.. _tutorial-gitfs:

==================================
Git Fileserver Backend Walkthrough
==================================

.. note::

    This walkthrough assumes basic knowledge of Salt. To get up to speed, check
    out the :ref:`Salt Walkthrough <tutorial-salt-walk-through>`.

The gitfs backend allows Salt to serve files from git repositories. It can be
enabled by adding ``git`` to the :conf_master:`fileserver_backend` list, and
configuring one or more repositories in :conf_master:`gitfs_remotes`.

Branches and tags become Salt fileserver environments.

.. note::
    Branching and tagging can result in a lot of potentially-conflicting
    :ref:`top files <states-top>`, for this reason it may be useful to set
    :conf_minion:`top_file_merging_strategy` to ``same`` in the minions' config
    files if the top files are being managed in a GitFS repo.

.. _gitfs-dependencies:

Installing Dependencies
=======================

Both pygit2_ and GitPython_ are supported Python interfaces to git. If
compatible versions of both are installed, pygit2_ will be preferred. In these
cases, GitPython_ can be forced using the :conf_master:`gitfs_provider`
parameter in the master config file.

.. note::
    It is recommended to always run the most recent version of any the below
    dependencies. Certain features of GitFS may not be available without
    the most recent version of the chosen library.

.. _pygit2: https://github.com/libgit2/pygit2
.. _GitPython: https://github.com/gitpython-developers/GitPython

pygit2
------

The minimum supported version of pygit2_ is 0.20.3. Availability for this
version of pygit2_ is still limited, though the SaltStack team is working to
get compatible versions available for as many platforms as possible.

For the Fedora/EPEL versions which have a new enough version packaged, the
following command would be used to install pygit2_:

.. code-block:: bash

    # yum install python-pygit2

Provided a valid version is packaged for Debian/Ubuntu (which is not currently
the case), the package name would be the same, and the following command would
be used to install it:

.. code-block:: bash

    # apt-get install python-pygit2


If pygit2_ is not packaged for the platform on which the Master is running, the
pygit2_ website has installation instructions
`here <pygit2-install-instructions>`_. Keep in mind however that
following these instructions will install libgit2_ and pygit2_ without system
packages. Additionally, keep in mind that :ref:`SSH authentication in pygit2
<pygit2-authentication-ssh>` requires libssh2_ (*not* libssh) development
libraries to be present before libgit2_ is built. On some Debian-based distros
``pkg-config`` is also required to link libgit2_ with libssh2.

.. note::
    If you are receiving the error "Unsupported URL Protocol" in the Salt Master
    log when making a connection using SSH, review the libssh2 details listed
    above.

Additionally, version 0.21.0 of pygit2 introduced a dependency on python-cffi_,
which in turn depends on newer releases of libffi_. Upgrading libffi_ is not
advisable as several other applications depend on it, so on older LTS linux
releases pygit2_ 0.20.3 and libgit2_ 0.20.0 is the recommended combination.

.. warning::
    pygit2_ is actively developed and `frequently makes
    non-backwards-compatible API changes <pygit2-version-policy>`_, even in
    minor releases. It is not uncommon for pygit2_ upgrades to result in errors
    in Salt. Please take care when upgrading pygit2_, and pay close attention
    to the changelog_, keeping an eye out for API changes. Errors can be
    reported on the `SaltStack issue tracker <saltstack-issue-tracker>`_.

.. _pygit2-version-policy: http://www.pygit2.org/install.html#version-numbers
.. _changelog: https://github.com/libgit2/pygit2#changelog
.. _saltstack-issue-tracker: https://github.com/saltstack/salt/issues
.. _pygit2-install-instructions: http://www.pygit2.org/install.html
.. _libgit2: https://libgit2.org/
.. _libssh2: https://www.libssh2.org/
.. _python-cffi: https://pypi.org/project/cffi
.. _libffi: http://sourceware.org/libffi/


