logging, colors, terminal width and pretty-print

waflib.Logs.zones = []

See waflib.Logs.log_filter

waflib.Logs.verbose = 0

Global verbosity level, see waflib.Logs.debug() and waflib.Logs.error()


If 1 is given, then the system will perform a few verifications before enabling colors, such as checking whether the interpreter is running in a terminal. A value of zero will disable colors, and a value above 1 will force colors.

Parameters:use (integer) – whether to enable colors or not

Returns the console width in characters.

Returns:the number of characters per line
Return type:int

Returns the ansi sequence corresponding to the given color name. An empty string is returned when coloring is globally disabled.

Parameters:cl (string) – color name in capital letters
class waflib.Logs.color_dict[source]

Bases: object

attribute-based color access, eg: colors.PINK

class waflib.Logs.log_filter(name='')[source]

Bases: logging.Filter

Waf logs are of the form ‘name: message’, and can be filtered by ‘waf –zones=name’. For example, the following:

from waflib import Logs
Logs.debug('test: here is a message')

Will be displayed only when executing:

$ waf --zones=test

Filters log records by zone and by logging level

Parameters:rec – log entry
class waflib.Logs.log_handler(stream=None)[source]

Bases: logging.StreamHandler

Dispatches messages to stderr/stdout depending on the severity level


Delegates the functionality to waflib.Log.log_handler.emit_override()

emit_override(record, **kw)[source]

Writes the log record to the desired stream (stderr/stdout)

class waflib.Logs.formatter[source]

Bases: logging.Formatter

Simple log formatter which handles colors


Formats records and adds colors as needed. The records do not get a leading hour format if the logging level is above INFO.

waflib.Logs.log = None

global logger for Logs.debug, Logs.error, etc

waflib.Logs.debug(*k, **kw)[source]

Wraps logging.debug and discards messages if the verbosity level waflib.Logs.verbose ≤ 0

waflib.Logs.error(*k, **kw)[source]

Wrap logging.errors, adds the stack trace when the verbosity level waflib.Logs.verbose ≥ 2

waflib.Logs.warn(*k, **kw)[source]

Wraps logging.warning

waflib.Logs.info(*k, **kw)[source]

Wraps logging.info


Initializes the logger waflib.Logs.log

waflib.Logs.make_logger(path, name)[source]

Creates a simple logger, which is often used to redirect the context command output:

from waflib import Logs
bld.logger = Logs.make_logger('test.log', 'build')
bld.check(header_name='sadlib.h', features='cxx cprogram', mandatory=False)

# have the file closed immediately

# stop logging
bld.logger = None

The method finalize() of the command will try to free the logger, if any

  • path (string) – file name to write the log output to
  • name (string) – logger name (loggers are reused)
waflib.Logs.make_mem_logger(name, to_log, size=8192)[source]

Creates a memory logger to avoid writing concurrently to the main logger


Frees the resources held by the loggers created through make_logger or make_mem_logger. This is used for file cleanup and for handler removal (logger objects are re-used).

waflib.Logs.pprint(col, msg, label='', sep='\n')[source]

Prints messages in color immediately on stderr:

from waflib import Logs
Logs.pprint('RED', 'Something bad just happened')
  • col (string) – color name to use in Logs.colors_lst
  • msg (string or a value that can be printed by %s) – message to display
  • label (string) – a message to add after the colored output
  • sep (string) – a string to append at the end (line separator)