NAME

       dgit-downstream-dsc - setting up dgit push for a new distro

INTRODUCTION

       This document is aimed at downstreams of Debian.  It explains how you can publish your
       packages' source code both as traditional Debian source packages, and as git branches,
       using dgit push.  Your users will be able to get the source with dgit clone, or with
       traditional tools such as apt-get source.

       Note that often it is unnecessary to publish traditional source packages.  Debian-format
       source packages can be complex, idiosyncratic and difficult to work with.  You should
       avoid them if you can.  If you do not need to publish source packages, you can work as a
       Debian downstream purely using git branches, (using dgit to get the source from Debian in
       git form).  You can build binaries directly from git, and push package source code as a
       git branch to an ordinary git server.  See dgit-user(7).

       Not every option is covered here.  dgit(1) has a mostly-complete list of config options,
       although not always with useful descriptions.

NAMES

       You need to choose some names.

       distro name
           dgit understands each thing it interacts with as a distro.  So in dgit terms, you are
           setting up a distro.

           You need a name for yourself (ie for your distro).  The name will appear in the git
           tags made by your tools, and in configuration settings.  It must be globally unique
           across all people and institutions who use dgit.

           You could choose your organisation's domain name, or a part of it if you think that is
           going to be very unique.

           The distro name may contain ascii alphanumerics and . + -, although - may be confusing
           and is probably best avoided.  Try to avoid uppercase letters (and underscore): you
           will be typing this name a lot.

           For example, if you were the Free Software Foundation Europe (fsfe.org) you might call
           your distro fsfe or fsfe.org.  In the rest of this document we will write distro for
           your distro name.

       suite names
           In dgit and Debian archive terminology, a suite is a line of development, and/or a
           Debian release.  For example, at the time of writing, Debian has suites like sid aka
           unstable, buster aka testing, and stretch aka stable.  There are also ancillary suites
           like stretch-security.

           If your releases align with Debian's releases, then your suites should contain the
           Debian suite names.  Do not use just the Debian names.  That will cause confusion.
           Instead, prepend your organisation's name and a hyphen.  For example, FSFE might end
           up with suites like fsfe-stretch.

           Suite names end up in git ref and branch names, and on dgit command lines.  Suite
           names can contain alphanumerics and "-".  Other characters may work but are not
           recommended.

SERVICES

       You will need to run two parallel services:

       git server
           This will hold the git branches accessed by dgit.

           Everyone who will use dgit push needs to be able to update refs/dgit/suite (note, not
           refs/heads/dgit/suite) on that server, and to make tags distro/version and
           archive/distro/version.  Normally this would be done over ssh.

           The server may host other branches and tags too.  So this might be your ordinary git
           server, or an instance of a git hosting system.

           Everyone who obtains one of your source packages, or who will run dgit clone and  dgit
           fetch, needs to have at least read access to the git server.  Ideally everything would
           be published via the git smart https protocol.

           The git server name, and public git url structure, should be chosen so they will not
           need to change in the future.  Best is to give the git server a DNS name of its own.

           Debian's dgit git server has special access control rules, implemented in dgit-repos-
           server and dgit-repos-policy-debian in the package dgit-infrastructure.  but in most
           installations this is not needed.  If there is no or little distinction between (i)
           developers who are entitled to upload (push) and (ii) repository administrators, then
           it is sufficient to provide a git server with a unix account for each user who will be
           pushing, perhaps using ssh restricted commands.

       Debian-format archive (repository)
           This holds the source packages.  You will probably use the same archive to host your
           binaries, and point your apt at it.

           dgit uses the term archive for this.

           There are a variety of tools for creating and managing a Debian-format archive.  In
           this document we will assume you are using reprepro.

           Setting up reprepro is not covered in this tutorial.  Instead, we assume you already
           have reprepro working.

           You should also write appropriate dput configuration, since dgit uses dput to upload
           packages to the archive.  This will involve choosing a dput host name.  That's
           probably your distro name, distro.

CONFIGURATION

       When you have all of the above set up, you are ready to explain to dgit how to access your
       systems.

       dgit is configured via git's configuration system, so this is done with git configuration.
       See git-config(1).

       Below, each heading is one or more git config keys.  bold is literal text and italics is
       things that vary.  In the descriptions of the effects of config settings, we refer to the
       config values "like this".

       dgit-distro.distro.git-url, .git-url-suffix
           Specify the publicly accessible git URLs for your dgit git server.  The urls generated
           are "git-url"/package"git-url-suffix"

           The url should be stable, and publicly accessible, because its name is published in
           .dsc files.  (Note that if you make modified versions of packages from Debian, the
           copyleft licences used for Free Software often require you to permit your users,
           employees, and downstreams to further distribute your modified source code.)

       dgit-distro.distro/push.git-host
           The domain name of your git server's ssh interface.

       dgit-distro.distro/push.git-user-force dgit-distro.distro/push.username
           Some git hosting systems expect everyone to connect over ssh as the same user, often
           git.  If this is the case, set "git-user-force" to that user.