RedHat Pygit2 Issues
~~~~~~~~~~~~~~~~~~~~

The release of RedHat/CentOS 7.3 upgraded both ``python-cffi`` and
``http-parser``, both of which are dependencies for pygit2_/libgit2_. Both
``pygit2`` and ``libgit2`` packages (which are from the EPEL repository) should
be upgraded to the most recent versions, at least to ``0.24.2``.

The below errors will show up in the master log if an incompatible
``python-pygit2`` package is installed:

.. code-block:: text

    2017-02-10 09:07:34,892 [salt.utils.gitfs ][ERROR ][11211] Import pygit2 failed: CompileError: command 'gcc' failed with exit status 1
    2017-02-10 09:07:34,907 [salt.utils.gitfs ][ERROR ][11211] gitfs is configured but could not be loaded, are pygit2 and libgit2 installed?
    2017-02-10 09:07:34,907 [salt.utils.gitfs ][CRITICAL][11211] No suitable gitfs provider module is installed.
    2017-02-10 09:07:34,912 [salt.master ][CRITICAL][11211] Master failed pre flight checks, exiting

The below errors will show up in the master log if an incompatible ``libgit2``
package is installed:

.. code-block:: text

    2017-02-15 18:04:45,211 [salt.utils.gitfs ][ERROR   ][6211] Error occurred fetching gitfs remote 'https://foo.com/bar.git': No Content-Type header in response

A restart of the ``salt-master`` daemon and gitfs cache directory clean up may
be required to allow http(s) repositories to continue to be fetched.


GitPython
---------

GitPython_ 0.3.0 or newer is required to use GitPython for gitfs. For
RHEL-based Linux distros, a compatible version is available in EPEL, and can be
easily installed on the master using yum:

.. code-block:: bash

    # yum install GitPython

Ubuntu 14.04 LTS and Debian Wheezy (7.x) also have a compatible version packaged:

.. code-block:: bash

    # apt-get install python-git

GitPython_ requires the ``git`` CLI utility to work. If installed from a system
package, then git should already be installed, but if installed via pip_ then
it may still be necessary to install git separately. For MacOS users,
GitPython_ comes bundled in with the Salt installer, but git must still be
installed for it to work properly. Git can be installed in several ways,
including by installing XCode_.

.. _pip: http://www.pip-installer.org/
.. _XCode: https://developer.apple.com/xcode/

.. warning::
    GitPython advises against the use of its library for long-running processes
    (such as a salt-master or salt-minion). Please see their warning on potential
    leaks of system resources:
    https://github.com/gitpython-developers/GitPython#leakage-of-system-resources.

.. warning::

    Keep in mind that if GitPython has been previously installed on the master
    using pip (even if it was subsequently uninstalled), then it may still
    exist in the build cache (typically ``/tmp/pip-build-root/GitPython``) if
    the cache is not cleared after installation. The package in the build cache
    will override any requirement specifiers, so if you try upgrading to
    version 0.3.2.RC1 by running ``pip install 'GitPython==0.3.2.RC1'`` then it
    will ignore this and simply install the version from the cache directory.
    Therefore, it may be necessary to delete the GitPython directory from the
    build cache in order to ensure that the specified version is installed.

.. warning::

    GitPython_ 2.0.9 and newer is not compatible with Python 2.6. If installing
    GitPython_ using pip on a machine running Python 2.6, make sure that a
    version earlier than 2.0.9 is installed. This can be done on the CLI by
    running ``pip install 'GitPython<2.0.9'``, or in a :py:func:`pip.installed
    <salt.states.pip_state.installed>` state using the following SLS:

    .. code-block:: yaml

        GitPython:
          pip.installed:
            - name: 'GitPython < 2.0.9'

Simple Configuration
====================

To use the gitfs backend, only two configuration changes are required on the
master:

1. Include ``gitfs`` in the :conf_master:`fileserver_backend` list in the
   master config file:

   .. code-block:: yaml

       fileserver_backend:
         - gitfs

   .. note::
       ``git`` also works here. Prior to the 2018.3.0 release, *only* ``git``
       would work.

2. Specify one or more ``git://``, ``https://``, ``file://``, or ``ssh://``
   URLs in :conf_master:`gitfs_remotes` to configure which repositories to
   cache and search for requested files:

   .. code-block:: yaml

       gitfs_remotes:
         - https://github.com/saltstack-formulas/salt-formula.git

   SSH remotes can also be configured using scp-like syntax:

   .. code-block:: yaml

       gitfs_remotes:
         - git@github.com:user/repo.git
         - ssh://user@domain.tld/path/to/repo.git

   Information on how to authenticate to SSH remotes can be found :ref:`here
   <gitfs-authentication>`.

3. Restart the master to load the new configuration.


.. note::

    In a master/minion setup, files from a gitfs remote are cached once by the
    master, so minions do not need direct access to the git repository.


Multiple Remotes
================

The ``gitfs_remotes`` option accepts an ordered list of git remotes to
cache and search, in listed order, for requested files.

A simple scenario illustrates this cascading lookup behavior:

If the ``gitfs_remotes`` option specifies three remotes:

.. code-block:: yaml

    gitfs_remotes:
      - git://github.com/example/first.git
      - https://github.com/example/second.git
      - file:///root/third

And each repository contains some files:

.. code-block:: yaml

    first.git:
        top.sls
        edit/vim.sls
        edit/vimrc
        nginx/init.sls

    second.git:
        edit/dev_vimrc
        haproxy/init.sls

    third:
        haproxy/haproxy.conf
        edit/dev_vimrc

Salt will attempt to lookup the requested file from each gitfs remote
repository in the order in which they are defined in the configuration. The
:strong:`git://github.com/example/first.git` remote will be searched first.
If the requested file is found, then it is served and no further searching
is executed. For example:

* A request for the file :strong:`salt://haproxy/init.sls` will be served from
  the :strong:`https://github.com/example/second.git` git repo.
* A request for the file :strong:`salt://haproxy/haproxy.conf` will be served from the
