Building geckodriver

geckodriver is written in [Rust], a systems programming language from Mozilla. Crucially, it relies on the [webdriver crate] to provide the HTTPD and do most of the heavy lifting of marshalling the WebDriver protocol. geckodriver translates WebDriver [commands], [responses], and [errors] to the [Marionette protocol], and acts as a proxy between [WebDriver] and [Marionette].

To build geckodriver as part of a source Firefox build, add the following to mozconfig:

ac_add_options --enable-geckodriver

With this addition geckodriver will be built when Firefox is built. It can also be built alone by passing in the source path to the `mach build` command:

% ./mach build testing/geckodriver

Artifact builds don't download geckodriver by default, but it can be built using cargo:

% cd testing/geckodriver
% cargo build
…
Compiling geckodriver v0.21.0 (file:///code/gecko/testing/geckodriver)
…
Finished dev [optimized + debuginfo] target(s) in 7.83s

Because all Rust code in central shares the same cargo workspace, the binary will be put in the $(topsrcdir)/target directory.

You can run your freshly built geckodriver this way:

% ./mach geckodriver -- --other --flags

See Testing for how to run tests.

[Rust]: https://www.rust-lang.org/ [webdriver crate]: https://crates.io/crates/webdriver [commands]: https://docs.rs/webdriver/newest/webdriver/command/ [responses]: https://docs.rs/webdriver/newest/webdriver/response/ [errors]: https://docs.rs/webdriver/newest/webdriver/error/enum.ErrorStatus.html [Marionette protocol]: /testing/marionette/Protocol.md [WebDriver]: https://w3c.github.io/webdriver/ [Marionette]: /testing/marionette/index.rst