page.title=Downloading the Source
@jd:body

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<div id="qv-wrapper">
  <div id="qv">
    <h2>In this document</h2>
    <ol id="auto-toc">
    </ol>
  </div>
</div>

<p>
  The Android source tree is located in a Git repository hosted by Google. This document
  describes how to download the source tree for a specific Android code-line.
</p>
<h2 id="installing-repo">
  Installing Repo
</h2>
<p>
  Repo is a tool that makes it easier to work with Git in the context of Android. For more
  information about Repo, see the <a href="developing.html">Developing</a> section.
</p>
<p>
  To install Repo:
</p>
<ol>
  <li>
    <p>
      Make sure you have a bin/ directory in your home directory and that it is included in
      your path:
    </p>
    <pre>
<code>$ mkdir ~/bin
$ PATH=~/bin:$PATH
</code>
</pre>
  </li>
  <li>
    <p>
      Download the Repo tool and ensure that it is executable:
    </p>
    <pre>
$ curl https://storage.googleapis.com/git-repo-downloads/repo &gt; ~/bin/repo
$ chmod a+x ~/bin/repo
</pre>
  </li>
</ol>
<p>
  For version 1.17, the SHA-1 checksum for repo is ddd79b6d5a7807e911b524cb223bc3544b661c28
</p>
<p>
  For version 1.19, the SHA-1 checksum for repo is 92cbad8c880f697b58ed83e348d06619f8098e6c
</p>
<p>
  For version 1.20, the SHA-1 checksum for repo is e197cb48ff4ddda4d11f23940d316e323b29671c
</p>
<p>
  For version 1.21, the SHA-1 checksum for repo is b8bd1804f432ecf1bab730949c82b93b0fc5fede
</p>
<h2 id="initializing-a-repo-client">
  Initializing a Repo client
</h2>
<p>
  After installing Repo, set up your client to access the Android source repository:
</p>
<ol>
  <li>
    <p>
      Create an empty directory to hold your working files. If you're using MacOS, this has to
      be on a case-sensitive filesystem. Give it any name you like:
    </p>
<pre>
$ mkdir WORKING_DIRECTORY
$ cd WORKING_DIRECTORY
</pre>
  </li>
  <li>
    <p>
      Run <code>repo init</code> to bring down the latest version of Repo with all its most
      recent bug fixes. You must specify a URL for the manifest, which specifies where the
      various repositories included in the Android source will be placed within your working
      directory.
    </p>
<pre>
$ repo init -u https://android.googlesource.com/platform/manifest
</pre>
    <p>
      To check out a branch other than "master", specify it with <code>-b</code>. For a list of branches, see <a href="build-numbers.html#source-code-tags-and-builds">Source Code Tags and Builds</a>.
    </p>
<pre>
$ repo init -u https://android.googlesource.com/platform/manifest -b android-4.0.1_r1
</pre>
  </li>
  <li>
    <p>
      When prompted, configure Repo with your real name and email address. To use the Gerrit
      code-review tool, you will need an email address that is connected with a <a href= 
      "https://www.google.com/accounts">registered Google account</a>. Make sure this is a live
      address at which you can receive messages. The name that you provide here will show up in
      attributions for your code submissions.
    </p>
  </li>
</ol>
<p>
  A successful initialization will end with a message stating that Repo is initialized in your
  working directory. Your client directory should now contain a <code>.repo</code> directory
  where files such as the manifest will be kept.
</p>
<h2 id="getting-the-files">
  Downloading the Android Source Tree
</h2>
<p>
  To pull down the Android source tree to your working directory from the repositories as
  specified in the default manifest, run
</p>
<pre>$ repo sync</pre>
<p>
  The Android source files will be located in your working directory under their project names.
  The initial sync operation will take an hour or more to complete. For more about <code>repo
  sync</code> and other Repo commands, see the <a href="developing.html">Developing</a> section.
</p>
<h2 id="using-authentication">
  Using Authentication
</h2>
<p>
  By default, access to the Android source code is anonymous. To protect the servers against
  excessive usage, each IP address is associated with a quota.
</p>
<p>
  When sharing an IP address with other users (e.g. when accessing the source repositories from
  beyond a NAT firewall), the quotas can trigger even for regular usage patterns (e.g. if many
  users sync new clients from the same IP address within a short period).