  :strong:`file:///root/third` repo.

.. note::

    This example is purposefully contrived to illustrate the behavior of the
    gitfs backend. This example should not be read as a recommended way to lay
    out files and git repos.

    The :strong:`file://` prefix denotes a git repository in a local directory.
    However, it will still use the given :strong:`file://` URL as a remote,
    rather than copying the git repo to the salt cache.  This means that any
    refs you want accessible must exist as *local* refs in the specified repo.

.. warning::

    Salt versions prior to 2014.1.0 are not tolerant of changing the
    order of remotes or modifying the URI of existing remotes. In those
    versions, when modifying remotes it is a good idea to remove the gitfs
    cache directory (``/var/cache/salt/master/gitfs``) before restarting the
    salt-master service.

.. _gitfs-per-remote-config:

Per-remote Configuration Parameters
===================================

.. versionadded:: 2014.7.0

The following master config parameters are global (that is, they apply to all
configured gitfs remotes):

* :conf_master:`gitfs_base`
* :conf_master:`gitfs_root`
* :conf_master:`gitfs_ssl_verify`
* :conf_master:`gitfs_mountpoint` (new in 2014.7.0)
* :conf_master:`gitfs_user` (**pygit2 only**, new in 2014.7.0)
* :conf_master:`gitfs_password` (**pygit2 only**, new in 2014.7.0)
* :conf_master:`gitfs_insecure_auth` (**pygit2 only**, new in 2014.7.0)
* :conf_master:`gitfs_pubkey` (**pygit2 only**, new in 2014.7.0)
* :conf_master:`gitfs_privkey` (**pygit2 only**, new in 2014.7.0)
* :conf_master:`gitfs_passphrase` (**pygit2 only**, new in 2014.7.0)
* :conf_master:`gitfs_refspecs` (new in 2017.7.0)
* :conf_master:`gitfs_disable_saltenv_mapping` (new in 2018.3.0)
* :conf_master:`gitfs_ref_types` (new in 2018.3.0)
* :conf_master:`gitfs_update_interval` (new in 2018.3.0)

.. note::
    pygit2 only supports disabling SSL verification in versions 0.23.2 and
    newer.

These parameters can now be overridden on a per-remote basis. This allows for a
tremendous amount of customization. Here's some example usage:

.. code-block:: yaml

    gitfs_provider: pygit2
    gitfs_base: develop

    gitfs_remotes:
      - https://foo.com/foo.git
      - https://foo.com/bar.git:
        - root: salt
        - mountpoint: salt://bar
        - base: salt-base
        - ssl_verify: False
        - update_interval: 120
      - https://foo.com/bar.git:
        - name: second_bar_repo
        - root: other/salt
        - mountpoint: salt://other/bar
        - base: salt-base
        - ref_types:
          - branch
      - http://foo.com/baz.git:
        - root: salt/states
        - user: joe
        - password: mysupersecretpassword
        - insecure_auth: True
        - disable_saltenv_mapping: True
        - saltenv:
          - foo:
            - ref: foo
      - http://foo.com/quux.git:
        - all_saltenvs: master

.. important::

    There are two important distinctions which should be noted for per-remote
    configuration:

    1. The URL of a remote which has per-remote configuration must be suffixed
       with a colon.

    2. Per-remote configuration parameters are named like the global versions,
       with the ``gitfs_`` removed from the beginning. The exception being the
       ``name``, ``saltenv``, and ``all_saltenvs`` parameters, which are only
       available to per-remote configurations.

    The ``all_saltenvs`` parameter is new in the 2018.3.0 release.

In the example configuration above, the following is true:

1. The first and fourth gitfs remotes will use the ``develop`` branch/tag as the
   ``base`` environment, while the second and third will use the ``salt-base``
   branch/tag as the ``base`` environment.

2. The first remote will serve all files in the repository. The second
   remote will only serve files from the ``salt`` directory (and its
   subdirectories). The third remote will only server files from the
   ``other/salt`` directory (and its subdirectories), while the fourth remote
   will only serve files from the ``salt/states`` directory (and its
   subdirectories).

3. The third remote will only serve files from branches, and not from tags or
   SHAs.

4. The fourth remote will only have two saltenvs available: ``base`` (pointed
   at ``develop``), and ``foo`` (pointed at ``foo``).

5. The first and fourth remotes will have files located under the root of the
   Salt fileserver namespace (``salt://``). The files from the second remote
   will be located under ``salt://bar``, while the files from the third remote
   will be located under ``salt://other/bar``.

6. The second and third remotes reference the same repository and unique names
   need to be declared for duplicate gitfs remotes.

7. The fourth remote overrides the default behavior of :ref:`not authenticating
   to insecure (non-HTTPS) remotes <gitfs-insecure-auth>`.

8. Because ``all_saltenvs`` is configured for the fifth remote, files from the
   branch/tag ``master`` will appear in every fileserver environment.

   .. note::
       The use of ``http://`` (instead of ``https://``) is permitted here
       *only* because authentication is not being used. Otherwise, the
       ``insecure_auth`` parameter must be used (as in the fourth remote) to
       force Salt to authenticate to an ``http://`` remote.

9. The first remote will wait 120 seconds between updates instead of 60.

.. _gitfs-per-saltenv-config:

Per-Saltenv Configuration Parameters
====================================

.. versionadded:: 2016.11.0

For more granular control, Salt allows the following three things to be
overridden for individual saltenvs within a given repo:

- The :ref:`mountpoint <gitfs-walkthrough-mountpoint>`
- The :ref:`root <gitfs-walkthrough-root>`
- The branch/tag to be used for a given saltenv

Here is an example:

.. code-block:: yaml

    gitfs_root: salt

    gitfs_saltenv:
      - dev:
        - mountpoint: salt://gitfs-dev
        - ref: develop

    gitfs_remotes:
      - https://foo.com/bar.git:
        - saltenv:
          - staging:
            - ref: qa
            - mountpoint: salt://bar-staging
          - dev:
            - ref: development
      - https://foo.com/baz.git:
        - saltenv:
          - staging:
