Build/Test Tools: Check database readiness over TCP.

Merges r59484, r59489, and r63871 to the 5.9 branch.

Apply the database healthcheck changes from these revisions, retaining the client selection for older MariaDB versions. Leave their workflow and installation-script changes out of this branch.

Developed in: #13741

Props lucatume, adrianmoldovanwp, johnbillion, afercia, jorbin, desrosj.
See #66117.


git-svn-id: https://develop.svn.wordpress.org/branches/5.9@65451 602fd350-edb4-49c9-b593-d223f7449a82

Author: lancewillett

docker-compose.yml

@@ -82,8 +82,14 @@ services:
     # For compatibility with PHP versions that don't support the caching_sha2_password auth plugin used in MySQL 8.0.
     command: --default-authentication-plugin=mysql_native_password
 
+    # Ping over TCP: the client resolves the literal `localhost` to the Unix socket, which the
+    # temporary `--skip-networking` server used to initialise a cold volume answers long before
+    # the real server listens on port 3306.
     healthcheck:
-      test: [ "CMD-SHELL", "if [ \"$LOCAL_DB_TYPE\" = \"mariadb\" ]; then mariadb-admin ping -h localhost; else mysqladmin ping -h localhost; fi" ]
+      test: [
+        'CMD-SHELL',
+        'if [ "$LOCAL_DB_TYPE" = "mariadb" ]; then case "$LOCAL_DB_VERSION" in 5.5|10.0|10.1|10.2|10.3) mysqladmin ping -h 127.0.0.1 --protocol=tcp || exit $$?;; *) mariadb-admin ping -h 127.0.0.1 --protocol=tcp || exit $$?;; esac; else mysqladmin ping -h 127.0.0.1 --protocol=tcp || exit $$?; fi'
+      ]
       timeout: 5s
       interval: 5s
       retries: 10