Merge lp:~adam-collard/charm-helpers/pause-service-helper into lp:charm-helpers

[Adam Collard]

This branch adds service_pause and service_resume helpers to charmhelpers.core.host

The intention of these helpers is to go a bit further than service_stop and service_start by also adding an Upstart override to prevent the services starting at boot.

systemd support will land in a follow up branch, it should be noted that existing helpers for the services do not support systemd.

[Alberto Donato (ack)]

+1 with an inline comment.

review: Approve

[lp:~adam-collard/charm-helpers/pause-service-helper]

406. By Adam Collard on 2015-07-15

Default init_dir to None for better forwards compatability (ack's review)

[Chris Glass (tribaal)]

Looks great! Thanks for your contribution.

review: Approve

=== modified file 'VERSION'
--- VERSION	2015-05-20 14:31:33 +0000
+++ VERSION	2015-07-15 17:26:31 +0000
@@ -1,1 +1,1 @@
-0.3.2
+0.3.3

=== modified file 'charmhelpers/core/host.py'
--- charmhelpers/core/host.py	2015-06-01 17:08:32 +0000
+++ charmhelpers/core/host.py	2015-07-15 17:26:31 +0000
@@ -63,6 +63,36 @@
     return service_result
 
 
+def service_pause(service_name, init_dir=None):
+    """Pause a system service.
+
+    Stop it, and prevent it from starting again at boot."""
+    if init_dir is None:
+        init_dir = "/etc/init"
+    stopped = service_stop(service_name)
+    # XXX: Support systemd too
+    override_path = os.path.join(
+        init_dir, '{}.conf.override'.format(service_name))
+    with open(override_path, 'w') as fh:
+        fh.write("manual\n")
+    return stopped
+
+
+def service_resume(service_name, init_dir=None):
+    """Resume a system service.
+
+    Reenable starting again at boot. Start the service"""
+    # XXX: Support systemd too
+    if init_dir is None:
+        init_dir = "/etc/init"
+    override_path = os.path.join(
+        init_dir, '{}.conf.override'.format(service_name))
+    if os.path.exists(override_path):
+        os.unlink(override_path)
+    started = service_start(service_name)
+    return started
+
+
 def service(action, service_name):
     """Control a system service"""
     cmd = ['service', service_name, action]
@@ -140,11 +170,7 @@
 
 def add_user_to_group(username, group):
     """Add a user to a group"""
-    cmd = [
-        'gpasswd', '-a',
-        username,
-        group
-    ]
+    cmd = ['gpasswd', '-a', username, group]
     log("Adding user {} to group {}".format(username, group))
     subprocess.check_call(cmd)
 

=== modified file 'tests/core/test_host.py'
--- tests/core/test_host.py	2015-07-14 18:12:04 +0000
+++ tests/core/test_host.py	2015-07-15 17:26:31 +0000
@@ -1,5 +1,9 @@
+import os.path
 from collections import OrderedDict
 import subprocess
+from tempfile import mkdtemp
+from shutil import rmtree
+
 import apt_pkg
 
 from mock import patch, call
@@ -99,6 +103,34 @@
         service.assert_called_with('restart', service_name)
 
     @patch.object(host, 'service')
+    def test_pauses_a_service(self, service):
+        service_name = 'foo-service'
+        service.side_effect = [True]
+        tempdir = mkdtemp(prefix="test_pauses_a_service")
+        self.addCleanup(rmtree, tempdir)
+        self.assertTrue(host.service_pause(service_name, init_dir=tempdir))
+
+        service.assert_called_with('stop', service_name)
+        override_path = os.path.join(
+            tempdir, "{}.conf.override".format(service_name))
+        with open(override_path, "r") as fh:
+            override_contents = fh.read()
+        self.assertEqual("manual\n", override_contents)
+
+    @patch.object(host, 'service')
+    def test_resumes_a_service(self, service):
+        service_name = 'foo-service'
+        service.side_effect = [True]
+        tempdir = mkdtemp(prefix="test_resumes_a_service")
+        self.addCleanup(rmtree, tempdir)
+        self.assertTrue(host.service_resume(service_name, init_dir=tempdir))
+
+        service.assert_called_with('start', service_name)
+        override_path = os.path.join(
+            tempdir, "{}.conf.override".format(service_name))
+        self.assertFalse(os.path.exists(override_path))
+
+    @patch.object(host, 'service')
     def test_reloads_a_service(self, service):
         service_name = 'foo-service'
         service.side_effect = [True]