Contributing

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Want to contribute? Great! First, read this page.

Contributor License Agreement

Contributions to this project must be accompanied by a Contributor License Agreement. You (or your employer) retain the copyright to your contribution; this simply gives us permission to use and redistribute your contributions as part of the project. Head over to https://cla.developers.google.com/ to see your current agreements on file or to sign a new one.

You generally only need to submit a CLA once, so if you’ve already submitted one (even if it was for a different project), you probably don’t need to do it again.

Using GOPATH

Some editors may require the code to be structured in a GOPATH directory tree. In this case, you may use the :gopath target to generate a directory tree with symlinks to the original source files.

bazel build :gopath

You can then set the GOPATH in your editor to bazel-bin/gopath.

If you use this mechanism, keep in mind that the generated tree is not the canonical source. You will still need to build and test with bazel. New files will need to be added to the appropriate BUILD files, and the :gopath target will need to be re-run to generate appropriate symlinks in the GOPATH directory tree.

Dependencies can be added by using go mod get. In order to keep the WORKSPACE file in sync, run tools/go_mod.sh in place of go mod.

Coding Guidelines

All code should comply with the style guide. Note that code may be automatically formatted per the guidelines when merged.

As a secure runtime, we need to maintain the safety of all of code included in gVisor. The following rules help mitigate issues.

Definitions for the rules below:

core:

  • //pkg/sentry/...
  • Transitive dependencies in //pkg/..., etc.

runsc:

  • //runsc/...

Rules:

  • No cgo in core or runsc. The final binary must be a statically-linked pure Go binary.

  • Any files importing “unsafe” must have a name ending in _unsafe.go.

  • core may only depend on the following packages:

    • Itself.
    • Go standard library.
      • Except (transitively) package “net” (this will result in a non-cgo binary). Use //pkg/unet instead.
    • @org_golang_x_sys//unix:go_default_library (Go import golang.org/x/sys/unix).
    • Generated Go protobuf packages.
    • @com_github_golang_protobuf//proto:go_default_library (Go import github.com/golang/protobuf/proto).
    • @com_github_golang_protobuf//ptypes:go_default_library (Go import github.com/golang/protobuf/ptypes).
  • runsc may only depend on the following packages:

    • All packages allowed for core.
    • @com_github_google_subcommands//:go_default_library (Go import github.com/google/subcommands).
    • @com_github_opencontainers_runtime_spec//specs_go:go_default_library (Go import github.com/opencontainers/runtime-spec/specs_go).

Code reviews

Before sending code reviews, run bazel test ... to ensure tests are passing.

Code changes are accepted via pull request.

When approved, the change will be submitted by a team member and automatically merged into the repository.

Presubmit checks

Accessing check logs may require membership in the gvisor-dev mailing list, which is public.

Bug IDs

Some TODOs and NOTEs sprinkled throughout the code have associated IDs of the form b/1234. These correspond to bugs in our internal bug tracker. Eventually these bugs will be moved to the GitHub Issues, but until then they can simply be ignored.

Build and test with Docker

Running make dev is a convenient way to build and install runsc as a Docker runtime. The output of this command will show the runtimes installed.

You may use make refresh to refresh the binary after any changes. For example:

make dev
docker run --rm --runtime=my-branch --rm hello-world
make refresh

The small print

Contributions made by corporations are covered by a different agreement than the one above, the Software Grant and Corporate Contributor License Agreement.