don't write about alternatives; best done elsewhere.
ACCESS.CONF
Out of the box, there are just two kinds of users: the ones with keys in
"keys/root" and those in "keys/users". However, you can change this by
editing "access.conf". There are two "access.conf" files, one in
"/etc/mercurial-server" and one in "hgadmin"; the two are simply
concatenated before being read.
Each line of access.conf has the following syntax:
<rule> <condition> <condition> ...
Rule is one of
init - allow any operation, including the creation of new repositories
write - allow reads and writes to this file in this repository
read - allow the repo to be read but reject matching writes
deny - deny all requests
A condition is a globpattern matched against a relative path. The two most
important conditions are
user=<globpattern> - user's key
repo=<globpattern> - repo (as the user supplies it)
The first rule in the file which has all its conditions satisfied is used
to determine whether an action is allowed. If no rule is matched the
request is denied.
"*" only matches one directory level, where "**" matches as many as you
want. More precisely, "*" matches zero or more characters not including "/"
while "**" matches zero or more characters including "/".
Blank lines and lines that start with "#" are ignored.
access.conf ships with the following contents:
init user=root/**
deny repo=hgadmin
write user=users/**
This means: keys in "root" can do anything; keys in "users" cannot create
repositories, cannot even read the hgadmin repository, but can read and
write any other repository; no other key has any access.
More advanced access configuration is covered in file-conditions.