Internal subroutines for e.g. aborting execution with an error message, or performing indenting on multiline output.


Abort execution, print msg to stderr and exit with error status (1.)

This function currently makes use of SystemExit in a manner that is similar to sys.exit (but which skips the automatic printing to stderr, allowing us to more tightly control it via settings).

Therefore, it’s possible to detect and recover from inner calls to abort by using except SystemExit or similar.

fabric.utils.error(message, func=None, exception=None, stdout=None, stderr=None)

Call func with given error message.

If func is None (the default), the value of env.warn_only determines whether to call abort or warn.

If exception is given, it is inspected to get a string message, which is printed alongside the user-generated message.

If stdout and/or stderr are given, they are assumed to be strings to be printed.

fabric.utils.fastprint(text, show_prefix=False, end='', flush=True)

Print text immediately, without any prefix or line ending.

This function is simply an alias of puts with different default argument values, such that the text is printed without any embellishment and immediately flushed.

It is useful for any situation where you wish to print text which might otherwise get buffered by Python’s output buffering (such as within a processor intensive for loop). Since such use cases typically also require a lack of line endings (such as printing a series of dots to signify progress) it also omits the traditional newline by default.


Since fastprint calls puts, it is likewise subject to the user output level.

New in version 0.9.2.

See also


fabric.utils.indent(text, spaces=4, strip=False)

Return text indented by the given number of spaces.

If text is not a string, it is assumed to be a list of lines and will be joined by \n prior to indenting.

When strip is True, a minimum amount of whitespace is removed from the left-hand side of the given string (so that relative indents are preserved, but otherwise things are left-stripped). This allows you to effectively “normalize” any previous indentation for some inputs.


Check if a stream is a tty.

Not all file-like objects implement the isatty method.

fabric.utils.puts(text, show_prefix=None, end='\n', flush=False)

An alias for print whose output is managed by Fabric’s output controls.

In other words, this function simply prints to sys.stdout, but will hide its output if the user output level is set to False.

If show_prefix=False, puts will omit the leading [hostname] which it tacks on by default. (It will also omit this prefix if env.host_string is empty.)

Newlines may be disabled by setting end to the empty string (''). (This intentionally mirrors Python 3’s print syntax.)

You may force output flushing (e.g. to bypass output buffering) by setting flush=True.

New in version 0.9.2.

See also



Print warning message, but do not abort execution.

This function honors Fabric’s output controls and will print the given msg to stderr, provided that the warnings output level (which is active by default) is turned on.