Golang implementation of release note generating tool.

This is a duplication of the shell script "relnotes". Commits have
been squashed. Original commits can be found at
https://github.com/roycaihw/release/tree/relnotes-dev

.bazelrc

@@ -0,0 +1,5 @@
+# TODO: Remove this default once rules_go is bumped.
+# Ref kubernetes/kubernetes#52677
+build --incompatible_comprehension_variables_do_not_leak=false
+# TODO: remove the following once repo-infra is bumped.
+build --incompatible_disallow_set_constructor=false

BUILD.bazel

@@ -0,0 +1,8 @@
+load("@io_bazel_rules_go//go:def.bzl", "gazelle")
+
+gazelle(
+	name = "gazelle",
+	prefix = "k8s.io/release",
+	external = "vendored",
+)
+

WORKSPACE

@@ -1 +1,12 @@
 workspace(name = "io_kubernetes_build")
+http_archive(
+    name = "io_bazel_rules_go",
+    url = "https://github.com/bazelbuild/rules_go/releases/download/0.6.0/rules_go-0.6.0.tar.gz",
+    sha256 = "ba6feabc94a5d205013e70792accb6cce989169476668fbaf98ea9b342e13b59",
+)
+load("@io_bazel_rules_go//go:def.bzl", "go_rules_dependencies", "go_register_toolchains")
+go_rules_dependencies()
+go_register_toolchains()
+
+load("@io_bazel_rules_go//proto:def.bzl", "proto_register_toolchains")
+proto_register_toolchains()

toolbox/relnotes/BUILD.bazel

@@ -0,0 +1,27 @@
+load("@io_bazel_rules_go//go:def.bzl", "go_binary", "go_library", "go_test")
+
+go_library(
+    name = "go_default_library",
+    srcs = ["main.go"],
+    importpath = "k8s.io/release/toolbox/relnotes",
+    visibility = ["//visibility:private"],
+    deps = [
+        "//toolbox/util:go_default_library",
+        "//vendor/github.com/google/go-github/github:go_default_library",
+    ],
+)
+
+go_binary(
+    name = "relnotes",
+    importpath = "k8s.io/release/toolbox/relnotes",
+    library = ":go_default_library",
+    visibility = ["//visibility:public"],
+)
+
+go_test(
+    name = "go_default_test",
+    srcs = ["main_test.go"],
+    importpath = "k8s.io/release/toolbox/relnotes",
+    library = ":go_default_library",
+    deps = ["//toolbox/util:go_default_library"],
+)

toolbox/relnotes/README.md

@@ -0,0 +1,45 @@
+# Release Notes Collector
+
+This is a Golang implementation of existing release note collector
+[relnotes](https://github.com/kubernetes/release/blob/master/relnotes).
+
+Golang requires this repo being placed within $GOPATH, explicitly at
+$GOPATH/src/k8s.io/release.
+
+This tool also uses [dep](https://github.com/golang/dep) to manage Golang
+dependencies. To install dep, follow the instructions in [dep's Github
+page](https://github.com/golang/dep).
+
+**To bulid, run the build script:**
+
+`./build.sh`
+
+**Or do it manually:**
+
+`cd $GOPATH/src/k8s.io/release`
+
+`dep ensure`
+
+`bazel run //:gazelle`
+
+`bazel build toolbox/relnotes:relnotes`
+
+**Some example command gathering release notes for Kubernetes (assume currently in
+a kubernetes repo):**
+
+* (On branch release-1.7:)
+
+`../release/bazel-bin/toolbox/relnotes/relnotes --preview --htmlize-md
+--html-file /tmp/release-note-html-testfile
+--release-tars=_output/release-tars v1.7.0..v1.7.2`
+
+* (On branch release-1.7:)
+
+`../release/bazel-bin/toolbox/relnotes/relnotes --preview --html-file
+/tmp/release-note-html-testfile --release-tars=_output/release-tars
+v1.7.0..v1.7.0`
+
+* (On branch release-1.6.3:)
+
+`../release/bazel-bin/toolbox/relnotes/relnotes --html-file
+/tmp/release-note-html-testfile --full`

toolbox/relnotes/build.sh

@@ -0,0 +1,16 @@
+#!/bin/bash
+
+# This is a build script for Golang relnotes (release note collector), see
+# README.md for more information.
+
+# At the root directory
+cd $GOPATH/src/k8s.io/release
+
+# Run dep to get the dependencies
+dep ensure
+
+# Run gazelle to auto-generate BUILD files
+bazel run //:gazelle
+
+# Build the program
+bazel build toolbox/relnotes:relnotes