Add JWT login support

trustgraph-base/trustgraph/base/iam_client.py

@@ -112,6 +112,29 @@ class IamClient(RequestResponse):
             timeout=timeout,
         )
 
+    async def login(self, username, password, workspace="",
+                    timeout=IAM_TIMEOUT):
+        """Validate credentials and return ``(jwt, expires_iso)``.
+        ``workspace`` is optional; defaults at the server to the
+        OSS default workspace."""
+        resp = await self._request(
+            operation="login",
+            workspace=workspace,
+            username=username,
+            password=password,
+            timeout=timeout,
+        )
+        return resp.jwt, resp.jwt_expires
+
+    async def get_signing_key_public(self, timeout=IAM_TIMEOUT):
+        """Return the active JWT signing public key in PEM.  The
+        gateway calls this at startup and caches the result."""
+        resp = await self._request(
+            operation="get-signing-key-public",
+            timeout=timeout,
+        )
+        return resp.signing_key_public
+
 
 class IamClientSpec(RequestResponseSpec):
     def __init__(self, request_name, response_name):