off (lineNumbersEnabled) for particular log statements
   if finalBindings.hasKey("chroniclesLineNumbers"):
@@ -215,7 +220,7 @@ macro logIMPL(lineInfo: static InstInfo,
     useLineNumbers = chroniclesLineNumbers == "true"
     finalBindings.del("chroniclesLineNumbers")
 
-  if not enabledTopicsMatch or requiredTopicsCount > 0:
+  if not enabledTopicsMatch or requiredTopicsCount > 0 or severity < enabledTopicsLevel:
     return
 
   var code = newStmtList()

chronicles/options.nim

@@ -88,6 +88,10 @@ type
   Configuration* = object
     streams*: seq[StreamSpec]
 
+  Topic* = object
+    name*: string
+    logLevel*: LogLevel
+
 const defaultChroniclesStreamName* = "defaultChroniclesStream"
 
 proc handleYesNoOption(optName: string,
@@ -124,10 +128,26 @@ template handleEnumOption(E, varName: untyped): auto =
 
 template topicsAsSeq(topics: string): untyped =
   when topics.len > 0:
-    topics.split(Whitespace)
+    topics.split({','} + Whitespace)
   else:
     newSeq[string](0)
 
+template topicsWithLogLevelAsSeq(topics: string): untyped =
+  var sequence = newSeq[Topic](0)
+  when topics.len > 0:
+    for topic in split(topics, {','} + Whitespace):
+      var values = topic.split(':')
+      if values.len > 1:
+        if values[1].isDigit:
+          sequence.add(Topic(name: values[0],
+                             logLevel: LogLevel(parseInt(values[1]))))
+        else:
+          sequence.add(Topic(name: values[0],
+                             logLevel: handleEnumOption(LogLevel, values[1])))
+      else:
+        sequence.add(Topic(name: values[0], logLevel: None))
+  sequence
+
 proc logFormatFromIdent(n: NimNode): LogFormat =
   let format = $n
   case format.toLowerAscii
@@ -285,7 +305,7 @@ const
 
   textBlockIndent* = repeat(' ', chronicles_indent)
 
-  enabledTopics*  = topicsAsSeq chronicles_enabled_topics
+  enabledTopics*  = topicsWithLogLevelAsSeq chronicles_enabled_topics
   disabledTopics* = topicsAsSeq chronicles_disabled_topics
   requiredTopics* = topicsAsSeq chronicles_required_topics
   lineNumbersEnabled* = handleYesNoOption chronicles_line_numbers