Command line interface

You can execute arbitrary scripts with instrumentation enabled using the pyc command line tool (installed as both pyc and pyccolo). For example, to run some script bar.py under the optional-chaining example tracer:

# bar.py
bar = None
# prints `None` since bar?.foo coalesces to `None`
print(bar?.foo)

$ pyc bar.py -t pyccolo.examples.optional_chaining.ScriptOptionalChainer

You can also run bar as a module (indeed, pyc does this internally when given a file):

$ pyc -m bar -t pyccolo.examples.optional_chaining.ScriptOptionalChainer

The -t value is a fully-qualified reference to a tracer class. Note that we use ScriptOptionalChainer rather than the bare OptionalChainer: because pyc runs your file through Pyccolo’s import machinery, the tracer must opt that file in by overriding should_instrument_file() (which ScriptOptionalChainer does, and OptionalChainer does not — see Instrumenting imported modules).

You can specify multiple tracer classes after -t; in case you were not already aware, Pyccolo is composable! (see Composing tracers).

Options

Pyccolo command line tool.

usage: pyc [-h] [-m MODULE] -t TRACER [TRACER ...] [script]

Positional Arguments

script

Script to run with instrumentation.

Named Arguments

-m, --module

The module to run, if script not specified.

-t, --tracer

Tracers to use for instrumentation.