            - mountpoint: salt://baz-staging

Given the above configuration, the following is true:

1. For all gitfs remotes, files for the ``dev`` saltenv will be located under
   ``salt://gitfs-dev``.

2. For the ``dev`` saltenv, files from the first remote will be sourced from
   the ``development`` branch, while files from the second remote will be
   sourced from the ``develop`` branch.

3. For the ``staging`` saltenv, files from the first remote will be located
   under ``salt://bar-staging``, while files from the second remote will be
   located under ``salt://baz-staging``.

4. For all gitfs remotes, and in all saltenvs, files will be served from the
   ``salt`` directory (and its subdirectories).


.. _gitfs-custom-refspecs:

Custom Refspecs
===============

.. versionadded:: 2017.7.0

GitFS will by default fetch remote branches and tags. However, sometimes it can
be useful to fetch custom refs (such as those created for `GitHub pull
requests`__). To change the refspecs GitFS fetches, use the
:conf_master:`gitfs_refspecs` config option:

.. __: https://help.github.com/en/github/collaborating-with-issues-and-pull-requests/checking-out-pull-requests-locally

.. code-block:: yaml

    gitfs_refspecs:
      - '+refs/heads/*:refs/remotes/origin/*'
      - '+refs/tags/*:refs/tags/*'
      - '+refs/pull/*/head:refs/remotes/origin/pr/*'
      - '+refs/pull/*/merge:refs/remotes/origin/merge/*'

In the above example, in addition to fetching remote branches and tags,
GitHub's custom refs for pull requests and merged pull requests will also be
fetched. These special ``head`` refs represent the head of the branch which is
requesting to be merged, and the ``merge`` refs represent the result of the
base branch after the merge.

.. important::
    When using custom refspecs, the destination of the fetched refs *must* be
    under ``refs/remotes/origin/``, preferably in a subdirectory like in the
    example above. These custom refspecs will map as environment names using
    their relative path underneath ``refs/remotes/origin/``. For example,
    assuming the configuration above, the head branch for pull request 12345
    would map to fileserver environment ``pr/12345`` (slash included).

Refspecs can be configured on a :ref:`per-remote basis
<gitfs-per-remote-config>`. For example, the below configuration would only
alter the default refspecs for the *second* GitFS remote. The first remote
would only fetch branches and tags (the default).

.. code-block:: yaml

    gitfs_remotes:
      - https://domain.tld/foo.git
      - https://domain.tld/bar.git:
        - refspecs:
          - '+refs/heads/*:refs/remotes/origin/*'
          - '+refs/tags/*:refs/tags/*'
          - '+refs/pull/*/head:refs/remotes/origin/pr/*'
          - '+refs/pull/*/merge:refs/remotes/origin/merge/*'


.. _gitfs-global-remotes:

Global Remotes
==============

.. versionadded:: 2018.3.0 for all_saltenvs, 3001 for fallback

The ``all_saltenvs`` per-remote configuration parameter overrides the logic
Salt uses to map branches/tags to fileserver environments (i.e. saltenvs). This
allows a single branch/tag to appear in *all* GitFS saltenvs.

.. note::
   ``all_saltenvs`` only works *within* GitFS. That is, files in a branch
   configured using ``all_saltenvs`` will *not* show up in a fileserver
   environment defined via some other fileserver backend (e.g.
   :conf_master:`file_roots`).

The ``fallback`` global or per-remote configuration can also be used.

This is very useful in particular when working with :ref:`salt formulas
<conventions-formula>`. Prior to the addition of this feature, it was necessary
to push a branch/tag to the remote repo for each saltenv in which that formula
was to be used. If the formula needed to be updated, this update would need to
be reflected in all of the other branches/tags. This is both inconvenient and
not scalable.

With ``all_saltenvs``, it is now possible to define your formula once, in a
single branch.

.. code-block:: yaml

    gitfs_remotes:
      - http://foo.com/quux.git:
        - all_saltenvs: anything

If you want to also test working branches of the formula repository, use
``fallback``:

.. code-block:: yaml

    gitfs_remotes:
      - http://foo.com/quux.git:
        - fallback: anything

.. _gitfs-update-intervals:

Update Intervals
================

Prior to the 2018.3.0 release, GitFS would update its fileserver backends as part
of a dedicated "maintenance" process, in which various routine maintenance
tasks were performed. This tied the update interval to the
:conf_master:`loop_interval` config option, and also forced all fileservers to
update at the same interval.

Now it is possible to make GitFS update at its own interval, using
:conf_master:`gitfs_update_interval`:

.. code-block:: yaml

    gitfs_update_interval: 180

    gitfs_remotes:
      - https://foo.com/foo.git
      - https://foo.com/bar.git:
        - update_interval: 120

Using the above configuration, the first remote would update every three
minutes, while the second remote would update every two minutes.

Configuration Order of Precedence
=================================

The order of precedence for GitFS configuration is as follows (each level
overrides all levels below it):

1. Per-saltenv configuration (defined under a per-remote ``saltenv``
   param)

   .. code-block:: yaml

       gitfs_remotes:
         - https://foo.com/bar.git:
           - saltenv:
             - dev:
               - mountpoint: salt://bar

2. Global per-saltenv configuration (defined in :conf_master:`gitfs_saltenv`)

   .. code-block:: yaml

       gitfs_saltenv:
         - dev:
           - mountpoint: salt://bar

3. Per-remote configuration parameter

   .. code-block:: yaml

       gitfs_remotes:
         - https://foo.com/bar.git:
           - mountpoint: salt://bar

4. Global configuration parameter

   .. code-block:: yaml

       gitfs_mountpoint: salt://bar

.. note::
    The one exception to the above is when :ref:`all_saltenvs
    <gitfs-global-remotes>` is used. This value overrides all logic for mapping
    branches/tags to fileserver environments. So, even if
    :conf_master:`gitfs_saltenv` is used to globally override the mapping for a
    given saltenv, :ref:`all_saltenvs <gitfs-global-remotes>` would take