</p>
<p>
  In that case, it is possible to use authenticated access, which then uses a separate quota
  for each user, regardless of the IP address.
</p>
<p>
  The first step is to create a password with <a href=
  "https://android.googlesource.com/new-password">the password generator</a>
  and follow the instructions on the password generator page.
</p>
<p>
  The second step is to force authenticated access, by using the following manifest URI:
  <code>https://android.googlesource.com/a/platform/manifest</code>. Notice how the
  <code>/a/</code> directory prefix triggers mandatory authentication. You can convert an
  existing client to use mandatory authentication with the following command:
</p>
<pre>
$ repo init -u https://android.googlesource.com/a/platform/manifest
</pre>
<h2 id="troubleshooting-network-issues">
  Troubleshooting network issues
</h2>
<p>
  When downloading from behind a proxy (which is common in some corporate environments), it
  might be necessary to explicitly specify the proxy that is then used by repo:
</p>
<pre>
$ export HTTP_PROXY=http://&lt;proxy_user_id&gt;:&lt;proxy_password&gt;@&lt;proxy_server&gt;:&lt;proxy_port&gt;
$ export HTTPS_PROXY=http://&lt;proxy_user_id&gt;:&lt;proxy_password&gt;@&lt;proxy_server&gt;:&lt;proxy_port&gt;
</pre>
<p>
  More rarely, Linux clients experience connectivity issues, getting stuck in the middle of
  downloads (typically during "Receiving objects"). It has been reported that tweaking the
  settings of the TCP/IP stack and using non-parallel commands can improve the situation. You
  need root access to modify the TCP setting:
</p>
<pre>
$ sudo sysctl -w net.ipv4.tcp_window_scaling=0
$ repo sync -j1
</pre>
<h2 id="using-a-local-mirror">
  Using a local mirror
</h2>
<p>
  When using several clients, especially in situations where bandwidth is scarce, it is better
  to create a local mirror of the entire server content, and to sync clients from that mirror
  (which requires no network access). The download for a full mirror is smaller than the
  download of two clients, while containing more information.
</p>
<p>
  These instructions assume that the mirror is created in <code>/usr/local/aosp/mirror</code>.
  The first step is to create and sync the mirror itself. Notice the <code>--mirror</code> flag, which
  can be specified only when creating a new client:
</p>
<pre>
$ mkdir -p /usr/local/aosp/mirror
$ cd /usr/local/aosp/mirror
$ repo init -u https://android.googlesource.com/mirror/manifest --mirror
$ repo sync
</pre>
<p>
  Once the mirror is synced, new clients can be created from it. Note that it's important to
  specify an absolute path:
</p>
<pre>$ mkdir -p /usr/local/aosp/master
$ cd /usr/local/aosp/master
$ repo init -u /usr/local/aosp/mirror/platform/manifest.git
$ repo sync
</pre>
<p>
  Finally, to sync a client against the server, the mirror needs to be synced against the
  server, then the client against the mirror:
</p>
<pre>
$ cd /usr/local/aosp/mirror
$ repo sync
$ cd /usr/local/aosp/master
$ repo sync
</pre>
<p>
  It's possible to store the mirror on a LAN server and to access it over NFS, SSH or Git. It's
  also possible to store it on a removable drive and to pass that drive around between users or
  between machines.
</p>
<h2 id="verifying-git-tags">
  Verifying Git Tags
</h2>
<p>
  Load the following public key into your GnuPG key database. The key is used to sign annotated
  tags that represent releases.
</p>
<pre>
$ gpg --import
</pre>
<p>
  Copy and paste the key(s) below, then enter EOF (Ctrl-D) to end the input and process the
  keys.
</p>
<pre>
-----BEGIN PGP PUBLIC KEY BLOCK-----
Version: GnuPG v1.4.2.2 (GNU/Linux)
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=Wi5D
-----END PGP PUBLIC KEY BLOCK-----
</pre>
<p>
  After importing the keys, you can verify any tag with
</p>
<pre>
$ git tag -v TAG_NAME
</pre>
<p>
  If you haven't <a href="initializing.html#ccache">set up ccache</a> yet, now would be a good
  time to do it.
</p>