           If you have a normal git over ssh arrangement, where people ssh as themselves, leave
           "git-user-force" unset.  If a user wishes to override the username (for example, if
           their local username is not the same as on the server) they can set "username".

       dgit-distro.distro/push.git-url
           Set this to the empty string.  This will arrange that push accesses to the ssh server
           will use "/push.git-host", etc.

       dgit-distro.distro/push.git-proto git+ssh://
       "dgit-distro."distro/push.git-path
           The path to your repositories.  dgit push will try to push to
           "git-proto"["git-user-force"|"username"@]"git-path"/package.git

       dgit-distro.distro.git-check, .git-check-suffix
           dgit clone needs to be able to tell whether there is yet a git repository for a
           particular package.

           If you always have a git repository for every package in your archive, perhaps because
           you never use dput/dupload, and always dgit push, set "git-check" to true.

           Otherwise, set "git-check" to a url prefix - ideally, https.  dgit clone will try to
           fetch "git-check"/package"git-check-suffix" and expect to get either some successful
           fetch (it doesn't matter what) or a file not found error (http 404 status code).
           Other outcomes are fatal errors.

           If your git server runs cgit, then you can set "git-check" to the same as "git-url",
           and "git-check-suffix" to /info/refs.

       dgit-distro.distro/push.git-check, /push.git-create
           dgit push also needs to be able to check whether the repo exists.

           You can set both of these to ssh-cmd, which will use an ssh shell command to test
           repository existence.  Or leave them unset, and dgit push will use the readonly
           details.  If repositories are created automatically on push, somehow, you can set
           "git-create" to true.

       dgit-distro.distro.upload-host
           What host value to pass to dput, to upload.

           This is a nickname, not the real host name.  You need to provide everyone who will
           push with an appropriate dput configuration.  See dput.cf(5).

           A good nickname for your upload host is your distro name distro.

       dgit-distro.distro.mirror
           Set this to the url of your source package archive.  This is the same string as
           appears in the 2nd field of each sources.list entry.

       dgit-distro.distro.archive-query, .archive-query-url
           If you have a smallish distro, set "archive-query" to aptget: (with a colon).

           If your distro is large (eg, if it contains a substantial fraction of Debian) then
           this will not be very efficient: with this setting, dgit often needs to download and
           update Sources files.

           For large distros, it is better to implement the Debian archive ftpmaster API.  See
           <https://api.ftp-master.debian.org/>, and set "archive-query" to ftpmasterapi: (with a
           colon) and "archive-query-url" to your API base URL.  dgit uses these queries: suites,
           dsc_in_suite/isuite/package and file_in_archive/pat (so you need not implement
           anything else).

           Alternatively, if your system supports the rmadison protocol, you can set
           "archive-query" to madison:[madison-distro].  dgit will invoke rmadison -umadison-
           distro.

       dgit-suite.suite.distro distro
           Set this for every one of your suites.  You will have to update this when new suites
           are created.  If you forget, your users can explicitly specify -d distro to dgit.

TEMPLATE GIT REPOSITORY

       When dgit push is used for package for the first time, it must create a git repository on
       the git server.

       If "git-create" is set to ssh-cmd, dgit will use the user's shell access to the server to
       cp -a _template.git package.git.  So you should create _template.git with suitable
       contents.

       Note that the ssh rune invoked by dgit does not do any locking.  So if two people dgit
       push the same package at the same time, there will be lossage.  Either don't do that, or
       set up dgit-repos-server.

SSH COMMANDS

       When a user who can push runs dgit, dgit uses ssh to access the git server.

       To make use of ssh restricted command easier, and for the benefit of dgit-repos-server,
       dgit's ssh commands each start with a parseable commentish rune.

       The ssh commands used by dgit are these:

       : dgit distro git-check package ;...
           Test whether package has a git repo on the server already.  Should print 0 or 1 and a
           newline, and exit status zero in either case.  The rest of the command, after ;, is a
           shell implementation of this test.  Used when "git-check" is set to ssh-cmd.

       : dgit distro git-create package ;...
           Create the git repository for package on the server.  See "TEMPLATE GIT REPOSITORY",
           above.  The rest of the command is an appropriate invocation of cd and cp.  Used when
           "git-create" is set to ssh-cmd.

       git-receive-pack..., git-upload-pack...
           dgit invokes git to access the repository; git then runs these commands.  Note that
           dgit push will first do a git fetch over ssh, so you must provide upload-pack as well
           as receive-pack.

       (There are also other ssh commands which are historical or obscure.)

SEE ALSO

       dgit(1)