Rollup merge of #66569 - pietroalbini:gha-1, r=alexcrichton

GitHub Actions: preparations, part 1

This PR adds the first batch of commits in preparation for GitHub Actions:

* Added GitHub Actions support in `src/ci/shared.sh` and bootstrap.
* Addded a `setup-environment.sh` script which guesses and sets the `DEPLOY`, `DEPLOY_ALT` and `IMAGE` environment variables automatically, to reduce the verbosity of the CI configuration.

This PR does **not** yet add any builders on GitHub Actions.

r? @alexcrichton

1 files changed, 31 insertions, 0 deletions

diff --git a/src/ci/scripts/setup-environment.sh b/src/ci/scripts/setup-environment.sh
new file mode 100755
index 00000000000..e126a06edab
--- /dev/null
+++ b/src/ci/scripts/setup-environment.sh
@@ -0,0 +1,31 @@
+#!/bin/bash
+# This script guesses some environment variables based on the builder name and
+# the current platform, to reduce the amount of variables defined in the CI
+# configuration.
+
+set -euo pipefail
+IFS=$'\n\t'
+
+source "$(cd "$(dirname "$0")" && pwd)/../shared.sh"
+
+# Builders starting with `dist-` are dist builders, but if they also end with
+# `-alt` they are alternate dist builders.
+if [[ "${CI_JOB_NAME}" = dist-* ]]; then
+    if [[ "${CI_JOB_NAME}" = *-alt ]]; then
+        echo "alternate dist builder detected, setting DEPLOY_ALT=1"
+        ciCommandSetEnv DEPLOY_ALT 1
+    else
+        echo "normal dist builder detected, setting DEPLOY=1"
+        ciCommandSetEnv DEPLOY 1
+    fi
+fi
+
+# All the Linux builds happen inside Docker.
+if isLinux; then
+    if [[ -z "${IMAGE+x}" ]]; then
+        echo "linux builder detected, using docker to run the build"
+        ciCommandSetEnv IMAGE "${CI_JOB_NAME}"
+    else
+        echo "a custom docker image is already set"
+    fi
+fi