Python Utility Belt
pub is a tool to help you automate those tasks you don’t want to do manually. It attempts to provide the cleanest, sanest interface for your building, cleaning, and deploying needs.
Pub code is simply python code, allowing you to leverage the skills and tools you’re already familiar with.
Simply install pub, save a pub.py file in a dir, and start coding.
Here’s an example pub.py with two tasks, one to build a project and one to deploy it to a server:
from pub import task from pub.shortcuts import mkdir, cp, rsync @task def build(): mkdir("build") cp("src/binary", "build") @task("build") def deploy(): rsync("build", "user@server:~")
The pub.shortcuts module gives us handy shortcuts to access command-line functionality.
The deploy task depends on the build task, so calling pub deploy will first run the build task, then deploy.
pip install pub
The task decorator in the pub module will be your code’s main interface to pub.
You may create a task with no arguments:
from pub import task @task def zomg(): print "omgbbq"
If you run pub zomg on a pub.py file containing this function, you will see “omgbbq” printed out.
You may also create a task with arguments. Each argument should be the name of another function. The functions in the argument list will all be executed before your task.
from pub import task @task def foo(): print "foo" @task("foo") def bar(): print "bar" @task("foo", "bar") def baz(): print "baz"
If you run pub foo, you will see “foo”.
If you run pub bar, you will see “foo” followed by “bar”.
If you run pub baz, you will see “foo” followed by “bar” followed by “baz”.
Dependencies will be resolved left-to-right, meaning that there’s an implied dependency of each item in a dependency list on its left-hand neighbor. Be careful that you don’t create a circular dependency like so:
from pub import task @task def foo(): print "foo" @task("foo") def bar(): print "bar" @task("bar", "foo") def baz(): print "baz"
In this case, bar depends on foo by the definition of bar, but foo depends on bar by the definition of baz. Pub will be confused about this situation, and resolve it by quitting out with an error.
There are two legal keywords you can use with the task decorator: private and default. private just means that pub -l won’t list your task; if you have a pub.py file like:
from pub import task @task(private=True) def private_func(): pass
and you run pub -l, which normally lists all tasks, private_func will not be listed.
default marks the task as a default action. If you have a pub.py like:
from pub import task @task(default=True) def do_something(): print "got here"
and run pub with no arguments, you should see “got here” printed.
You may mark any number of tasks as default; they will all be run if pub is invoked without arguments. While their dependency information will never be ignored, there is no defined order in which they will be run.
Tasks are documented simply by giving them docstrings. Given this pub.py:
from pub import task @task def gotit(): """You've got it!""" pass @task def noyou(): """I thought you had it.""" pass
We can see how they are displayed by pub:
$ pub -l gotit: You've got it! noyou: I thought you had it.
The pub.shortcuts module builds on @kennethreitz’s fine envoy module to provide a convenient command-line interface for pub.
You can see all the commands that are available in the source, or you can make your own:
from pub.shortcuts import make_shortcut gcc = make_shortcut("gcc") #then use it like so: gcc("-o guildenstern.exe rosencrantz.c")
The invocation of the gcc funciton at the end will translate into gcc -o guildenstern.exe rosencrantz.c and be run.
We can also use our shortcuts to inspect the input, output, and status code of the command; the return value of a shortcut will be an envoy result. Check their documentation for specifics, but basically you can see its output with:
from pub.shortcuts import make_shortcut echo = make_shortcut("echo") out = echo("A conspiracy of cartographers") assert out.std_out == "A conspiracy of cartographers\n"
The pub.shortcuts module also contains one utility function, newer. It simply accepts two arguments and returns True if the mtime of the first is newer than the mtime of the second. Its entire defintion follows:
def newer(f1, f2): return stat(f1).st_mtime > stat(f2).st_mtime
The pub command
The pub command is best described by its --help output:
usage: pub [-h] [-l] [-f FILE] [task [task ...]] Python Utility Belt v0.0.4 positional arguments: task the tasks to run optional arguments: -h, --help show this help message and exit -l list available tasks -f FILE, --pubfile FILE The file to use as a pubfile
Please do! Patches and issues will be gladly accepted.
To run pub’s tests, just run pub test; you’ll need to have installed nose first.
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