Support git shallow clones and additional ref fetches

api/openapi-spec/swagger.json

@@ -258,6 +258,18 @@
  "repo"
  ],
  "properties": {
+ "depth": {
+ "description": "Depth specifies clones/fetches should be shallow and include the given number of commits from the branch tip",
+ "type": "integer",
+ "format": "int32"
+ },
+ "fetch": {
+ "description": "Fetch specifies a number of refs that should be fetched before checkout",
+ "type": "array",
+ "items": {
+ "type": "string"
+ }
+ },
  "insecureIgnoreHostKey": {
  "description": "InsecureIgnoreHostKey disables SSH strict host key checking during git clone",
  "type": "boolean"

examples/input-artifact-git.yaml

@@ -36,6 +36,17 @@ spec:
  # providers (github, bitbucket, gitlab, azure) as these keys are already baked into
  # the executor image which performs the clone.
  # insecureIgnoreHostKey: true
+ #
+ # Shallow clones/fetches can be performed by providing a `depth`.
+ # depth: 1
+ #
+ # Additional ref specs to fetch down prior to checkout can be
+ # provided with `fetch`. This may be necessary if `revision` is a
+ # non-branch/-tag ref and thus not covered by git's default fetch.
+ # See https://git-scm.com/book/en/v2/Git-Internals-The-Refspec for
+ # the refspec format.
+ # fetch: refs/meta/*
+ # fetch: refs/changes/*
  container:
  image: golang:1.10
  command: [sh, -c]

pkg/apis/workflow/v1alpha1/types.go

@@ -696,6 +696,13 @@ type GitArtifact struct {
  // Revision is the git commit, tag, branch to checkout
  Revision string `json:"revision,omitempty"`
 
+ // Depth specifies clones/fetches should be shallow and include the given
+ // number of commits from the branch tip
+ Depth *uint `json:"depth,omitempty"`
+
+ // Fetch specifies a number of refs that should be fetched before checkout
+ Fetch []string `json:"fetch,omitempty"`
+
  // UsernameSecret is the secret selector to the repository username
  UsernameSecret *apiv1.SecretKeySelector `json:"usernameSecret,omitempty"`
 

workflow/artifacts/git/git.go

@@ -11,6 +11,7 @@ import (
  log "github.com/sirupsen/logrus"
  "golang.org/x/crypto/ssh"
  git "gopkg.in/src-d/go-git.v4"
+ "gopkg.in/src-d/go-git.v4/config"
  "gopkg.in/src-d/go-git.v4/plumbing/transport"
  "gopkg.in/src-d/go-git.v4/plumbing/transport/http"
  ssh2 "gopkg.in/src-d/go-git.v4/plumbing/transport/ssh"
@@ -86,10 +87,39 @@ func gitClone(path string, inputArtifact *wfv1.Artifact, auth transport.AuthMeth
  RecurseSubmodules: git.DefaultSubmoduleRecursionDepth,
  Auth: auth,
  }
- _, err := git.PlainClone(path, false, &cloneOptions)
+ if inputArtifact.Git.Depth != nil {
+ cloneOptions.Depth = int(*inputArtifact.Git.Depth)
+ }
+
+ repo, err := git.PlainClone(path, false, &cloneOptions)
  if err != nil {
  return errors.InternalWrapError(err)
  }
+
+ if inputArtifact.Git.Fetch != nil {
+ refSpecs := make([]config.RefSpec, len(inputArtifact.Git.Fetch))
+ for i, spec := range inputArtifact.Git.Fetch {
+ refSpecs[i] = config.RefSpec(spec)
+ }
+
+ fetchOptions := git.FetchOptions{
+ RefSpecs: refSpecs,
+ }
+ if inputArtifact.Git.Depth != nil {
+ fetchOptions.Depth = int(*inputArtifact.Git.Depth)
+ }
+
+ err = fetchOptions.Validate()
+ if err != nil {
+ return errors.InternalWrapError(err)
+ }
+
+ err = repo.Fetch(&fetchOptions)
+ if err != nil {
+ return errors.InternalWrapError(err)
+ }
+ }
+
  if inputArtifact.Git.Revision != "" {
  // We still rely on forking git for checkout, since go-git does not have a reliable
  // way of resolving revisions (e.g. mybranch, HEAD^, v1.2.3)