    precedence for any remote which uses it.

    It's important to note however that any ``root`` and ``mountpoint`` values
    configured in :conf_master:`gitfs_saltenv` (or :ref:`per-saltenv
    configuration <gitfs-per-saltenv-config>`) would be unaffected by this.

.. _gitfs-walkthrough-root:

Serving from a Subdirectory
===========================

The :conf_master:`gitfs_root` parameter allows files to be served from a
subdirectory within the repository. This allows for only part of a repository
to be exposed to the Salt fileserver.

Assume the below layout:

.. code-block:: text

    .gitignore
    README.txt
    foo/
    foo/bar/
    foo/bar/one.txt
    foo/bar/two.txt
    foo/bar/three.txt
    foo/baz/
    foo/baz/top.sls
    foo/baz/edit/vim.sls
    foo/baz/edit/vimrc
    foo/baz/nginx/init.sls

The below configuration would serve only the files under ``foo/baz``, ignoring
the other files in the repository:

.. code-block:: yaml

    gitfs_remotes:
      - git://mydomain.com/stuff.git

    gitfs_root: foo/baz

The root can also be configured on a :ref:`per-remote basis
<gitfs-per-remote-config>`.


.. _gitfs-walkthrough-mountpoint:

Mountpoints
===========

.. versionadded:: 2014.7.0

The :conf_master:`gitfs_mountpoint` parameter will prepend the specified path
to the files served from gitfs. This allows an existing repository to be used,
rather than needing to reorganize a repository or design it around the layout
of the Salt fileserver.

Before the addition of this feature, if a file being served up via gitfs was
deeply nested within the root directory (for example,
``salt://webapps/foo/files/foo.conf``, it would be necessary to ensure that the
file was properly located in the remote repository, and that all of the
parent directories were present (for example, the directories
``webapps/foo/files/`` would need to exist at the root of the repository).

The below example would allow for a file ``foo.conf`` at the root of the
repository to be served up from the Salt fileserver path
``salt://webapps/foo/files/foo.conf``.

.. code-block:: yaml

    gitfs_remotes:
      - https://mydomain.com/stuff.git

    gitfs_mountpoint: salt://webapps/foo/files

Mountpoints can also be configured on a :ref:`per-remote basis
<gitfs-per-remote-config>`.


Using gitfs in Masterless Mode
==============================

Since 2014.7.0, gitfs can be used in masterless mode. To do so, simply add the
gitfs configuration parameters (and set :conf_master:`fileserver_backend`) in
the _minion_ config file instead of the master config file.


Using gitfs Alongside Other Backends
====================================

Sometimes it may make sense to use multiple backends; for instance, if ``sls``
files are stored in git but larger files are stored directly on the master.

The cascading lookup logic used for multiple remotes is also used with multiple
backends. If the :conf_master:`fileserver_backend` option contains multiple
backends:

.. code-block:: yaml

    fileserver_backend:
      - roots
      - git

Then the ``roots`` backend (the default backend of files in ``/srv/salt``) will
be searched first for the requested file; then, if it is not found on the
master, each configured git remote will be searched.

.. note::

    This can be used together with `file_roots` accepting `__env__` as a catch-all
    environment, since 2018.3.5 and 2019.2.1:

    .. code-block:: yaml

        file_roots:
          base:
            - /srv/salt
          __env__:
            - /srv/salt

Branches, Environments, and Top Files
=====================================

When using the GitFS backend, branches, and tags will be mapped to environments
using the branch/tag name as an identifier.

There is one exception to this rule: the ``master`` branch is implicitly mapped
to the ``base`` environment.

So, for a typical ``base``, ``qa``, ``dev`` setup, the following branches could
be used:

.. code-block:: yaml

    master
    qa
    dev

``top.sls`` files from different branches will be merged into one at runtime.
Since this can lead to overly complex configurations, the recommended setup is
to have a separate repository, containing only the ``top.sls`` file with just
one single ``master`` branch.

To map a branch other than ``master`` as the ``base`` environment, use the
:conf_master:`gitfs_base` parameter.

.. code-block:: yaml

    gitfs_base: salt-base

The base can also be configured on a :ref:`per-remote basis
<gitfs-per-remote-config>`.


.. _gitfs-whitelist-blacklist:

Environment Whitelist/Blacklist
===============================

.. versionadded:: 2014.7.0

The :conf_master:`gitfs_saltenv_whitelist` and
:conf_master:`gitfs_saltenv_blacklist` parameters allow for greater control
over which branches/tags are exposed as fileserver environments. Exact matches,
globs, and regular expressions are supported, and are evaluated in that order.
If using a regular expression, ``^`` and ``$`` must be omitted, and the
expression must match the entire branch/tag.

.. code-block:: yaml

    gitfs_saltenv_whitelist:
      - base
      - v1.*
      - 'mybranch\d+'

.. note::

    ``v1.*``, in this example, will match as both a glob and a regular
    expression (though it will have been matched as a glob, since globs are
    evaluated before regular expressions).

The behavior of the blacklist/whitelist will differ depending on which
combination of the two options is used:

* If only :conf_master:`gitfs_saltenv_whitelist` is used, then **only**
  branches/tags which match the whitelist will be available as environments

* If only :conf_master:`gitfs_saltenv_blacklist` is used, then the
  branches/tags which match the blacklist will **not** be available as
  environments

* If both are used, then the branches/tags which match the whitelist, but do
  **not** match the blacklist, will be available as environments.

.. _gitfs-authentication:

Authentication
==============

pygit2
------

.. versionadded:: 2014.7.0

Both HTTPS and SSH authentication are supported as of version 0.20.3, which is
the earliest version of pygit2_ supported by Salt for gitfs.

.. note::

    The examples below make use of per-remote configuration parameters, a
    feature new to Salt 2014.7.0. More information on these can be found
    :ref:`here <gitfs-per-remote-config>`.

HTTPS
~~~~~

