Version Control Systems

ID: 879abc56-8968-43cc-8bee-76118b398eaf
CREATED: <2025-02-16 Sun 20:24>

• as of 2022 I've been using hg-fast-export to convert my hg repos to git so they can be mirrored on github (as well as codeberg)

It is quite easy to integrate this process with CI:

# >> make mirror
# root path
ROOT=$(dir $(abspath $(firstword $(MAKEFILE_LIST))))
# this is wherever you pulled hg-fast-export to
STASH=~/stash
# path to hg-fast-export binary
FE=$(STASH)/fast-export/hg-fast-export.sh
mirror:$(FE) $(ROOT) out
mkdir -p out/$@;
git init out/$@;
cd out/$@ && \
git config core.ignoreCase false && git config push.followTags true && \
# run with '-M default' for default branch
$(FE) -r $(ROOT) -M default && git checkout HEAD && \
git remote add gh git@github.com:richardwesthaver/mpk.git && \
git push gh --all;
@rm -rf out/$@;

• Two different plugins - git and hggit, different features
  • 'git' usage will treat a cloned repo as a git repo and just pull branch heads into mercurial (.git directory and .hg directory present at root)
  • 'hggit' will convert all changesets, branches, etc (.hg directory only)
    • pulling changesets can be incredibly slow at times
    • unlike vanilla hg, pulling from a git repo with hggit does NOT support revision CLI flag ('-r 100' will not work), so the standard method of doing an incremental pull is not possible
    • expect unexpected behaviors. always have backups.
  • hggit will often pull the 'github-pages' branch from repos using GitHub Sites and treat it as the default branch in the resulting clone. To make the repo usable you need to update to the 'master' bookmark, and use that as default

ID: 11bb8531-a936-4b77-a29e-1e2d35436836
CREATED: <2025-02-16 Sun 20:26>

Hg Bundles are a more powerful version of git bundles and come in two flavors: Clonebundles and Pullbundles. They share a common format, support the bundle and unbundle commands, but are also used to provision their own commands: hg clone and hg pull respectively. Bundles are advertised via manifest files located in the .hg directory of a repo, and support a variety of compression backends via the BUNDLESPEC value specified in manifest.

• Bundlespec
  • none-v2
  • gzip-v2
  • zstd-v2
  • stream-v2
• Manifests
  • clonebundles.manifest
  • pullbundles.manifest
  • manifest.json

ID: b750a5f3-f12c-439a-a730-1dcea8951d43
CREATED: <2025-02-16 Sun 20:27>

Hosting with vanilla Mercurial is quite similar to vanilla Git. hg serve is basically the equivalent to git instaweb. Where they differ is in the out-of-box solutions - Git has cgit, GitLab, Gitolite, git.sr.ht, etc. Mercurial has hg.sr.ht, and just recently Heptapod, which is not production-ready.

My experience with self-hosting the sr.ht eco-system was far from a good one due to conflicting dependencies, package manager incompatibility, and some classic PHP craziness. The Heptapod docker container took eons just to build tests, so I just gave up on that for now but will be on the look out for new developments with that project. So what we're really left with is the built-in tools. Lucky for us, we have the hgweb scripts at our disposal.

Here's the relevant docs covering all topics in this section. They are all must-reads if you plan on exposing a Mercurial server to the public.

• PublishingRepositories - Mercurial
• SecuringRepositories - Mercurial
• AuthorizingUsers - Mercurial

• hgweb + wsgi + nginx
  The hgweb script is used for deployment of the server via CGI or WSGI. The WSGI setup is a bit more involved, but according to the docs:

  (!) Much better performance can be achieved by using WSGI instead of CGI.

  This section covers the WSGI (pronounced whis-gee) setup, specifically for Nginx. The docs have better examples for Apache servers, so you do need to go off the beaten path to find just the right values to set in Nginx. The following setup worked for https://hg.rwest.io running Arch Linux.

  • dependencies
    
    • uwsgi and uwsgi-plugin-python are required for the hgweb.wsgi script.
    • nginx is used here, but…
    • apache package is needed if you want to use htpasswd while setting up HTTP Authentication. SSH auth only or public hosts don't need this.

  • /etc/uwsgi/hgweb.ini
    This is a UWSGI service configuration file - the hgweb.wsgi script needs to be located in the directory specified by chdir. If you are using systemd, try enabling the service with systemctl enable uwsgi@hgweb.service, and check the logs for any errors. The service calls the hgweb.wsgi script, which serves all repos configured via hgweb.conf.

    [uwsgi]
    master = true
    ; max-requests = 1000
    ; logto = {log file path}/hgweb-uwsgi.log
    uid = hgweb ; set process owner
    gid = hgweb
    stats = /run/uwsgi/stats.sock
    chmod-socket = 666
    cap = setgid,setuid
    ; https://www.mercurial-scm.org/wiki/PublishRepositoriesOnNginx
    plugins = python
    socket = /run/uwsgi/hgweb.sock
    chdir = /home/hgweb/hg
    wsgi-file = hgweb.wsgi
    ; https://stackoverflow.com/questions/15878176/uwsgi-invalid-request-block-size
    ; http://uwsgi-docs.readthedocs.io/en/latest/ThingsToKnow.html
    ; buffer-size = 65535
    

  • hgweb.wsgi
    The config path must be a byte string, and an absolute path. This script needs to be in the same directory as hgweb.conf.

    #!/usr/bin/env python3
    config = b"/home/hgweb/hgweb.conf"
    # Uncomment to send python tracebacks to the browser if an error occurs:
    #import cgitb; cgitb.enable()
    # enable demandloading to reduce startup time
    from mercurial import demandimport; demandimport.enable()
    from mercurial.hgweb import hgweb
    application = hgweb(config)
    

  • hgweb.conf
    Mercurial web server configuration file. Setting staticurl to /static allows us to pass serving of static content to Nginx, which is faster and has better caching controls.

    [web]
    encoding = UTF-8
    baseurl = https://hg.rwest.io
    contact = some_dude
    templates = theme
    style = spartan
    logourl = https://rwest.io
    staticurl = /static
    descend = True
    collapse = True
    [paths]
    / = src/*
    

  • /etc/nginx/sites-enabled/hg.conf
    Note that none of the extra uwsgi params from mercurial docs are used here, only the default uwsgi_params files provided by Nginx.

      server {
        server_name hg.rwest.io;
        listen 443 ssl;
        ssl_certificate fullchain.pem;
        ssl_certificate_key privkey.pem;
        ssl_protocols TLSv1.1 TLSv1.2 TLSv1.3;
        ssl_ciphers HIGH:!aNULL:!MD5;
        root /home/hgweb/hg;
        location / {
          limit_except GET HEAD {
            auth_basic "Mercurial userspace";
            auth_basic_user_file /home/hgweb/hg/hg.htpasswd;
          }
        include uwsgi_params;
        uwsgi_pass unix:/run/uwsgi/hgweb.sock;    
      }
    
      location /static {
        alias /home/hgweb/hg/static;
        expires 30d;
      }
    }
    

ID: a62a2e17-8167-4812-b5ec-f4f9ef698f56
CREATED: <2025-02-14 Fri 21:21>

[2025-02-14 Fri 21:21] – Using Mercurial Extensions