fix(db): mechanism for db provisioning/migrations

Author: Will

docker-compose.yml

@@ -5,14 +5,17 @@ services:
     networks:
       - devnet
     volumes:
-      - "psqldata:/var/lib/postgresql/data"
-      - "./scripts/postgres_init.sql:/docker-entrypoint-initdb.d/postgres_init.sql"
+      - psqldata:/var/lib/postgresql/data
+      - ./scripts/postgres_init.sql:/docker-entrypoint-initdb.d/postgres_init.sql:ro
+      - ./scripts/postgres_always.sh:/postgres_always.sh:ro
+      - ./scripts/postgres_run.sh:/usr/local/bin/postgres_run.sh:ro
     restart: unless-stopped
     healthcheck:
-        test: ["CMD-SHELL", "psql -U fence_user -d fence_db -c 'SELECT 1;'"]
-        interval: 60s
-        timeout: 5s
-        retries: 3
+      test: ["CMD-SHELL", "psql -U fence_user -d fence_db -c 'SELECT 1;'"]
+      interval: 60s
+      timeout: 5s
+      retries: 3
+    command: postgres_run.sh
     environment:
       - POSTGRES_PASSWORD=postgres
     #

scripts/postgres_always.sh

@@ -0,0 +1,28 @@
+#!/usr/bin/env bash
+
+create_db_idempotent() {
+  # Creating a DB similar to the "IF NOT EXISTS" syntax is a bit challenging in
+  # Postgres.
+  psql -U postgres -tc "SELECT 1 FROM pg_database WHERE datname = '${1}'" | grep -q 1 || \
+  psql -U postgres -c "CREATE DATABASE ${1}"
+}
+
+create_user_idempotent() {
+  psql -U postgres << EOF
+DO \$\$
+BEGIN
+  IF NOT EXISTS(SELECT 1 FROM pg_roles WHERE rolname='${1}') THEN
+    CREATE USER ${1};
+  END IF;
+END
+\$\$;
+EOF
+}
+
+create_db_idempotent "metadata"
+create_user_idempotent "metadata_user"
+
+psql -U postgres <<EOF
+ALTER USER metadata_user WITH PASSWORD 'metadata_pass';
+ALTER USER metadata_user WITH SUPERUSER;
+EOF

scripts/postgres_run.sh

@@ -0,0 +1,33 @@
+#!/usr/bin/env bash
+
+# Thing shim around the normal Docker postgres entrypoint that allows us to run
+# non-application migrations. Things like DB and user creations that would be
+# done by cloud-automation tasks in a normal env.
+
+set -e
+
+# Initialize the DB, but don't allow outside connections yet.
+docker-entrypoint.sh postgres -c listen_addresses='127.0.0.1' &
+# Wait until the server is out of initialization mode and online.
+while ! psql -U postgres -h localhost -c 'SELECT 1;' 2>/dev/null; do sleep 1; done
+# Stop the server.
+gosu postgres pg_ctl stop
+
+echo "[postgres] run migrations"
+
+# Run migrations/scripts that should run on every start. This is handy for data
+# we want to backfill or otherwise migrate for users.
+gosu postgres bash -c "(
+  source /usr/local/bin/docker-entrypoint.sh
+  docker_setup_env
+  docker_temp_server_start
+
+  bash /postgres_always.sh
+
+  docker_temp_server_stop
+)"
+
+echo "[postgres] migrations complete"
+
+# Start postgres "normally" allowing all network clients to connect.
+docker-entrypoint.sh postgres