Add scripting for updating the Homebrew formula. (pulumi#3291)

This script will run during OS X legs, and will open a PR to update the
Homebrew formula for Pulumi on each new release.

Author: pgavlin

.travis.yml

@@ -27,6 +27,7 @@ before_script:
 - "${PULUMI_SCRIPTS}/ci/ensure-dependencies"
 script:
 - make travis_${TRAVIS_EVENT_TYPE}
+- if [ "$TRAVIS_OS_NAME" = "osx" ]; then ./scripts/update_homebrew.sh; fi
 after_failure:
 - "${PULUMI_SCRIPTS}/ci/upload-failed-tests"
 notifications:

scripts/update_homebrew.sh

@@ -0,0 +1,29 @@
+#!/bin/bash
+# update_homebrew.sh uses `brew bump-formula-pr` to update the formula for the Pulumi CLI and SDKs
+set -o nounset
+set -o errexit
+set -o pipefail
+readonly ROOT=$(dirname "${0}")/..
+
+if [[ "${TRAVIS:-}" != "true" ]]; then
+    echo "error: this script should be run from within Travis"
+    exit 1
+fi
+
+if [[ -z "${PULUMI_BOT_GITHUB_API_TOKEN:-}" ]]; then
+    echo "error: PULUMI_BOT_GITHUB_API_TOKEN must be set"
+    exit 1
+fi
+
+if ! echo "${TRAVIS_TAG:-}" | grep -q -e "^v[0-9]\+\.[0-9]\+\.[0-9]\+$"; then
+    echo "Skipping Homebrew formula update; ${TRAVIS_TAG:-} does not denote a released version"
+    exit 0
+fi
+
+if [[ "${TRAVIS_OS_NAME:-}" != "osx" ]]; then
+    echo "Skipping Homebrew formula updte; not running on OS X"
+    exit 0
+fi
+
+HOMEBREW_GITHUB_API_TOKEN="${PULUMI_BOT_GITHUB_API_TOKEN:-}" brew bump-formula-pr --tag="${TRAVIS_TAG:-}" --revision="${TRAVIS_COMMIT:-}" pulumi
+exit 0