Dry run and comparing more than just version when updating apps.

.coveragerc

@@ -4,7 +4,7 @@ source = apployer/
 [report]
 exclude_lines = def __repr__
 # TODO set 100
-fail_under = 91
+fail_under = 92
 
 # we won't work on those files and they will be eventually obsolete
 omit =

.pylintrc

@@ -9,7 +9,7 @@
 # --enable=similarities". If you want to run only the classes checker, but have
 # no Warning level messages displayed, use"--disable=all --enable=classes
 # --disable=W"
-disable=W1620,E1607,I0021,E1601,W1618,W1613,W1607,E1604,W1611,W1632,W1628,W1637,W1625,W1609,W1638,W1621,W1640,W1635,E1605,W1623,W0704,W1619,W1622,W1614,W1604,W1606,E1606,W1636,W1629,I0020,W1610,W1603,W1601,W1624,W1602,E1602,W1633,W1634,W1630,E1603,E1608,W1605,W1617,W1639,W1615,W1612,W1626,W1627,W1616,W1608,too-few-public-methods,fixme,locally-disabled,file-ignored
+disable=too-few-public-methods,fixme,locally-disabled,file-ignored
 
 [REPORTS]
 

apployer/app_compare.py

@@ -0,0 +1,165 @@
+#
+# Copyright (c) 2016 Intel Corporation
+#
+# Licensed 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.
+#
+
+"""
+Comparing an application from appstack to its counterpart in the live environment.
+"""
+
+import logging
+import pkg_resources
+
+import datadiff
+from requests.structures import CaseInsensitiveDict
+
+from . import cf_api
+from . import cf_cli
+
+_log = logging.getLogger(__name__) # pylint: disable=invalid-name
+
+
+def should_update(app):
+    """Checks whether an application should be updated (or created from scratch) in the live
+    Cloud Foundry environment.
+
+    Args:
+        app (`apployer.appstack.AppConfig`): An application.
+
+    Returns:
+        bool: True if the app should be pushed, False otherwise.
+    """
+    try:
+        app_guid = cf_cli.get_app_guid(app.name)
+    except cf_cli.CommandFailedError as ex:
+        _log.debug(str(ex))
+        _log.info("Failed to get GUID of app %s. Assuming it doesn't exist yet. "
+                  "Will need to push it...", app.name)
+        return True
+    app_summary = cf_api.get_app_summary(app_guid)
+    app_properties = app.app_properties
+
+    appstack_version, live_env_version = _get_app_versions(app_properties, app_summary)
+    if appstack_version > live_env_version:
+        _log.info("Appstack's version of the app (%s) is higher than in the live env (%s). "
+                  "Will update...", appstack_version, live_env_version)
+        return True
+    elif appstack_version < live_env_version:
+        _log.info("Appstack's version of the app (%s) is lower than in the live env (%s). "
+                  "Won't push, because that would downgrade the app...",
+                  appstack_version, live_env_version)
+        return False
+
+    return _properties_differ(app_properties, app_summary)
+
+
+def _get_app_versions(app_properties, app_summary):
+    """
+    Args:
+        app_properties (dict): Application's properties from appstack.
+        app_summary (dict): Application's properties from Cloud Foundry.
+
+    Returns:
+        (`pkg_resources.SetuptoolsVersion`, `pkg_resources.SetuptoolsVersion`): Tuple in form:
+            (app_version_in_appstack, app_version_in_live_env).
+            If version isn't found, then the lowest possible version will be returned.
+    """
+    appstack_version = app_properties.get('env', {}).get('VERSION', '')
+    live_env_version = app_summary.get('environment_json', {}).get('VERSION', '')
+    # empty version string will be parsed to the lowest possible version
+    return (pkg_resources.parse_version(appstack_version),
+            pkg_resources.parse_version(live_env_version))
+
+
+def _properties_differ(app_properties, app_summary):
+    """Compares application's properties from appstack to those taken from a live environment.
+
+    Args:
+        app_properties (dict): Application's properties from appstack.
+        app_summary (dict): Application's properties from Cloud Foundry.
+
+    Returns:
+        bool: True if one of the properties present in `app_properties` is different in
+            `app_summary`. False otherwise.
+    """
+    for key, value in app_properties.items():
+        if key == 'env':
+            if not _dict_is_part_of(app_summary['environment_json'], value):
+                _log.info("Differences in application's env:\n%s",
+                          datadiff.diff(app_summary['environment_json'], value,
+                                        fromfile='live env', tofile='appstack'))
+                return True
+        elif key in ('disk_quota', 'memory'):
+            # Values in the manifest will be strings and have suffix M, MB, G or GB,
+            # while values in summary will be ints specifying the number of megabytes.
+            megabytes_in_properties = _normalize_to_megabytes(value)
+            if megabytes_in_properties != app_summary[key]:
+                _log.info("Difference in application's %s field: %s (live env) vs. %s (appstack).",
+                          key, app_summary[key], megabytes_in_properties)
+                return True
+        elif key == 'services':
+            summary_services = [service['name'] for service in app_summary[key]]
+            if not set(value).issubset(set(summary_services)):
+                _log.info("Difference in application's services: \n%s",
+                          datadiff.diff(app_summary[key], value,
+                                        fromfile='live env', tofile='appstack'))
+                return True
+        elif key == 'host':
+            summary_hosts = [route['host'] for route in app_summary['routes']]
+            if value not in summary_hosts:
+                _log.info("Application's hosts in live env don't contain %s.", value)
+                return True
+        else:
+            if value != app_summary[key]:
+                _log.info("Difference in application's %s field: %s (live env) vs. %s (appstack).",
+                          key, app_summary[key], value)
+                return True
+    return False
+
+
+def _dict_is_part_of(dict_a, dict_b):
+    """
+    Checks whether dict_b is a part of dict_a.
+    That is if dict_b is dict_a, just with some (or none) keys removed.
+
+    Args:
+        dict_a (dict):
+        dict_b (dict):
+
+    Return:
+        bool: True if dict_a contains dict_b.
+    """
+    dict_a, dict_b = CaseInsensitiveDict(dict_a), CaseInsensitiveDict(dict_b)
+    for key, value in dict_b.items():
+        if key not in dict_a or dict_a[key] != value:
+            return False
+    return True
+
+
+def _normalize_to_megabytes(value):
+    """
+    Args:
+        value (str): A string with a number and a size suffix, like 2GB or 300M.
+
+    Returns:
+        int: Number of megabytes represented by the `value`.
+    """
+    if value.endswith('M'):
+        return int(value[:-1])
+    elif value.endswith('MB'):
+        return int(value[:-2])
+    elif value.endswith('G'):
+        return int(value[:-1]) * 1024
+    elif value.endswith('GB'):
+        return int(value[:-2]) * 1024

