Add support for PostgreSQL as store engine

go.mod

@@ -61,6 +61,7 @@ require (
 	github.com/klauspost/compress v1.17.11 // indirect
 	github.com/klauspost/cpuid/v2 v2.2.9 // indirect
 	github.com/leodido/go-urn v1.4.0 // indirect
+	github.com/lib/pq v1.10.9
 	github.com/mattn/go-colorable v0.1.14 // indirect
 	github.com/mattn/go-isatty v0.0.20 // indirect
 	github.com/mattn/go-runewidth v0.0.16 // indirect

go.sum

@@ -179,6 +179,8 @@ github.com/kylelemons/godebug v1.1.0 h1:RPNrshWIDI6G2gRW9EHilWtl7Z6Sb1BR0xunSBf0
 github.com/kylelemons/godebug v1.1.0/go.mod h1:9/0rRGxNHcop5bhtWyNeEfOS8JIWk580+fNqagV/RAw=
 github.com/leodido/go-urn v1.4.0 h1:WT9HwE9SGECu3lg4d/dIA+jxlljEa1/ffXKmRjqdmIQ=
 github.com/leodido/go-urn v1.4.0/go.mod h1:bvxc+MVxLKB4z00jd1z+Dvzr47oO32F/QSNjSBOlFxI=
+github.com/lib/pq v1.10.9 h1:YXG7RB+JIjhP29X+OtkiDnYaXQwpS4JEWq7dtCCRUEw=
+github.com/lib/pq v1.10.9/go.mod h1:AlVN5x4E4T544tWzH6hKfbfQvm3HdbOxrmggDNAPY9o=
 github.com/mattn/go-colorable v0.0.9/go.mod h1:9vuHe8Xs5qXnSaW/c/ABM9alt+Vo+STaOChaDxuIBZU=
 github.com/mattn/go-colorable v0.1.4/go.mod h1:U0ppj6V5qS13XJ6of8GYAs25YV2eR4EVcfRqFIhoBtE=
 github.com/mattn/go-colorable v0.1.6/go.mod h1:u6P/XSegPjTcexA+o6vUJrdnUu04hMope9wVRipJSqc=

scripts/docker/docker-compose.yml

@@ -76,3 +76,15 @@ services:
     ports:
       - "8500:8500"
     command: "agent -dev -client=0.0.0.0"
+
+  postgres0:
+    build: ./pg-dockerfile
+    container_name: postgres0
+    environment:
+      POSTGRES_USER: postgres
+      POSTGRES_PASSWORD: postgres
+      POSTGRES_DB: testdb
+    ports:
+      - "5432:5432"
+    volumes:
+      - ./pg-init-scripts:/docker-entrypoint-initdb.d

scripts/docker/pg-dockerfile/Dockerfile

@@ -0,0 +1,33 @@
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License.  You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+# KIND, either express or implied.  See the License for the
+# specific language governing permissions and limitations
+# under the License.
+#
+FROM postgres:16
+
+RUN apt-get update && apt-get install -y \
+    postgresql-server-dev-16 \
+    build-essential \
+    libpq-dev \
+    wget
+
+RUN wget https://github.com/citusdata/pg_cron/archive/refs/tags/v1.6.5.tar.gz \
+    && tar -xvzf v1.6.5.tar.gz \
+    && cd pg_cron-1.6.5 \
+    && make && make install \
+    && cd .. && rm -rf v1.6.5.tar.gz pg_cron-1.6.5
+
+RUN echo "shared_preload_libraries = 'pg_cron'" >> /usr/share/postgresql/postgresql.conf.sample \
+    && echo "cron.database_name = 'testdb'" >> /usr/share/postgresql/postgresql.conf.sample

scripts/docker/pg-init-scripts/init.sql

@@ -0,0 +1,52 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ *
+ */
+
+CREATE TABLE locks (
+    name TEXT PRIMARY KEY,
+    leaderID TEXT NOT NULL
+);
+
+CREATE TABLE kv (
+    key TEXT PRIMARY KEY,
+    value BYTEA
+);
+
+CREATE OR REPLACE FUNCTION notify_changes()
+RETURNS TRIGGER AS $$
+BEGIN
+    IF TG_OP = 'INSERT' THEN
+        PERFORM cron.schedule('delete_' || NEW.name, '6 seconds', FORMAT('DELETE FROM locks WHERE name = %L', NEW.name));
+        PERFORM pg_notify('lock_change', 'INSERT:' || NEW.leaderID::text);
+    END IF;
+
+    IF TG_OP = 'DELETE' THEN
+        PERFORM cron.unschedule('delete_' || OLD.name);
+        PERFORM pg_notify('lock_change', 'DELETE:' || OLD.leaderID::text);
+    END IF;
+
+    RETURN NULL;
+END;
+$$ LANGUAGE plpgsql;
+
+CREATE TRIGGER lock_change_trigger
+AFTER INSERT OR DELETE ON locks
+FOR EACH ROW EXECUTE FUNCTION notify_changes();
+
+CREATE EXTENSION IF NOT EXISTS pg_cron;