Logging Configuration

Configure logging levels and module-specific logging for Watch Tower. The Watch Tower provides flexible logging configuration through the LOG_LEVEL environment variable. You can control both global and module-specific logging levels.

Log levels

The following log levels are available, from most to least verbose:

TRACE - Most detailed logging
DEBUG - Debug information
INFO - Informational messages
WARN - Warning messages
ERROR - Error messages only

Setting the log level

Set the LOG_LEVEL environment variable to control logging verbosity:

LOG_LEVEL=INFO yarn cli run --config-path ./config.json

LOG_LEVEL=WARN yarn cli run --config-path ./config.json

LOG_LEVEL=DEBUG yarn cli run --config-path ./config.json

LOG_LEVEL=TRACE yarn cli run --config-path ./config.json

Module-specific logging

You can override the log level for specific modules using comma-separated values:

LOG_LEVEL=WARN,chainContext=INFO

This sets the global log level to WARN, but enables INFO level logging for the chainContext module.

Multiple module overrides

Specify multiple module overrides separated by commas:

LOG_LEVEL=WARN,chainContext=INFO,_placeOrder=TRACE

In this example:

Global log level: WARN
chainContext module: INFO
_placeOrder module: TRACE

Regex patterns for logger names

Module names can be regex patterns, allowing fine-grained control over logging:

Pattern matching examples

# Matches: chainContext:processBlock:100:30212964
# Matches: chainContext:processBlock:1:30212964
# Matches: chainContext:processBlock:5:30212964
LOG_LEVEL='chainContext:processBlock:(\d{1,3}):(\d*)$=DEBUG'

# Matches: chainContext:processBlock:100:30212964
# Matches: chainContext:processBlock:1:30212964
# But not: chainContext:processBlock:5:30212964
LOG_LEVEL='chainContext:processBlock:(100|1):(\d*)$=DEBUG'

# Matches any logger starting with "chainContext"
LOG_LEVEL='^chainContext=INFO'

# Matches loggers starting with "checkForAndPlaceOrder"
LOG_LEVEL='^checkForAndPlaceOrder=WARN'

Use single quotes around the LOG_LEVEL value when using regex patterns to prevent shell interpretation of special characters.

Complex logging configuration

Combine multiple techniques for precise control:

LOG_LEVEL="WARN,commands=DEBUG,^checkForAndPlaceOrder=WARN,^chainContext=INFO,_checkForAndPlaceOrder:1:=INFO" yarn cli

This configuration:

Sets global log level to WARN
Enables DEBUG for commands module
Sets WARN for loggers starting with checkForAndPlaceOrder
Sets INFO for loggers starting with chainContext
Sets INFO for _checkForAndPlaceOrder:1: loggers

Using with Docker

When running the Watch Tower in Docker, pass the LOG_LEVEL environment variable:

docker run --rm -it \
  -e LOG_LEVEL=WARN \
  -v "$(pwd)/config.json:/config.json" \
  ghcr.io/cowprotocol/watch-tower:latest \
  run --config-path /config.json

docker run --rm -it \
  -e LOG_LEVEL="WARN,chainContext=INFO" \
  -v "$(pwd)/config.json:/config.json" \
  ghcr.io/cowprotocol/watch-tower:latest \
  run --config-path /config.json

Using with environment files

Create a .env file for persistent configuration:

LOG_LEVEL=WARN

Or with module-specific logging:

LOG_LEVEL=WARN,chainContext=INFO,_placeOrder=TRACE

Then load it with Docker:

docker run --rm -it \
  --env-file .env \
  -v "$(pwd)/config.json:/config.json" \
  ghcr.io/cowprotocol/watch-tower:latest \
  run --config-path /config.json

Common logging patterns

LOG_LEVEL=WARN

LOG_LEVEL=DEBUG

LOG_LEVEL=WARN,chainContext=DEBUG

LOG_LEVEL=WARN,_placeOrder=TRACE,checkForAndPlaceOrder=DEBUG

LOG_LEVEL=ERROR

Tips

Start with WARN in production to reduce log volume
Use DEBUG or TRACE when troubleshooting specific issues
Module-specific logging helps debug particular components without flooding logs
Regex patterns are powerful but require careful escaping in shell commands
Remember to quote complex LOG_LEVEL values containing special characters

BFF

Services

Watch Tower

Logging Configuration

Logging Configuration

Log levels

Setting the log level

Module-specific logging

Multiple module overrides

Regex patterns for logger names

Pattern matching examples

Complex logging configuration

Using with Docker

Using with environment files

Common logging patterns

Tips

​Logging Configuration

​Log levels

​Setting the log level

​Module-specific logging

​Multiple module overrides

​Regex patterns for logger names

​Pattern matching examples

​Complex logging configuration

​Using with Docker

​Using with environment files

​Common logging patterns

​Tips

Logging Configuration

Log levels

Setting the log level

Module-specific logging

Multiple module overrides

Regex patterns for logger names

Pattern matching examples

Complex logging configuration

Using with Docker

Using with environment files

Common logging patterns

Tips