Construct Client from CloudFoundry service binding

CHANGELOG.md

@@ -11,13 +11,17 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 * Add [CONTRIBUTING.md] and [SECURITY.md] [#92]
 * This project is now following the [Best Practices] set forth by the
   Core Infrastructure Initiative! See [CII badge details]. [#92]
+* Add `construct_from_cf_env` method to construct client instances from
+  Data Attribute Recommendation service binding on SAP Business Technology
+  Platform. [#97]
 
 [CONTRIBUTING.md]: /CONTRIBUTING.md
 [SECURITY.md]: /SECURITY.md
 [Best Practices]: https://www.coreinfrastructure.org/programs/best-practices-program/
 [CII badge details]: https://bestpractices.coreinfrastructure.org/en/projects/4514
 
 [#92]: https://github.com/SAP/data-attribute-recommendation-python-sdk/pull/92
+[#97]: https://github.com/SAP/data-attribute-recommendation-python-sdk/pull/92
 
 ### Changed
 

requirements.txt

@@ -1,2 +1,3 @@
-requests==2.23.0
-typing-extensions==3.7.4.1
+cfenv==0.5.3
+requests==2.25.1
+typing-extensions==3.10.0.0

sap/aibus/dar/client/base_client.py

@@ -3,6 +3,8 @@
 """
 from typing import TypeVar, Type
 
+from cfenv import AppEnv
+
 from sap.aibus.dar.client.util.credentials import (
     CredentialsSource,
     OnlineCredentialsSource,
@@ -87,6 +89,23 @@ def construct_from_jwt(cls: Type[DARClient], dar_url: str, token: str) -> DARCli
         source = StaticCredentialsSource(token)
         return cls(dar_url, source)
 
+    @classmethod
+    def construct_from_cf_env(cls: Type[DARClient]) -> DARClient:
+        """
+        Constructs a DARClient from service binding in a CloudFoundry app.
+
+        This is useful when the SDK is used in a CloudFoundry application on the
+        SAP Business Technology Platform where the application is bound to an instance
+        of the Data Attribute Recommendation service.
+
+        This constructor assumes that only one instance of the service is bound
+        to the app.
+        :return: the client instance
+        """
+        env = AppEnv()
+        dar = env.get_service(label="data-attribute-recommendation")
+        return cls.construct_from_service_key(dar.credentials)
+
 
 class BaseClientWithSession(BaseClient):
     """

setup.py

@@ -27,7 +27,7 @@ def get_long_version():
     author="Michael Haas",
     author_email="michael.haas01@sap.com",
     url="https://github.com/sap/data-attribute-recommendation-python-sdk",
-    install_requires=["requests>=2.20.0", "typing-extensions>=3.7.4.1"],
+    install_requires=["requests~=2.20.0", "typing-extensions~=3.7.4.1", "cfenv~=0.5.3"],
     packages=find_packages(exclude=["tests"]),
     include_package_data=True,
     python_requires="~=3.5",

tests/sap/aibus/dar/client/test_data_manager_client.py

@@ -1,4 +1,5 @@
 from io import BytesIO, StringIO
+import json
 from typing import Any
 from unittest.mock import create_autospec, call, Mock, MagicMock
 
@@ -122,6 +123,51 @@ def test_create_from_jwt_enforces_https(self):
             # RFC 4266 URLs should also be rejected
             self.clazz.construct_from_jwt("gopher://host:70/1", jwt)
 
+    def test_create_from_cf_env(self, monkeypatch):
+        vcap_services = {
+            "data-attribute-recommendation-staging": [
+                {
+                    "binding_guid": "XXXX",
+                    "binding_name": None,
+                    "credentials": {
+                        "swagger": {
+                            "dm": self.dar_url + "data-manager/doc/ui",
+                            "inference": self.dar_url + "inference/doc/ui",
+                            "mm": self.dar_url + "model-manager/doc/ui",
+                        },
+                        "uaa": {
+                            "clientid": self.clientid,
+                            "clientsecret": self.clientsecret,
+                            "identityzone": "dar-saas-test-app",
+                            "identityzoneid": "XXX",
+                            "subaccountid": "XXX",
+                            "tenantid": "XXX",
+                            "tenantmode": "dedicated",
+                            "uaadomain": "authentication.sap.hana.ondemand.com",
+                            "url": self.uaa_url,
+                            "verificationkey": "XXX",
+                            "xsappname": "XXX",
+                            "zoneid": "XXXX",
+                        },
+                        "url": self.dar_url,
+                    },
+                    "instance_guid": "XXX",
+                    "instance_name": "dar-instance-3",
+                    "label": "data-attribute-recommendation",
+                    "name": "dar-instance-3",
+                    "plan": "standard",
+                    "provider": None,
+                    "syslog_drain_url": None,
+                    "tags": [],
+                    "volume_mounts": [],
+                }
+            ]
+        }
+
+        monkeypatch.setenv("VCAP_SERVICES", json.dumps(vcap_services))
+        client = self.clazz.construct_from_cf_env()
+        self._assert_fields_initialized(client)
+
     def _assert_fields_initialized(self, client):
         assert isinstance(client.credentials_source, OnlineCredentialsSource)
         assert client.credentials_source.clientid == self.clientid