[ADD] DCOS-367 As a user, I want to scale the application

fit tests

fix scale json

fix dcos help test

update after review, add negative tests

fix help test

move parse_float to dcoscli.marathon.main

fix test help marathon testx

cli/dcoscli/marathon/main.py

@@ -22,6 +22,7 @@ Usage:
     dcos marathon task show <task-id>
     dcos marathon group add [<group-resource>]
     dcos marathon group list [--json]
+    dcos marathon group scale [--force] <group-id> <scale-factor>
     dcos marathon group show [--group-version=<group-version>] <group-id>
     dcos marathon group remove [--force] <group-id>
     dcos marathon group update [--force] <group-id> [<properties>...]
@@ -96,6 +97,8 @@ Positional Arguments:
                                 stdin.
 
     <task-id>                   The task id
+
+    <scale-factor>              The factor to scale an application group by
 """
 import json
 import os
@@ -240,6 +243,11 @@ def _cmds():
             arg_keys=['<group-id>', '<properties>', '--force'],
             function=_group_update),
 
+        cmds.Command(
+            hierarchy=['marathon', 'group', 'scale'],
+            arg_keys=['<group-id>', '<scale-factor>', '--force'],
+            function=_group_scale),
+
         cmds.Command(
             hierarchy=['marathon', 'about'],
             arg_keys=[],
@@ -645,6 +653,25 @@ def _update(app_id, properties, force):
     return 0
 
 
+def _group_scale(group_id, scale_factor, force):
+    """
+    :param group_id: the id of the group
+    :type group_id: str
+    :param scale_factor: scale factor for application group
+    :type scale_factor: str
+    :param force: whether to override running deployments
+    :type force: bool
+    :returns: process return code
+    :rtype: int
+    """
+
+    client = marathon.create_client()
+    scale_factor = util.parse_float(scale_factor)
+    deployment = client.scale_group(group_id, scale_factor, force)
+    emitter.publish('Created deployment {}'.format(deployment))
+    return 0
+
+
 def _validate_update(current_resource, properties, schema):
     """
     Validate resource ("app" or "group") update

cli/tests/data/help/marathon.txt

@@ -22,6 +22,7 @@ Usage:
     dcos marathon task show <task-id>
     dcos marathon group add [<group-resource>]
     dcos marathon group list [--json]
+    dcos marathon group scale [--force] <group-id> <scale-factor>
     dcos marathon group show [--group-version=<group-version>] <group-id>
     dcos marathon group remove [--force] <group-id>
     dcos marathon group update [--force] <group-id> [<properties>...]
@@ -96,3 +97,5 @@ Positional Arguments:
                                 stdin.
 
     <task-id>                   The task id
+
+    <scale-factor>              The factor to scale an application group by

cli/tests/data/marathon/groups/scale.json

@@ -0,0 +1,15 @@
+{
+  "groups": [
+    {
+      "apps": [
+        {
+          "id": "sleep",
+          "cmd": "sleep 1000",
+          "instances": 1
+        }
+      ],
+      "id": "sleep"
+    }
+  ],
+  "id": "scale-group"
+}

cli/tests/integrations/test_marathon.py

@@ -39,6 +39,7 @@ Usage:
     dcos marathon task show <task-id>
     dcos marathon group add [<group-resource>]
     dcos marathon group list [--json]
+    dcos marathon group scale [--force] <group-id> <scale-factor>
     dcos marathon group show [--group-version=<group-version>] <group-id>
     dcos marathon group remove [--force] <group-id>
     dcos marathon group update [--force] <group-id> [<properties>...]
@@ -113,6 +114,8 @@ Positional Arguments:
                                 stdin.
 
