mercurial multiple usernames in hgrc

I am accessing multiple mercurial repositories and based on the host name, I want to configure with what name and email address I appear on each of them.

The obvious solution would be adding the 'username' to the ui section of each repo's hgrc file but I do not want to rely on this as these sandboxes get deleted every now and then.

Therefore, I need a central place where I can keep all this together. I'd ideally like a solution where I can map host names to usernames in the user specific hgrc file (~/.hgrc).

Is this possible?

Regards,

[edit] Yes, @cyon's answer does the job. I've just updated it to handle 'ssh://user@' type urls and also cope when there is no target folder in the clone command.

def merc_host_to_username_mapper(**kwargs):
    host_to_username_map={'bitbucket.org' : 'your name <name@mail.com>'}
    hg_pats = kwargs['pats']
    merc_url = hg_pats[0]

    merc_path_list = merc_url.split('://', 1)
    if len(merc_path_list) == 1:
        #print('ret1')
        return

    merc_sub_path = merc_path_list[-1].split('@',1)[-1]
    while True:
        #print('sub_path: ', merc_sub_path)
        if merc_sub_path in host_to_username_map:
            #print('found path, breaking')
            break
        else:
            if len(merc_sub_path.rsplit('/', 1)) == 1:
                #print('ret2')
                return
            else:
                merc_sub_path = merc_sub_path.rsplit('/', 1)[0]

    if len(hg_pats) is 1:
        for folder in reversed(hg_pats[0].split('/')):
            if folder:
                hg_pats.append(folder)
                #print('breaking ',folder)
                break
        if len(hg_pats) is 1:
            #print('ret3')
            return

    #print('hg_pats: ', hg_pats)
    with open(hg_pats[1] + "/.hg/hgrc", "a") as hgrc:
        print("adding username \'" + host_to_username_map[merc_sub_path] + '\' to hgrc');
        hgrc.write("[ui]\n");
        hgrc.write("username=" + host_to_username_map[merc_sub_path] + "\n");

Solution

You could use a post-clone hook to automate the adding of the 'username' to the ui seciton of each repo's hgrc.

This hook would then give you a place where to keep the centralized mapping from repo to username.

The code could look like this:

~/.hgrc:

[hooks]
post-clone=python:/path/to/script/name_chooser.py:chooser

name_chooser.py:

def chooser(**kwargs):
    map={'https://bitbucket.org/yourrepo' : 'your_user'}
    hg_pats = kwargs['pats']
    if hg_pats[0] not in map:
        return
    with open(hg_pats[1] + "/.hg/hgrc", "a") as hgrc:
        hgrc.write("[ui]\n");
        hgrc.write("username=" + map[hg_pats[0]] + "\n");

The kwargs['pats'] is a list of the arguments to the hg clone command. In this code I assume that you invoke clone like this:

hg clone https://bitbucket.org/yourrepo local_repo_path