Bug: 80444018

Clone this repo:
  1. 5211a85 Only accept certain Identifier.types by Sadaf Ebrahimi · 14 hours ago main master
  2. 2f5c890 Fix bug in matching URLs by Sadaf Ebrahimi · 2 days ago
  3. 5fc3343 Merge "Use repo to detach HEAD." into main by Treehugger Robot · 2 days ago
  4. e910e7a Use repo to detach HEAD. by Dan Albert · 2 days ago
  5. 42c45c4 Move tree finding to fileutils, convert test. by Dan Albert · 3 days ago


external updater is a tool to automatically update libraries in external/.


Check updates for a library or verify METADATA is valid:

tools/external_updater/updater.sh check ${LIBNAME}

Update a library, commit, and upload the change to Gerrit:

tools/external_updater/updater.sh update ${LIBNAME}

Update a library without committing and uploading to Gerrit:

tools/external_updater/updater.sh update --no-upload ${LIBNAME}

Update a library on top of the local changes in the current branch, commit, and upload the change to Gerrit:

tools/external_updater/updater.sh update --keep-local-changes ${LIBNAME}

Update a library without building:

tools/external_updater/updater.sh update --no-build ${LIBNAME}

LIBNAME can be the path to a library under external/, e.g. kotlinc, or python/cpython3.


To use this tool, a METADATA file must present at the root of the repository. The full definition can be found here. Or see example here

The most important part in the file is a list of urls. external_updater will go through all urls and uses the first supported url.

Git upstream

If type of a URL is set to GIT, the URL must be a git upstream (the one you can use with git clone). And the version field must be either a version tag, or SHA. The tool will find the latest version tag or sha based on it.

When upgrade, the tool will simply run git merge tag/sha.

IMPORTANT: It is suggested to set up a upstream-main branch to replicate upstream. Because most users don't have the privilege to upload changes not authored by themselves. This can be done by filing a bug to componentid:99104.


If the version is a SHA, the tool will always try to upgrade to the top of upstream. As long as there is any new change upstream, local library will be treated as stale.

Version tag

If the version is not a SHA, the tool will try to parse the version to get a numbered version. Currently the supported version format is:


version_number part can be numbers separated by . or - or _.

If you have project where this isn't working, file a bug so we can take a look.

Local changes

It is suggested to verify all local changes when upgrading. This can be done easily in Gerrit, by comparing parent2 and the patchset.

GitHub archive

If the url type is ARCHIVE, and the url is from GitHub, external_updater can upgrade a library based on GitHub releases.

If you have the choice between archives and git tags, choose tags. Because that makes it easier to manage local changes.

The tool will query GitHub to get the latest release from:


If the tag of latest release is not equal to version in METADATA file, a new version is found. The tool will download the tarball and overwrite the library with it.

If there are multiple archives in one GitHub release, the one most similar to previous (from METADATA) will be used.

After upgrade, files not present in the new tarball will be removed. But we explicitly keep files famous in Android tree. See here.

If more files need to be reserved, a post_update.sh can be created to copy these files over. See example.

Local patches

Local patches can be kept as patches/*.diff. They will be applied after upgrade. example

Email notification

There is some support to automatically check updates for all external libraries every hour, send email and change. Currently this is done by running the following script on a desktop machine.


cd /src/aosp
while true
        repo abandon tmp_auto_upgrade
        repo forall -c git checkout .
        repo forall -c git clean -xdf
        repo sync -c
        source build/envsetup.sh
        lunch aosp_arm-eng
        mmma tools/external_updater

        out/soong/host/linux-x86/bin/external_updater_notifier \
                --history ~/updater/history \
                --recipients=android_external_lib_updates@google.com \
                --generate_change \
        echo "Sleeping..."
        sleep 3600