apployer/cf_api.py

@@ -66,6 +66,7 @@ def delete_service_binding(binding):
         raise cf_cli.CommandFailedError('Failed to delete a service binding. CF response: {}'
                                         .format(cmd_output))
 
+
 def get_app_name(app_guid):
     """
     Args:
@@ -78,6 +79,18 @@ def get_app_name(app_guid):
     return app_desctiption['entity']['name']
 
 
+def get_app_summary(app_guid):
+    """Gets a summary of the application's state. This includes its full configuration.
+
+    Args:
+        app_guid (str): Application's GUID.
+
+    Returns:
+        dict: Application's summary. Contains fields like "services", "memory", "buildpack", etc.
+    """
+    return _cf_curl_get('/v2/apps/{}/summary'.format(app_guid))
+
+
 def get_upsi_credentials(service_guid):
     """Gets the credentials (configuration) of a user-provided service instance.
 

apployer/cf_cli.py

@@ -91,7 +91,7 @@ def bind_service(app_name, instance_name):
 def buildpacks():
     """
     Returns:
-        list[`BuildpackDescription`]: A list of buildpacks on the environment.
+        list[`BuildpackDescription`]: A list of buildpacks in the environment.
     """
     out = get_command_output([CF, 'buildpacks'])
     buildpack_lines = out.splitlines()[3:]
@@ -216,6 +216,18 @@ def env(app_name):
     return get_command_output([CF, 'env', app_name])
 
 
+def get_app_guid(app_name):
+    """
+    Args:
+        app_name (str): Name of a service instace (can be a user-provided one).
+
+    Returns:
+        str: GUID of the application that can be used in API calls.
+    """
+    cmd_output = get_command_output([CF, 'app', '--guid', app_name])
+    return cmd_output.split()[0]
+
+
 def get_service_guid(service_name):
     """
     Args:
@@ -287,6 +299,16 @@ def service(service_name):
     return get_command_output([CF, 'service', service_name])
 
 
+def service_brokers():
+    """
+    Returns:
+        set[str]: A set of brokers (their names) in the environment.
+    """
+    out = get_command_output([CF, 'service-brokers'])
+    broker_lines = out.splitlines()[3:]
+    return set([line.split()[0] for line in broker_lines])
+
+
 def update_buildpack(buildpack_name, buildpack_path):
     """Updates a buildpack.