vucm: run: add config_prefix kwarg

Author: rnovatorov

enapter/vucm/app.py

@@ -6,10 +6,10 @@
 from .ucm import UCM
 
 
-async def run(device_factory):
+async def run(device_factory, config_prefix=None):
     enapter.log.configure(level=enapter.log.LEVEL or "info")
 
-    config = Config.from_env()
+    config = Config.from_env(prefix=config_prefix)
 
     async with App(config=config, device_factory=device_factory) as app:
         await app.join()

enapter/vucm/config.py

@@ -7,7 +7,9 @@
 
 class Config:
     @classmethod
-    def from_env(cls, prefix="ENAPTER_VUCM_", env=os.environ):
+    def from_env(cls, prefix=None, env=os.environ):
+        if prefix is None:
+            prefix = "ENAPTER_VUCM_"
         try:
             blob = os.environ[prefix + "BLOB"]
         except KeyError: