Solr has lots of 3rd party dependencies, defined in gradle/libs.versions.toml
.
Keeping them up-to-date is crucial for a number of reasons:
-
minimizing the risk of critical CVE vulnerabilities by staying on a recent and supported version
-
avoiding "dependency hell", that can arise from falling too far behind
Read the help/dependencies.txt file for an in-depth explanation of how dependencies are managed.
In order to upgrade a dependency, you need to run through a number of steps:
-
Identify the available versions from e.g. Maven Central
-
Update the version in
gradle/libs.versions.toml
file -
Run
./gradlew resolveAndLockAll
to re-generate lockfiles. Note that this may cause a cascading effect where the locked version of other dependencies also change. -
In case of a conflict, resolve the conflict according to
help/dependencies.txt
-
Update the license and notice files of the changed dependencies. See
help/dependencies.txt
for details. -
Run
./gradlew updateLicenses
to re-generate SHA1 checksums of the new jar files. -
Once in a while, a new version of a dependency will transitively bring in brand-new dependencies. You’ll need to decide whether to keep or exclude them. See
help/dependencies.txt
for details.
To sync the version of direct and transitive dependencies across the project, we iterate in the :platform
module
over the libraries defined in gradle/libs.version.toml
and add them as constraints. Then, we use the module in
main modules like :solr:api
and :solr:core
and transitively pass down to all other modules the constraints.
If a new module does not depend on another module that already includes :platform
as a platform dependency, it should
explicitly add it to sync the versions with the rest of the project. :solr:server
is one case where this is necessary.
When it comes to security vulnerabilities that are found in direct or transitive dependencies, the recommended way to address them is to update the specific library if there is a new release that solves this issue. For both direct and transitive dependencies, we simply have to update the version as described above.
In case it is a transitive dependency that is not directly used, you can simply add it to libs.versions.toml
as you
would with any other dependency. The dependency resolution approach defined in :platform
will handle the rest.
Don’t forget to add a # @keep
note with a reference to the vulnerable version and CVE that is fixed with the explicit
definition of the library and new version. This way it is easier to keep track of unreferenced dependencies in our
libraries toml file, and we can clean them up once the libraries using the modules are updated.
A member of the Solr community operates a Github bot running Renovate, which
files Pull Requests to Solr with dependency upgrade proposals. The PRs are labeled dependencies
and do include
changes resulting from the gradle tasks resolveAndLockAll
and updateLicenses
.
Community members and committers can then review, and if manual changes are needed, help bring the PR to completion. For many dependencies, a changelog is included in the PR text, which may help guide the upgrade decision.
The scans are run on a schedule. New PRs are filed every Sunday, and only dependency versions that are at least 5 days old are suggested, to guard against bad apples. If a new major version of a dependency is available, that will get its own separate Pull Request, so you can choose.
If an upgrade is decided, simply merge (and backport) the PR. To skip an upgrade, close the PR. If a PR is left open,
it will be re-used and auto updated whenever a newer patch- or minor version gets available. Thus, one can reduce
churn from frequently-updated dependencies by delaying merge until a few weeks before a new release. One can also
choose to change to a less frequent schedule or disable the bot, by editing renovate.json
.
Please note that Solr version prior to 10.X use a versions resolution plugin that uses versions.lock
instead of
libs.version.toml
. Therefore, changes cannot be backported via cherry-pick.
While the bot runs on a GitHub repo external to the project,
the bot behavior can be tailored by editing .github/renovate.json
in this project.
See Renovatebot docs for available options.