Mercurial scripting with python

Question

Hello,

I am trying to get the mercurial revision number/id (it's a hash not a number) programmatically in python.

The reason is that I want to add it to the css/js files on our website like so:

<link rel="stylesheet" href="example.css?{% mercurial_revision "example.css" %}" />

So that whenever a change is made to the stylesheet, it will get a new url and no longer use the old cached version.

OR if you know where to find good documentation for the mercurial python module, that would also be helpful. I can't seem to find it anywhere.

My Solution

I ended up using subprocess to just run a command that gets the hg node. I chose this solution because the api is not guaranteed to stay the same, but the bash interface probably will:

import subprocess

def get_hg_rev(file_path):
    pipe = subprocess.Popen(
        ["hg", "log", "-l", "1", "--template", "{node}", file_path],
        stdout=subprocess.PIPE
        )
    return pipe.stdout.read()

example use:

> path_to_file = "/home/jim/workspace/lgr/pinax/projects/lgr/site_media/base.css"
> get_hg_rev(path_to_file)
'0ed525cf38a7b7f4f1321763d964a39327db97c4'

Answer 1

give a try to the keyword extension

Answer 2

Do you mean this documentation?
Note that, as stated in that page, there is no official API, because they still reserve the right to change it at any time. But you can see the list of changes in the last few versions, it is not very extensive.

Answer 3

It's true there's no official API, but you can get an idea about best practices by reading other extensions, particularly those bundled with hg. For this particular problem, I would do something like this:

from mercurial import ui, hg
from mercurial.node import hex

repo = hg.repository('/path/to/repo/root', ui.ui())
fctx = repo.filectx('/path/to/file', 'tip')
hexnode = hex(fctx.node())