Added a buildkite detector for detecting the correct env vars in CI (#7933)

* Added a buildkite detector for detecting the correct env vars in CI

* adding pending changelog entry

* fixed PR logic to actually match the Buildkite Docs and simplified if statement, Fixed a few typos in comments and added PR to CHANGELOG_PENDING.md

* made PR number fetch easier to read

* fixing typo in comment

CHANGELOG_PENDING.md

@@ -1,4 +1,5 @@
 ### Improvements
+* Adds CI detector for Buildkite [#7933](https://github.com/pulumi/pulumi/pull/7933)
 
 - [CLI] Adding the ability to use `pulumi org set [name]` to set a default org
   to use when creating a stacks in the Pulumi Service backend or Self -hosted Service

sdk/go/common/util/ciutil/buildkite.go

@@ -0,0 +1,56 @@
+// Copyright 2016-2021, Pulumi Corporation.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package ciutil
+
+import (
+	"os"
+)
+
+// buildkiteCI represents a Buildkite CI/CD system.
+type buildkiteCI struct {
+	baseCI
+}
+
+// DetectVars detects the env vars for a Buildkite Build.
+func (bci buildkiteCI) DetectVars() Vars {
+	v := Vars{Name: Buildkite}
+	// https://buildkite.com/docs/pipelines/environment-variables#bk-env-vars-buildkite-branch
+	v.BranchName = os.Getenv("BUILDKITE_BRANCH")
+	// https://buildkite.com/docs/pipelines/environment-variables#bk-env-vars-buildkite-build-id
+	v.BuildID = os.Getenv("BUILDKITE_BUILD_ID")
+	// https://buildkite.com/docs/pipelines/environment-variables#bk-env-vars-buildkite-build-number
+	v.BuildNumber = os.Getenv("BUILDKITE_BUILD_NUMBER")
+	// https://buildkite.com/docs/pipelines/environment-variables#bk-env-vars-buildkite-build-url
+	v.BuildURL = os.Getenv("BUILDKITE_BUILD_URL")
+	// https://buildkite.com/docs/pipelines/environment-variables#bk-env-vars-buildkite-message
+	// This is usually the commit message but can be other messages.
+	v.CommitMessage = os.Getenv("BUILDKITE_MESSAGE")
+	// https://buildkite.com/docs/pipelines/environment-variables#bk-env-vars-buildkite-pull-request
+	// If Buildkite's PR env var it is a pull request of the supplied number, else the build type is
+	// whatever Buildkite says it is. Pull requests are webhooks just like a standard push so this allows
+	// us to differentiate the two.
+	prNumber := os.Getenv("BUILDKITE_PULL_REQUEST")
+	if prNumber != "false" {
+		v.PRNumber = prNumber
+		v.BuildType = "PullRequest"
+	} else {
+		// https://buildkite.com/docs/pipelines/environment-variables#bk-env-vars-buildkite-source
+		v.BuildType = os.Getenv("BUILDKITE_SOURCE")
+	}
+	// https://buildkite.com/docs/pipelines/environment-variables#bk-env-vars-buildkite-commit
+	v.SHA = os.Getenv("BUILDKITE_COMMIT")
+
+	return v
+}

sdk/go/common/util/ciutil/detect.go

@@ -48,9 +48,11 @@ var detectors = map[SystemName]system{
 			EnvVarsToDetect: []string{"TF_BUILD"},
 		},
 	},
-	Buildkite: baseCI{
-		Name:            Buildkite,
-		EnvVarsToDetect: []string{"BUILDKITE"},
+	Buildkite: buildkiteCI{
+		baseCI: baseCI{
+			Name:            Buildkite,
+			EnvVarsToDetect: []string{"BUILDKITE"},
+		},
 	},
 	CircleCI: circleCICI{
 		baseCI: baseCI{

sdk/go/common/util/ciutil/vars_test.go

@@ -35,6 +35,13 @@ func TestDetectVars(t *testing.T) {
 			"BUILD_BUILDID":  buildNumber,
 			"GITHUB_ACTIONS": "",
 		},
+		Buildkite: {
+			"GITHUB_ACTIONS":         "",
+			"TRAVIS":                 "",
+			"BUILDKITE":              "true",
+			"BUILDKITE_BUILD_NUMBER": buildNumber,
+			"BUILDKITE_BUILD_ID":     buildID,
+		},
 		CircleCI: {
 			"TRAVIS":           "",
 			"CIRCLECI":         "true",