aah Log Configuration

This document describes aah log configurations. Typically log configuration done at environment profile level.

Learn about aah configuration syntax.

Table of Contents


List of aah supported log patterns. It used to compose log entry.

  level     - outputs ERROR, WARN, FATAL, PANIC, INFO, DEBUG, TRACE
  appname   - outputs Application Name
  insname   - outputs Application Instance Name
  reqid     - outputs Request ID from HTTP header
  principal - outputs Logged-In subject primary principal value
  time      - outputs local time as per format supplied
  utctime   - outputs UTC time as per format supplied
  longfile  - outputs full file name: /a/b/c/d.go
  shortfile - outputs final file name element: d.go
  line      - outputs file line number: L23
  message   - outputs given message along supplied arguments if they present
  fields    - outputs field values into log entry
  custom    - outputs string as-is into log entry

Note: Log pattern is not applicable to JSON log format.


pattern = "%time:2006-01-02 15:04:05 %level:-5 %shortfile %line %custom:- %message"


log { ... } section configuration goes in env/dev.conf (dev { ... }), env/prod.conf (prod { ... }), etc.

# -----------------------------------------------------------------------------
# Log Configuration
# Doc: https://docs.aahframework.org/logging.html
# Doc: https://docs.aahframework.org/log-config.html
# -----------------------------------------------------------------------------
log {
  # Receiver is used to configure where is log values gets logged to. 
  # aah supports `console` and `file` receivers. Hooks for extension.
  # Default value is `console`.
  receiver = "file"

  # Level indicates the logging levels like `ERROR`, `WARN`, `INFO`, `DEBUG`,
  # `TRACE`, FATAL and PANIC. Config value can be in lowercase or uppercase.
  # Default value is `debug`.
  level = "warn"

  # Format is to define log entry output format. Supported formats are `text` and `json`.
  # Default value is `text`.
  format = "json"

  # Pattern is used to configure log entry format via receivers
  # into receivers. Learn more about flags
  # and format - https://docs.aahframework.org/log-config.html#pattern
  # Default value is `%time:2006-01-02 15:04:05.000 %level:-5 %appname %insname %reqid %principal %message %fields`
  pattern = "%time:2006-01-02 15:04:05.000 %level:-5 %appname %insname %reqid %principal %message %fields"

  # File attribute is applicable only to `file` receiver type.
  # Default value is `aah-log-file.log`.
  file = "appname.log"

  # Rotate config section is applicable only to `file` receiver type.
  # Default rotation is 'daily'.
  rotate {
    # Policy is used to determine rotate policy. aah supports `daily`,
    # `lines` and `size` policies.
    # Default value is `daily`.
    policy = "daily"

    # This is applicable only to if `mode` is `size`.
    # Default value is 100MB.
    #size = 500

    # This is applicable only to if `mode` is `lines`.
    # Default value is unlimited.
    #lines = 100000

Example of configuring Rotation Policy

# daily rotation, it's default one.
rotate {
  policy = "daily"
# size based rotation
rotate {
  policy = "size"
  size = "512mb"
# line based rotation
rotate {
  policy = "lines"
  lines = 100000