- gracefully handle errors from log parsers

+ they can throw a LogStash::Log::LogParseError now
- handle JSON parse exceptions

lib/log.rb

@@ -15,6 +15,8 @@ module LogStash
                      :pattern_dir]
     attr_accessor :attrs
 
+    LogParseError = Class.new(StandardError)
+
     def initialize(config)
       check_hash_keys(config, REQUIRED_KEYS, OPTIONAL_KEYS)
 

lib/log/json.rb

@@ -23,8 +23,11 @@ module LogStash
       end
 
       def parse_entry(raw_entry)
-        # need to add @LINE
-        res = LogStash::Util::collapse(JSON.parse(raw_entry))
+        begin
+          res = LogStash::Util::collapse(JSON.parse(raw_entry))
+        rescue JSON::ParserError
+          raise LogParseError.new("Invalid JSON: #{$!}: #{raw_entry}")
+        end
         res["@LINE"] = template(@line_format, res)
         fix_date(res)
 

lib/net/servers/parser.rb

@@ -55,11 +55,19 @@ module LogStash; module Net; module Servers
       end
 
       log_type = request.log_type
-      entry = @config.logs[log_type].parse_entry(request.log_data)
+      entry = nil
+      reason = "unknown; parse_entry returned without an exception"
+      begin
+        entry = @config.logs[log_type].parse_entry(request.log_data)
+      rescue LogStash::Log::LogParseError
+        reason = $!
+      end
+
       if !entry
-        @logger.warn "Failed parsing line: #{request.log_data}"
+        @logger.warn "Failed parsing line: #{reason}: #{request.log_data}"
         response.code = 1
-        response.error = "Entry was #{entry.inspect} (log parsing failed)"
+        response.error = "Entry was #{entry.inspect} (log parsing " \
+                         "failed: #{reason})"
         entry = {
           "@NEEDSPARSING" => 1,
           "@LINE" => request.log_data