Allow release notes for a GitHub release to be autogenerated

README.md

@@ -88,6 +88,7 @@ Fetches and creates versioned GitHub resources.
     body: path/to/body/file
     globs:
     - paths/to/files/to/upload-*.tgz
+    generate_release_notes: true
 ```
 
 To get a specific version of a release:
@@ -180,6 +181,11 @@ prepended with this string. This is useful for adding v in front of version numb
 * `globs`: *Optional.* A list of globs for files that will be uploaded alongside
   the created release.
 
+* `generate_release_notes`: *Optional.* Causes GitHub to autogenerate the release notes
+  when creating a new release, based on the commits since the last release.
+  If `body` is specified, the body will be pre-pended to the automatically generated
+  notes. Has no effect when updating an existing release. Defaults to `false`.
+
 ## Development
 
 ### Prerequisites
@@ -200,7 +206,7 @@ Run the tests with the following commands for both `alpine` and `ubuntu` images:
 
 ```sh
 docker build -t github-release-resource -f dockerfiles/alpine/Dockerfile .
-docker build -t github-release-resource -f dockerfiles/ubuntu/Dockerfile .
+docker build -t github-release-resource -f dockerfiles/ubuntu/Dockerfile --build-arg base_image=ubuntu:latest .
 ```
 
 ### Contributing

dockerfiles/ubuntu/Dockerfile

@@ -1,7 +1,7 @@
 ARG base_image
 ARG builder_image=concourse/golang-builder
 
-FROM ${builder_image} as builder
+FROM ${builder_image} AS builder
 COPY . $GOPATH/src/github.com/concourse/github-release-resource
 ENV CGO_ENABLED 0
 WORKDIR $GOPATH/src/github.com/concourse/github-release-resource

go.mod

@@ -6,7 +6,7 @@ require (
 	github.com/Masterminds/semver v1.5.0
 	github.com/cppforlife/go-semi-semantic v0.0.0-20160921010311-576b6af77ae4
 	github.com/golang/protobuf v1.5.2 // indirect
-	github.com/google/go-github/v39 v39.0.0
+	github.com/google/go-github/v39 v39.2.0
 	github.com/mitchellh/colorstring v0.0.0-20190213212951-d06e56a500db
 	github.com/nxadm/tail v1.4.5 // indirect
 	github.com/onsi/ginkgo v1.14.2

go.sum

@@ -96,6 +96,8 @@ github.com/google/go-cmp v0.5.6 h1:BKbKCqvP6I+rmFHt06ZmyQtvB8xAkWdhFyr0ZUNZcxQ=
 github.com/google/go-cmp v0.5.6/go.mod h1:v8dTdLbMG2kIc/vJvl+f65V22dbkXbowE6jgT/gNBxE=
 github.com/google/go-github/v39 v39.0.0 h1:pygGA5ySwxEez1N39GnDauD0PaWWuGgayudyZAc941s=
 github.com/google/go-github/v39 v39.0.0/go.mod h1:C1s8C5aCC9L+JXIYpJM5GYytdX52vC1bLvHEF1IhBrE=
+github.com/google/go-github/v39 v39.2.0 h1:rNNM311XtPOz5rDdsJXAp2o8F67X9FnROXTvto3aSnQ=
+github.com/google/go-github/v39 v39.2.0/go.mod h1:C1s8C5aCC9L+JXIYpJM5GYytdX52vC1bLvHEF1IhBrE=
 github.com/google/go-querystring v1.1.0 h1:AnCroh3fv4ZBgVIf1Iwtovgjaw/GiKJo8M8yD/fhyJ8=
 github.com/google/go-querystring v1.1.0/go.mod h1:Kcdr2DB4koayq7X8pmAG4sNG59So17icRSOU623lUBU=
 github.com/google/martian v2.1.0+incompatible/go.mod h1:9I4somxYTbIHy5NJKHRl3wXiIaQGbYVAs8BPL6v8lEs=

out_command.go

@@ -63,13 +63,16 @@ func (c *OutCommand) Run(sourceDir string, request OutRequest) (OutResponse, err
 		prerelease = request.Source.PreRelease
 	}
 
+	generateReleaseNotes := request.Params.GenerateReleaseNotes
+
 	release := &github.RepositoryRelease{
-		Name:            github.String(name),
-		TagName:         github.String(tag),
-		Body:            github.String(body),
