Add API endpoint to get a Phabricator Revision from Lando

dev-requirements.txt

@@ -25,3 +25,6 @@ mccabe==0.6.1 \
 py==1.4.33 \
     --hash=sha256:81b5e37db3cc1052de438375605fb5d3b3e97f950f415f9143f04697c684d7eb \
     --hash=sha256:1f9a981438f2acc20470b301a07a496375641f902320f70e31916fe3377385a9
+requests-mock==1.3.0 \
+    --hash=sha256:23edd6f7926aa13b88bf79cb467632ba2dd5a253034e9f41563f60ed305620c7
+

docker-compose.yml

@@ -10,9 +10,12 @@ services:
       dockerfile: ./docker/Dockerfile-dev
     volumes:
       - ./:/app
+    ports:
+      - "8888:80"
     environment:
       - PORT=80
       - VERSION_PATH=/version.json
+      - PHABRICATOR_URL=https://mozphab.dev.mozaws.net
   py3-linter:
     build:
       context: ./

landoapi/api/revisions.py

@@ -1,18 +1,104 @@
 # This Source Code Form is subject to the terms of the Mozilla Public
 # License, v. 2.0. If a copy of the MPL was not distributed with this
 # file, You can obtain one at http://mozilla.org/MPL/2.0/.
+"""
+Revision API
+See the OpenAPI Specification for this API in the spec/swagger.yml file.
+"""
 from connexion import problem
+from landoapi.phabricator_client import PhabricatorClient
 
 
-def search():
-    pass
+def get(api_key, revision_id):
+    """ API endpoint at /revisions/{id} to get revision data. """
+    phab = PhabricatorClient(api_key)
+    revision = phab.get_revision(id=revision_id)
 
+    if not revision:
+        # We could not find a matching revision.
+        return problem(
+            404,
+            'Revision not found',
+            'The requested revision does not exist',
+            type='https://developer.mozilla.org/en-US/docs/Web/HTTP/Status/404'
+        )
 
-def get(id):
-    # We could not find a matching revision.
-    return problem(
-        404,
-        'Revision not found',
-        'The requested revision does not exist',
-        type='https://developer.mozilla.org/en-US/docs/Web/HTTP/Status/404'
-    )
+    return _format_revision(phab, revision, include_parents=True), 200
+
+
+def _format_revision(
+    phab, revision, include_parents=False, last_author=None, last_repo=None
+):
+    """ Formats a revision given by Phabricator to match Lando's spec.
+
+    See the swagger.yml spec for the Revision definition.
+
+    Args:
+        phab: The PhabricatorClient to use to make additional requests.
+        revision: The initial revision to format.
+        include_parents: A flag to choose whether this method will recursively
+            load parent revisions and format them as well.
+        last_author: A hash of the author who created the revision. This is
+            mainly used by this method itself when recursively loading parent
+            revisions so as to prevent excess requests for what is often the
+            same author on each parent revision.
+        last_repo: A hash of the repo that this revision belongs to. This is
+            mainly used by this method itself when recursively loading parent
+            revisions so as to prevent excess requests for what is often the
+            same repo on each parent revision.
+    Returns:
+        A hash of the formatted revision information.
+    """
+
+    # Load the author if it isn't the same as the child revision's author.
+    if last_author and revision['authorPHID'] == last_author['phid']:
+        author = last_author
+    else:
+        raw_author = phab.get_user(revision['authorPHID'])
+        author = {
+            'phid': raw_author['phid'],
+            'username': raw_author['userName'],
+            'real_name': raw_author['realName'],
+            'url': raw_author['uri'],
+            'image_url': raw_author['image'],
+        }
+
+    # Load the repo if it isn't the same as the child revision's repo.
+    if last_repo and revision['repositoryPHID'] == last_repo['phid']:
+        repo = last_repo
+    else:
+        raw_repo = phab.get_repo(revision['repositoryPHID'])
+        repo = {
+            'phid': raw_repo['phid'],
+            'short_name': raw_repo['name'],
+            'full_name': raw_repo['fullName'],
+            'url': raw_repo['uri'],
+        }
+
+    # This recursively loads the parent of a revision, and the parents of
+    # that parent, and so on, ultimately creating a linked-list type structure
+    # that connects the dependent revisions.
+    parent_revisions = []
+    if include_parents:
+        parent_phids = revision['auxiliary']['phabricator:depends-on']
+        for parent_phid in parent_phids:
+            parent_revision_data = phab.get_revision(phid=parent_phid)
+            if parent_revision_data:
+                parent_revisions.append(
+                    _format_revision(phab, parent_revision_data, True)
+                )
+
+    return {
+        'id': int(revision['id']),
+        'phid': revision['phid'],
+        'url': revision['uri'],
+        'date_created': int(revision['dateCreated']),
+        'date_modifed': int(revision['dateModified']),
+        'status': int(revision['status']),
+        'status_name': revision['statusName'],
+        'summary': revision['summary'],
+        'test_plan': revision['testPlan'],
+        'author': author,
+        'repo': repo,
+        'parent_revisions': parent_revisions,
+    }

