Table of Contents (3.3.22)

# Simple Setups

Consider the following simple scenario where we will be serving Bazaar branches that live on a single server. Those branches are in the subdirectories of `/srv/bzr` (or `C:\bzr`) and they will all be related to a single project called “ProjectX”. ProjectX will have a trunk branch and at least one feature branch. As we get further, we will consider other scenarios, but this will be a sufficiently motivating example.

## Smart server

The simplest possible setup for providing outside access to the branches on the server uses Bazaar’s built-in smart server tunneled over SSH so that people who can access your server using SSH can have read and write access to branches on the server. This setup uses the authentication mechanisms of SSH including private keys, and the access control mechanisms of the server’s operating system. In particular, using groups on the server, it is possible to provide different access privileges to different groups of developers.

### Setup

There is no setup required for this on the server, apart from having Bazaar installed and SSH access available to your developers. Using SSH configuration options it is possible to restrict developers from using anything but Bazaar on the server via SSH, and to limit what part of the file system they can access.

### Client

Clients can access the branches using URLs with the `bzr+ssh://` prefix. For example, to get a local copy of the ProjectX trunk, a developer could do:

    $ brz branch bzr+ssh://server.example.com/srv/bzr/projectx/trunk projectx

If the developers have write access to the `/srv/bzr/projectx` directory, then they can create new branches themselves using:

    $ brz branch bzr+ssh://server.example.com/srv/bzr/projectx/trunk \
    bzr+ssh://server.example.com/srv/bzr/projectx/feature-gui

Of course, if this isn’t desired, then developers should not have write access to the `/srv/bzr/projectx` directory.

### Further Configuration

For a project with multiple branches that are all related, it is best to use a shared repository to hold all of the branches. To set this up, do:

    $ cd /srv/bzr
    $ brz init-shared-repo --no-trees projectx

The `--no-trees` option saves space by not creating a copy of the working files on the server’s filesystem. Then, any branch created under `/srv/bzr/projectx` (see Migration for some ways to do this) will share storage space, which is particularly helpful for branches that have many revisions in common, such as a project trunk and its feature branches.

If Bazaar or Breezy is not installed on the user’s path or not specified in the SSH configuration, then a path can be specified from the client with the `BZR_REMOTE_PATH` environment variable. For example, if the Bazaar executable is installed in `/usr/local/bzr-2.0/bin/bzr`, then a developer could use:

    $ brz_REMOTE_PATH=/usr/local/bzr-2.0/bin/bzr bzr info \
    bzr+ssh://server.example.com/srv/bzr/proectx/trunk

to get information about the trunk branch. The remote path can also be specified in Bazaar’s configuration files for a particular location. See `brz help configuration` for more details.

If developers have home directories on the server, they can use `/~/` in URLs to refer to their home directory. They can also use `/~username/` to refer to the home directory of user `username`. For example, if there are two developers `alice` and `bob`, then Bob could use:

    $ brz log bzr+ssh://server.example.com/~/fix-1023

to refer to one of his bug fix branches and:

    $ brz log bzr+ssh://server.example.com/~alice/fix-2047

to refer to one of Alice’s branches. [1]

[1]

The version of Bazaar installed on the server must be at least 2.1.0b1 or newer to support `/~/` in bzr+ssh URLs.

### Using a restricted SSH account to host multiple users and repositories

Once you have a bzr+ssh setup using a shared repository you may want to share that repository among a small set of developers. Using shared SSH access enables you to complete this task without any complicated setup or ongoing management.

To allow multiple users to access Bazaar over ssh we can allow ssh access to a common account that only allows users to run a specific command. Using a single account simplifies deployment as no permissions management issues exist for the filesystem. All users are the same user at the server level. Bazaar labels the commits with each users details so seperate server accounts are not required.

To enable this configuration we update the `~/.ssh/authorized_keys` to include command restrictions for connecting users.

In these examples the user will be called `bzruser`.

The following example shows how a single line is configured:

    command="brz serve --inet --allow-writes --directory=/srv/bzr",no-agent-forwarding,no-port-forwarding,no-pty,no-user-rc,no-X11-forwarding ssh-rsa AAA...= my bzr key

This command allows the user to access only brz and disables other SSH use. Write access to each repository in the directory `/srv/bzr` has been granted with `--allow-writes` and can be removed for individual users that should only require read access. The root of the directory structure can be altered for each user to allow them to see only a subet of the repositories available. The example below assumes two seperate repositories for Alice and Bob. This method will not allow you to restrict access to part of a repository, you may only restrict access to a single part of the directory structure:

    command="brz serve --inet --allow-writes --directory=/srv/bzr/alice/",no-agent-forwarding,no-port-forwarding,no-pty,no-user-rc,no-X11-forwarding ssh-rsa AAA...= Alice's SSH Key
    command="brz serve --inet --allow-writes --directory=/srv/bzr/bob/",no-agent-forwarding,no-port-forwarding,no-pty,no-user-rc,no-X11-forwarding ssh-rsa AAA...= Bob's SSH Key
    command="brz serve --inet --allow-writes --directory=/srv/bzr/",no-agent-forwarding,no-port-forwarding,no-pty,no-user-rc,no-X11-forwarding ssh-rsa AAA...= Repo Manager SSH Key

Alice and Bob have access to their own repository and Repo Manager has access to the each of their repositories. Users are not allowed access to any part of the system except the directory specified. The bzr+ssh urls are simplified by serving using `brz serve` and the `--directory` option.

If Alice logs in she uses the following command for her fix-1023 branch:

    $ brz log bzr+ssh://bzruser@server.example.com/fix-1023

If Repo Manager logs in he uses the following command to access Alice’s fix-1023:

    $ brz log bzr+ssh://bzruser@server.example.com/alice/fix-1023