Add offline support using Task.set_offline() and Task.import_offline_session()

trains/backend_api/api_proxy.py

@@ -31,7 +31,7 @@ class ApiServiceProxy(object):
                     ]]
 
             # get the most advanced service version that supports our api
-            version = [str(v) for v in ApiServiceProxy._available_versions if Version(Session.api_version) >= v][-1]
+            version = [str(v) for v in ApiServiceProxy._available_versions if Session.check_min_api_version(v)][-1]
             self.__dict__["__wrapped_version__"] = Session.api_version
             name = ".v{}.{}".format(
                 version.replace(".", "_"), self.__dict__.get("__wrapped_name__")

trains/backend_api/session/defs.py

@@ -8,3 +8,4 @@ ENV_ACCESS_KEY = EnvEntry("TRAINS_API_ACCESS_KEY", "ALG_API_ACCESS_KEY")
 ENV_SECRET_KEY = EnvEntry("TRAINS_API_SECRET_KEY", "ALG_API_SECRET_KEY")
 ENV_VERBOSE = EnvEntry("TRAINS_API_VERBOSE", "ALG_API_VERBOSE", type=bool, default=False)
 ENV_HOST_VERIFY_CERT = EnvEntry("TRAINS_API_HOST_VERIFY_CERT", "ALG_API_HOST_VERIFY_CERT", type=bool, default=True)
+ENV_OFFLINE_MODE = EnvEntry("TRAINS_OFFLINE_MODE", "ALG_OFFLINE_MODE", type=bool)

trains/backend_api/session/session.py

@@ -11,7 +11,8 @@ from requests.auth import HTTPBasicAuth
 from six.moves.urllib.parse import urlparse, urlunparse
 
 from .callresult import CallResult
-from .defs import ENV_VERBOSE, ENV_HOST, ENV_ACCESS_KEY, ENV_SECRET_KEY, ENV_WEB_HOST, ENV_FILES_HOST
+from .defs import ENV_VERBOSE, ENV_HOST, ENV_ACCESS_KEY, ENV_SECRET_KEY, ENV_WEB_HOST, \
+    ENV_FILES_HOST, ENV_OFFLINE_MODE
 from .request import Request, BatchRequest  # noqa: F401
 from .token_manager import TokenManager
 from ..config import load
@@ -50,6 +51,8 @@ class Session(TokenManager):
     _write_session_timeout = (300.0, 300.)
     _sessions_created = 0
     _ssl_error_count_verbosity = 2
+    _offline_mode = ENV_OFFLINE_MODE.get()
+    _offline_default_version = '2.5'
 
     _client = [(__package__.partition(".")[0], __version__)]
 
@@ -153,6 +156,9 @@ class Session(TokenManager):
 
         self.client = ", ".join("{}-{}".format(*x) for x in self._client)
 
+        if self._offline_mode:
+            return
+
         self.refresh_token()
 
         # update api version from server response
@@ -197,6 +203,9 @@ class Session(TokenManager):
               server-side permissions have changed but are not reflected in the current token. Refreshing the token will
               generate a token with the updated permissions.
         """
+        if self._offline_mode:
+            return None
+
         host = self.host
         headers = headers.copy() if headers else {}
         headers[self._WORKER_HEADER] = self.worker
@@ -406,6 +415,9 @@ class Session(TokenManager):
         """
         self.validate_request(req_obj)
 
+        if self._offline_mode:
+            return None
+
         if isinstance(req_obj, BatchRequest):
             # TODO: support async for batch requests as well
             if async_enable:
@@ -526,11 +538,14 @@ class Session(TokenManager):
 
         # If no session was created, create a default one, in order to get the backend api version.
         if cls._sessions_created <= 0:
-            # noinspection PyBroadException
-            try:
-                cls()
-            except Exception:
-                pass
+            if cls._offline_mode:
+                cls.api_version = cls._offline_default_version
+            else:
+                # noinspection PyBroadException
+                try:
+                    cls()
+                except Exception:
+                    pass
 
         return version_tuple(cls.api_version) >= version_tuple(str(min_api_version))