For HTTPS repositories which require authentication, the username and password
can be provided like so:

.. code-block:: yaml

    gitfs_remotes:
      - https://domain.tld/myrepo.git:
        - user: git
        - password: mypassword

.. _gitfs-insecure-auth:

If the repository is served over HTTP instead of HTTPS, then Salt will by
default refuse to authenticate to it. This behavior can be overridden by adding
an ``insecure_auth`` parameter:

.. code-block:: yaml

    gitfs_remotes:
      - http://domain.tld/insecure_repo.git:
        - user: git
        - password: mypassword
        - insecure_auth: True

.. _pygit2-authentication-ssh:

SSH
~~~

SSH repositories can be configured using the ``ssh://`` protocol designation,
or using scp-like syntax. So, the following two configurations are equivalent:

* ``ssh://git@github.com/user/repo.git``
* ``git@github.com:user/repo.git``

Both :conf_master:`gitfs_pubkey` and :conf_master:`gitfs_privkey` (or their
:ref:`per-remote counterparts <gitfs-per-remote-config>`) must be configured in
order to authenticate to SSH-based repos. If the private key is protected with
a passphrase, it can be configured using :conf_master:`gitfs_passphrase` (or
simply ``passphrase`` if being configured :ref:`per-remote
<gitfs-per-remote-config>`). For example:

.. code-block:: yaml

    gitfs_remotes:
      - git@github.com:user/repo.git:
        - pubkey: /root/.ssh/id_rsa.pub
        - privkey: /root/.ssh/id_rsa
        - passphrase: myawesomepassphrase

Finally, the SSH host key must be :ref:`added to the known_hosts file
<gitfs-ssh-fingerprint>`.

.. note::
    There is a known issue with public-key SSH authentication to Microsoft
    Visual Studio (VSTS) with pygit2. This is due to a bug or lack of support
    for VSTS in older libssh2 releases. Known working releases include libssh2
    1.7.0 and later, and known incompatible releases include 1.5.0 and older.
    At the time of this writing, 1.6.0 has not been tested.

    Since upgrading libssh2 would require rebuilding many other packages (curl,
    etc.), followed by a rebuild of libgit2 and a reinstall of pygit2, an
    easier workaround for systems with older libssh2 is to use GitPython with a
    passphraseless key for authentication.

GitPython
---------

HTTPS
~~~~~