-		Draft:           github.Bool(draft),
-		Prerelease:      github.Bool(prerelease),
-		TargetCommitish: github.String(targetCommitish),
+		Name:                 github.String(name),
+		TagName:              github.String(tag),
+		Body:                 github.String(body),
+		Draft:                github.Bool(draft),
+		Prerelease:           github.Bool(prerelease),
+		TargetCommitish:      github.String(targetCommitish),
+		GenerateReleaseNotes: github.Bool(generateReleaseNotes),
 	}
 
 	existingReleases, err := c.github.ListReleases()

out_command_test.go

@@ -217,6 +217,24 @@ var _ = Describe("Out Command", func() {
 				Ω(updatedRelease.TargetCommitish).Should(Equal(github.String("1z22f1")))
 			})
 		})
+
+		Context("when set to autogenerate release notes", func() {
+			BeforeEach(func() {
+				request.Params.GenerateReleaseNotes = true
+			})
+			// See https://github.com/google/go-github/issues/2444
+			It("has no effect on updating the existing release", func() {
+				_, err := command.Run(sourcesDir, request)
+				Ω(err).ShouldNot(HaveOccurred())
+
+				Ω(githubClient.UpdateReleaseCallCount()).Should(Equal(1))
+
+				updatedRelease := githubClient.UpdateReleaseArgsForCall(0)
+				Ω(*updatedRelease.Name).Should(Equal("v0.3.12"))
+				Ω(*updatedRelease.Body).Should(Equal("this is a great release"))
+				Ω(updatedRelease.GenerateReleaseNotes).Should(BeNil())
+			})
+		})
 	})
 
 	Context("when the release has not already been created", func() {
@@ -585,5 +603,37 @@ var _ = Describe("Out Command", func() {
 				Ω(*release.TagName).Should(Equal("version-0.3.12"))
 			})
 		})
+
+		Context("with generate_release_notes set to false", func() {
+			BeforeEach(func() {
+				request.Params.GenerateReleaseNotes = false
+			})
+
+			It("creates a release on GitHub without autogenerated release notes", func() {
+				_, err := command.Run(sourcesDir, request)
+				Ω(err).ShouldNot(HaveOccurred())
+
+				Ω(githubClient.CreateReleaseCallCount()).Should(Equal(1))
+				release := githubClient.CreateReleaseArgsForCall(0)
+
+				Ω(release.GenerateReleaseNotes).Should(Equal(github.Bool(false)))
+			})
+		})
+
+		Context("with generate_release_notes set to true", func() {
+			BeforeEach(func() {
+				request.Params.GenerateReleaseNotes = true
+			})
+
+			It("creates a release on GitHub with autogenerated release notes", func() {
+				_, err := command.Run(sourcesDir, request)
+				Ω(err).ShouldNot(HaveOccurred())
+
+				Ω(githubClient.CreateReleaseCallCount()).Should(Equal(1))
+				release := githubClient.CreateReleaseArgsForCall(0)
+
+				Ω(release.GenerateReleaseNotes).Should(Equal(github.Bool(true)))
+			})
+		})
 	})
 })

resources.go

@@ -71,11 +71,12 @@ type OutRequest struct {
 }
 
 type OutParams struct {
-	NamePath      string `json:"name"`
-	BodyPath      string `json:"body"`
-	TagPath       string `json:"tag"`
-	CommitishPath string `json:"commitish"`
-	TagPrefix     string `json:"tag_prefix"`
+	NamePath             string `json:"name"`
+	BodyPath             string `json:"body"`
+	TagPath              string `json:"tag"`
+	CommitishPath        string `json:"commitish"`
+	TagPrefix            string `json:"tag_prefix"`
+	GenerateReleaseNotes bool   `json:"generate_release_notes"`
 
 	Globs []string `json:"globs"`
 }