recipe/postgres: Delete stale postmaster.pid when run the service

If there has a stale postmaster.pid, it will be an error if we are
trying to connect the server. In this case, delete it and then start the
service again.

slapos/recipe/postgres.py

@@ -194,6 +194,28 @@ class Recipe(GenericBaseRecipe):
     def createDatabase(self):
         self.runPostgresCommand(cmd='CREATE DATABASE "%s"' % self.options['dbname'])
 
+    def isPosgresServerRunning(self):
+        pgdata = self.options['pgdata-directory']
+        postmaster_pid_file = os.path.join(pgdata, 'postmaster.pid')
+        if os.path.exists(postmaster_pid_file):
+            pg_ctl_binary = os.path.join(self.options['bin'], 'pg_ctl')
+            self.check_exists(pg_ctl_binary)
+
+            # Check the postgres is running or not
+            # if not, delete the ppostmaster.pid and run it again
+            try:
+              output1 = subprocess.check_output([pg_ctl_binary, 'status', '-D', pgdata], stderr=subprocess.STDOUT)
+            except subprocess.CalledProcessError as e:
+              if e.returncode == 3:
+                # If the server is not running, pg_ctl returns an exit status of 3
+                # see https://www.postgresql.org/docs/current/app-pg-ctl.html
+                os.remove(postmaster_pid_file)
+                return False
+              else:
+                raise
+            return True
+        else:
+          return False
 
     def updateSuperuser(self):
         """\
@@ -211,7 +233,7 @@ class Recipe(GenericBaseRecipe):
         change_password_query = """ALTER USER "%s" ENCRYPTED PASSWORD '%s'""" % (user, enc_password)
 
         pgdata = self.options['pgdata-directory']
-        if os.path.exists(os.path.join(pgdata, 'postmaster.pid')):
+        if self.isPosgresServerRunning():
             psql_binary = os.path.join(self.options['bin'], 'psql')
             # connect to a running postgres deamon
             p = subprocess.Popen([

slapos/test/recipe/test_postgres.py

@@ -90,6 +90,26 @@ class PostgresTest(unittest.TestCase):
         self.assertEqual(cursor.fetchone(), (2,))
     cnx.close()
 
+  def test_stale_pid_file_does_not_prevent_install(self):
+    self.recipe.install()
+
+    # Malformed postmaster.pid file should not prevent the service running
+    pgdata_directory = os.path.join(self.pgdata_directory, 'pgdata')
+    postmaster_pid_file =os.path.join(pgdata_directory, 'postmaster.pid')
+    content = '''\
+1074626
+/srv/slapgrid/slappart33/srv/runner/instance/slappart0/srv/postgresql
+1686241354
+5432
+/srv/slapgrid/slappart33/srv/runner/instance/slappart0/srv/postgresql
+10.0.156.45
+  5432001   1179658
+ready'''
+    with open(postmaster_pid_file, 'w') as file:
+      file.write(content)
+
+    self.recipe.install()
+
   def test_update_password(self):
     self.recipe.install()
     self.start_postgres_server()