     <task-id>                   The task id
+
+    <scale-factor>              The factor to scale an application group by
 """
     assert_command(['dcos', 'marathon', '--help'],
                    stdout=stdout)

cli/tests/integrations/test_marathon_groups.py

@@ -123,6 +123,56 @@ def test_update_missing_field():
             "Possible properties are: ")
 
 
+def test_scale_group():
+    _deploy_group('tests/data/marathon/groups/scale.json')
+    returncode, stdout, stderr = exec_command(['dcos', 'marathon', 'group',
+                                               'scale', 'scale-group', '2'])
+    assert stderr == b''
+    assert returncode == 0
+    watch_all_deployments()
+    returncode, stdout, stderr = exec_command(
+        ['dcos', 'marathon', 'group', 'show',
+         'scale-group'])
+    res = json.loads(stdout.decode('utf-8'))
+
+    assert res['groups'][0]['apps'][0]['instances'] == 2
+    _remove_group('scale-group')
+
+
+def test_scale_group_not_exist():
+    returncode, stdout, stderr = exec_command(['dcos', 'marathon', 'group',
+                                               'scale', 'scale-group', '2'])
+    assert stderr == b''
+    watch_all_deployments()
+    returncode, stdout, stderr = exec_command(
+        ['dcos', 'marathon', 'group', 'show',
+         'scale-group'])
+    res = json.loads(stdout.decode('utf-8'))
+
+    assert len(res['apps']) == 0
+    _remove_group('scale-group')
+
+
+def test_scale_group_when_scale_factor_negative():
+    _deploy_group('tests/data/marathon/groups/scale.json')
+    returncode, stdout, stderr = exec_command(['dcos', 'marathon', 'group',
+                                               'scale', 'scale-group', '-2'])
+    assert b'Command not recognized' in stdout
+    assert returncode == 1
+    watch_all_deployments()
+    _remove_group('scale-group')
+
+
+def test_scale_group_when_scale_factor_not_float():
+    _deploy_group('tests/data/marathon/groups/scale.json')
+    returncode, stdout, stderr = exec_command(['dcos', 'marathon', 'group',
+                                               'scale', 'scale-group', '1.a'])
+    assert stderr == b'Error parsing string as float\n'
+    assert returncode == 1
+    watch_all_deployments()
+    _remove_group('scale-group')
+
+
 def _remove_group(group_id):
     assert_command(['dcos', 'marathon', 'group', 'remove', group_id])
 

dcos/marathon.py

@@ -388,6 +388,35 @@ class Client(object):
         deployment = response.json()['deploymentId']
         return deployment
 
+    def scale_group(self, group_id, scale_factor, force=None):
+        """Scales a group with the requested scale-factor.
+        :param group_id: the ID of the group to scale
+        :type group_id: str
+        :param scale_factor: the requested value of scale-factor
+        :type scale_factor: float
+        :param force: whether to override running deployments
+        :type force: bool
+        :returns: the resulting deployment ID
+        :rtype: bool
+        """
+
+        group_id = self.normalize_app_id(group_id)
+
+        if not force:
+            params = None
+        else:
+            params = {'force': 'true'}
+
+        url = self._create_url('v2/groups{}'.format(group_id))
+
+        response = http.put(url,
+                            params=params,
+                            json={'scaleBy': scale_factor},
+                            timeout=self._timeout)
+
+        deployment = response.json()['deploymentId']
+        return deployment
+
     def stop_app(self, app_id, force=None):
         """Scales an application to zero instances.
 

dcos/util.py

@@ -454,6 +454,25 @@ def parse_int(string):
         raise DCOSException('Error parsing string as int')
 
 
+def parse_float(string):
+    """Parse string and an float
+
+    :param string: string to parse as an float
+    :type string: str
+    :returns: the float value of the string
+    :rtype: float
+    """
+
+    try:
+        return float(string)
+    except:
+        logger.error(
+            'Unhandled exception while parsing string as float: %r',
+            string)
+
+        raise DCOSException('Error parsing string as float')
+
+
 def render_mustache_json(template, data):
     """Render the supplied mustache template and data as a JSON value