Message templates

Message template is the text of a log message that can potentially contain placeholders filled with property values during rendering.

Placeholders are always specified in curly brackets: Response code = {Code}.

During rendering, placeholders are replaced with values of properties with corresponding names:

Response code = {Code} + {"Code": "200"} = Response code = 200

Any mismatched brackets are kept as-is: {key} template renders to the same text.

Any placeholders without corresponding properties are replaced with empty strings.

Double curly brackets can be used to escape occurrences of curly brackets in text: {{key}} template renders to {key} text.

Do not pass a message as a message template.

For example, instead of log.Info(json) you should use log.Info("{Json}", json).

Otherwise, you may have performance issues (due to the internal templates cache) or corrupted messages (due to the rendering stage).