Data type specification for MDC fields

[mp911de]

MDC fields contain various data types. String and numeric types are currently passed over GELF. When a field contains a numeric content (such as 42 or 12.34) the numeric value is parsed using Long.parseLong and Double.parseDouble to determine a parseable format.

Users of Graylog run into issues as soon as the data type of a particular field varies. logstash-gelf requires a possibility to specify fixed types to support Graylog > 1.2.x.

The type specification is not needed in most cases so it should be opt-in but once a type is set, it must be honored. A possible style to define types could be either:

mdcFields=Application,Version=long,SomeOtherFieldName=double,SomeOtherFieldName2=String

with colon:

mdcFields=Application,Version:long,SomeOtherFieldName:double,SomeOtherFieldName2:String

or

mdcFields=Application,Version,SomeOtherFieldName,SomeOtherFieldName2
mdcFieldTypes=Version=long,SomeOtherFieldName=double,SomeOtherFieldName2=String

includeFullMdc=true
mdcFieldTypes=Version=long,SomeOtherFieldName=double,SomeOtherFieldName2=String

Types

• long
• double
• String

Open points

• What if a value cannot be parsed (e.g. type double but value is fadsfds)?
  • Possibility 1: Omit the field
  • Possibility 2: Return zero value

Reported by @kebers

[mp911de]

Implemented.