landoapi/phabricator_client.py

@@ -0,0 +1,108 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+import os
+import requests
+
+
+class PhabricatorClient:
+    """ A class to interface with Phabricator's Conduit API. 
+
+    All request methods in this class will throw a PhabricatorAPIException if 
+    Phabricator returns an error response. If there is an actual problem with
+    the request to the server or decoding the JSON response, this class will
+    bubble up the exception. These exceptions can be one of the request library
+    exceptions or a JSONDecodeError.
+    """
+
+    def __init__(self, api_key):
+        self.api_url = os.getenv('PHABRICATOR_URL') + '/api'
+        self.api_key = api_key
+
+    def get_revision(self, id=None, phid=None):
+        """ Gets a revision as defined by the Phabricator API.
+
+        Args:
+            id: The id of the revision if known. This can be in the form of 
+                an integer or an integer prefixed with 'D', e.g. 'D12345'.
+            phid: The phid of the revision to be used if the id isn't provided. 
+
+        Returns: 
+            A hash of the revision data just as it is returned by Phabricator.
+            Returns None, if the revision doesn't exist, or if the api key that 
+            was used to create the PhabricatorClient doesn't have permission to 
+            view the revision. 
+        """
+        result = None
+        if id:
+            id_num = str(id).strip().replace('D', '')
+            result = self._GET('/differential.query', {'ids[]': [id_num]})
+        elif phid:
+            result = self._GET('/differential.query', {'phids[]': [phid]})
+        return result[0] if result else None
+
+    def get_current_user(self):
+        """ Gets the information of the user making this request.
+
+        Returns:
+            A hash containing the information of the user that owns the api key
+            that was used to initialize this PhabricatorClient.
+        """
+        return self._GET('/user.whoami')
+
+    def get_user(self, phid):
+        """ Gets the information of the user based on their phid. 
+
+        Args:
+            phid: The phid of the user to lookup.
+
+        Returns:
+            A hash containing the user information, or an None if the user 
+            could not be found.
+        """
+        result = self._GET('/user.query', {'phids[]': [phid]})
+        return result[0] if result else None
+
+    def get_repo(self, phid):
+        """ Get basic information about a repo based on its phid. 
+
+        Args:
+            phid: The phid of the repo to lookup.
+
+        Returns:
+            A hash containing the repo info, or None if the repo isn't found.
+        """
+        result = self._GET('/phid.query', {'phids[]': [phid]})
+        return result.get(phid) if result else None
+
+    def _request(self, url, data=None, params=None, method='GET'):
+        data = data if data else {}
+        data['api.token'] = self.api_key
+        response = requests.request(
+            method=method,
+            url=self.api_url + url,
+            params=params,
+            data=data,
+            timeout=10
+        ).json()
+
+        if response['error_code']:
+            exp = PhabricatorAPIException(response.get('error_info'))
+            exp.error_code = response.get('error_code')
+            exp.error_info = response.get('error_info')
+            raise exp
+
+        return response.get('result')
+
+    def _GET(self, url, data=None, params=None):
+        return self._request(url, data, params, 'GET')
+
+    def _POST(self, url, data=None, params=None):
+        return self._request(url, data, params, 'POST')
+
+
+class PhabricatorAPIException(Exception):
+    """ An exception class to handle errors from the Phabricator API """
+    error_code = None
+    error_info = None