For HTTPS repositories which require authentication, the username and password
can be configured in one of two ways. The first way is to include them in the
URL using the format ``https://<user>:<password>@<url>``, like so:

.. code-block:: yaml

    gitfs_remotes:
      - https://git:mypassword@domain.tld/myrepo.git

The other way would be to configure the authentication in ``~/.netrc``:

.. code-block:: text

    machine domain.tld
    login git
    password mypassword


If the repository is served over HTTP instead of HTTPS, then Salt will by
default refuse to authenticate to it. This behavior can be overridden by adding
an ``insecure_auth`` parameter:

.. code-block:: yaml

    gitfs_remotes:
      - http://git:mypassword@domain.tld/insecure_repo.git:
        - insecure_auth: True

SSH
~~~

Only passphrase-less SSH public key authentication is supported using
GitPython. **The auth parameters (pubkey, privkey, etc.) shown in the pygit2
authentication examples above do not work with GitPython.**

.. code-block:: yaml

    gitfs_remotes:
      - ssh://git@github.com/example/salt-states.git

Since GitPython_ wraps the git CLI, the private key must be located in
``~/.ssh/id_rsa`` for the user under which the Master is running, and should
have permissions of ``0600``. Also, in the absence of a user in the repo URL,
GitPython_ will (just as SSH does) attempt to login as the current user (in
other words, the user under which the Master is running, usually ``root``).

If a key needs to be used, then ``~/.ssh/config`` can be configured to use
the desired key. Information on how to do this can be found by viewing the
manpage for ``ssh_config``. Here's an example entry which can be added to the
``~/.ssh/config`` to use an alternate key for gitfs:

.. code-block:: text

    Host github.com
        IdentityFile /root/.ssh/id_rsa_gitfs

The ``Host`` parameter should be a hostname (or hostname glob) that matches the
domain name of the git repository.

It is also necessary to :ref:`add the SSH host key to the known_hosts file
<gitfs-ssh-fingerprint>`. The exception to this would be if strict host key
checking is disabled, which can be done by adding ``StrictHostKeyChecking no``
to the entry in ``~/.ssh/config``

.. code-block:: text

    Host github.com
        IdentityFile /root/.ssh/id_rsa_gitfs
        StrictHostKeyChecking no

However, this is generally regarded as insecure, and is not recommended.

.. _gitfs-ssh-fingerprint:

Adding the SSH Host Key to the known_hosts File
-----------------------------------------------

To use SSH authentication, it is necessary to have the remote repository's SSH
host key in the ``~/.ssh/known_hosts`` file. If the master is also a minion,
this can be done using the :mod:`ssh.set_known_host
<salt.modules.ssh.set_known_host>` function:

.. code-block:: bash

    # salt mymaster ssh.set_known_host user=root hostname=github.com
    mymaster:
        ----------
        new:
            ----------
            enc:
                ssh-rsa
            fingerprint:
                16:27:ac:a5:76:28:2d:36:63:1b:56:4d:eb:df:a6:48
            hostname:
                |1|OiefWWqOD4kwO3BhoIGa0loR5AA=|BIXVtmcTbPER+68HvXmceodDcfI=
            key:
                AAAAB3NzaC1yc2EAAAABIwAAAQEAq2A7hRGmdnm9tUDbO9IDSwBK6TbQa+PXYPCPy6rbTrTtw7PHkccKrpp0yVhp5HdEIcKr6pLlVDBfOLX9QUsyCOV0wzfjIJNlGEYsdlLJizHhbn2mUjvSAHQqZETYP81eFzLQNnPHt4EVVUh7VfDESU84KezmD5QlWpXLmvU31/yMf+Se8xhHTvKSCZIFImWwoG6mbUoWf9nzpIoaSjB+weqqUUmpaaasXVal72J+UX2B+2RPW3RcT0eOzQgqlJL3RKrTJvdsjE3JEAvGq3lGHSZXy28G3skua2SmVi/w4yCE6gbODqnTWlg7+wC604ydGXA8VJiS5ap43JXiUFFAaQ==
        old:
            None
        status:
            updated

If not, then the easiest way to add the key is to su to the user (usually
``root``) under which the salt-master runs and attempt to login to the
server via SSH:

.. code-block:: text

    $ su -
    Password:
    # ssh github.com
    The authenticity of host 'github.com (192.30.252.128)' can't be established.
    RSA key fingerprint is 16:27:ac:a5:76:28:2d:36:63:1b:56:4d:eb:df:a6:48.
    Are you sure you want to continue connecting (yes/no)? yes
    Warning: Permanently added 'github.com,192.30.252.128' (RSA) to the list of known hosts.
    Permission denied (publickey).

It doesn't matter if the login was successful, as answering ``yes`` will write
the fingerprint to the known_hosts file.

Verifying the Fingerprint
~~~~~~~~~~~~~~~~~~~~~~~~~

