ci: move CircleCI env variables definition to shell script (#26596)

PR Close #26596

.circleci/env-helpers.inc.sh

@@ -0,0 +1,38 @@
+####################################################################################################
+# Helpers for defining environment variables for CircleCI.
+#
+# In CircleCI, each step runs in a new shell. The way to share ENV variables across steps is to
+# export them from `$BASH_ENV`, which is automatically sourced at the beginning of every step (for
+# the default `bash` shell).
+#
+# See also https://circleci.com/docs/2.0/env-vars/#using-bash_env-to-set-environment-variables.
+####################################################################################################
+
+# Set and print an environment variable.
+#
+# Use this function for setting environment variables that are public, i.e. it is OK for them to be
+# visible to anyone through the CI logs.
+#
+# Usage: `setPublicVar <name> <value>`
+function setPublicVar() {
+  setSecretVar $1 $2;
+  echo "$1=$2";
+}
+
+# Set (without printing) an environment variable.
+#
+# Use this function for setting environment variables that are secret, i.e. should not be visible to
+# everyone through the CI logs.
+#
+# Usage: `setSecretVar <name> <value>`
+function setSecretVar() {
+  # WARNING: Secrets (e.g. passwords, access tokens) should NOT be printed.
+  # (Keep original shell options to restore at the end.)
+  local -r originalShellOptions=$(set +o);
+  set +x -eu -o pipefail;
+
+  echo "export $1=\"${2:-}\";" >> $BASH_ENV;
+
+  # Restore original shell options.
+  eval "$originalShellOptions";
+}