Add basic postgresql setup

config.py

@@ -0,0 +1,21 @@
+from configparser import ConfigParser
+
+
+def config(filename="database.ini", section="postgresql"):
+    # create a parser
+    parser = ConfigParser()
+    # read config file
+    parser.read(filename)
+
+    # get section, default to postgresql
+    db = {}
+    if parser.has_section(section):
+        params = parser.items(section)
+        for param in params:
+            db[param[0]] = param[1]
+    else:
+        raise Exception(
+            "Section {0} not found in the {1} file".format(section, filename)
+        )
+
+    return db

database.ini

@@ -0,0 +1,4 @@
+# For local users you can simply rely on the UNIX permissions.
+# For remote databases you have to add host, user and password
+[postgresql]
+database=imported_git

db.py

@@ -0,0 +1,80 @@
+import psycopg2
+from config import config
+
+
+class DB:
+    def __init__(self):
+        self.connect()
+
+    def connect(self):
+        try:
+            # read the connection parameters
+            params = config()
+            # connect to the PostgreSQL server
+            self.conn = psycopg2.connect(**params)
+
+        except (Exception, psycopg2.DatabaseError) as error:
+            print(error)
+            raise error
+
+    def schema_version(self):
+        # create a cursor
+        cur = self.conn.cursor()
+
+        # execute a statement
+        try:
+            cur.execute("SELECT MAX(version) from scheme")
+        except psycopg2.errors.UndefinedTable as error:
+            cur.close()
+            self.close()
+            self.connect()
+            return 0
+
+        db_version = cur.fetchone()
+
+        cur.close()
+        return db_version[0]
+
+    def close(self):
+        if self.conn is not None:
+            self.conn.close()
+        self.conn = None
+
+    def create_tables(self):
+        """Create the tables if not existing - assumes connected"""
+
+        commands = (
+            """
+        CREATE TABLE scheme (
+            id SERIAL PRIMARY KEY,
+            version SMALLINT NOT NULL
+        )
+        """,
+            "INSERT INTO scheme (version) VALUES(1)",
+            """ CREATE TABLE revisions (
+                id SERIAL PRIMARY KEY,
+                package VARCHAR(255) NOT NULL
+                )
+        """,
+        )
+
+        if self.schema_version() > 0:
+            return
+        try:
+            cur = self.conn.cursor()
+            # create table one by one
+            for command in commands:
+                cur.execute(command)
+            # close communication with the PostgreSQL database server
+            cur.close()
+            # commit the changes
+            self.conn.commit()
+        except (Exception, psycopg2.DatabaseError) as error:
+            print(error)
+            self.close()
+            raise error
+
+
+if __name__ == "__main__":
+    db = DB()
+    db.create_tables()