To verify that the correct fingerprint was added, it is a good idea to look it
up. One way to do this is to use ``nmap``:

.. code-block:: bash

    $ nmap -p 22 github.com --script ssh-hostkey

    Starting Nmap 5.51 ( http://nmap.org ) at 2014-08-18 17:47 CDT
    Nmap scan report for github.com (192.30.252.129)
    Host is up (0.17s latency).
    Not shown: 996 filtered ports
    PORT     STATE SERVICE
    22/tcp   open  ssh
    | ssh-hostkey: 1024 ad:1c:08:a4:40:e3:6f:9c:f5:66:26:5d:4b:33:5d:8c (DSA)
    |_2048 16:27:ac:a5:76:28:2d:36:63:1b:56:4d:eb:df:a6:48 (RSA)
    80/tcp   open  http
    443/tcp  open  https
    9418/tcp open  git

    Nmap done: 1 IP address (1 host up) scanned in 28.78 seconds

Another way is to check one's own ``known_hosts`` file, using this one-liner:

.. code-block:: bash

    $ ssh-keygen -l -f /dev/stdin <<<`ssh-keyscan github.com 2>/dev/null` | awk '{print $2}'
    16:27:ac:a5:76:28:2d:36:63:1b:56:4d:eb:df:a6:48

.. warning::
    AWS tracks usage of nmap and may flag it as abuse. On AWS hosts, the
    ``ssh-keygen`` method is recommended for host key verification.

.. note::
    As of `OpenSSH 6.8`_ the SSH fingerprint is now shown as a base64-encoded
    SHA256 checksum of the host key. So, instead of the fingerprint looking
    like ``16:27:ac:a5:76:28:2d:36:63:1b:56:4d:eb:df:a6:48``, it would look
    like ``SHA256:nThbg6kXUpJWGl7E1IGOCspRomTxdCARLviKw6E5SY8``.

.. _`OpenSSH 6.8`: http://www.openssh.com/txt/release-6.8

Refreshing gitfs Upon Push
==========================

By default, Salt updates the remote fileserver backends every 60 seconds.
However, if it is desirable to refresh quicker than that, the :ref:`Reactor
System <reactor>` can be used to signal the master to update the fileserver on
each push, provided that the git server is also a Salt minion. There are three
steps to this process:

1. On the master, create a file **/srv/reactor/update_fileserver.sls**, with
   the following contents:

   .. code-block:: yaml

       update_fileserver:
         runner.fileserver.update

2. Add the following reactor configuration to the master config file:

   .. code-block:: yaml

       reactor:
         - 'salt/fileserver/gitfs/update':
           - /srv/reactor/update_fileserver.sls

3. On the git server, add a `post-receive hook`_

   a. If the user executing `git push` is the same as the minion user, use the following hook:

     .. code-block:: bash

         #!/usr/bin/env sh
         salt-call event.fire_master update salt/fileserver/gitfs/update

   b. To enable other git users to run the hook after a `push`, use sudo in the hook script:

     .. code-block:: bash

         #!/usr/bin/env sh
         sudo -u root salt-call event.fire_master update salt/fileserver/gitfs/update

4. If using sudo in the git hook (above), the policy must be changed to permit
   all users to fire the event.  Add the following policy to the sudoers file
   on the git server.

   .. code-block:: bash

       Cmnd_Alias SALT_GIT_HOOK = /bin/salt-call event.fire_master update salt/fileserver/gitfs/update
       Defaults!SALT_GIT_HOOK !requiretty
       ALL ALL=(root) NOPASSWD: SALT_GIT_HOOK

The ``update`` argument right after :mod:`event.fire_master
<salt.modules.event.fire_master>` in this example can really be anything, as it
represents the data being passed in the event, and the passed data is ignored
by this reactor.

Similarly, the tag name ``salt/fileserver/gitfs/update`` can be replaced by
anything, so long as the usage is consistent.

The ``root`` user name in the hook script and sudo policy should be changed to
match the user under which the minion is running.

.. _`post-receive hook`: https://www.git-scm.com/book/en/v2/Customizing-Git-Git-Hooks#Server-Side-Hooks

.. _git-as-ext_pillar:

Using Git as an External Pillar Source
======================================

The git external pillar (a.k.a. git_pillar) has been rewritten for the 2015.8.0
release. This rewrite brings with it pygit2_ support (allowing for access to
authenticated repositories), as well as more granular support for per-remote
configuration. This configuration schema is detailed :ref:`here
<git-pillar-configuration>`.

.. _faq-gitfs-bug:

Why aren't my custom modules/states/etc. syncing to my Minions?
===============================================================

In versions 0.16.3 and older, when using the :mod:`git fileserver backend
<salt.fileserver.gitfs>`, certain versions of GitPython may generate errors
when fetching, which Salt fails to catch. While not fatal to the fetch process,
these interrupt the fileserver update that takes place before custom types are
synced, and thus interrupt the sync itself. Try disabling the git fileserver
backend in the master config, restarting the master, and attempting the sync
again.

This issue is worked around in Salt 0.16.4 and newer.