Split backup writer off into separate task to allow for other data stores.

Python/vlbi.py

@@ -19,22 +19,36 @@ class ServerError(Exception):
     def __str__(self):
         return repr(self.value)
 
+"""BackupWriter is responsible for writing backups of requests to disk.
+
+May be reimplemented to write to some other storage type instead.
+"""
+class BackupWriter(object):
+    def __init__(self, outdir):
+        self.outdir = outdir
+
+    def write(self, request):
+        filename = "{0}-{1}-{2}-{3}.json".format(request["method"],
+                request["auth"]["username"],
+                request["auth"]["facility"],
+                datetime.datetime.utcnow().isoformat())
+
+        with open(os.path.join(self.outdir, filename), "w") as f:
+            json.dump(request, f)
+
 class Client(object):
     headers = {'content-type': 'application/json'}
 
-    def __init__(self, server, facility, username, password, backup=False, backupDir="./backup"):
+    def __init__(self, server, facility, username, password, backup=None):
         self.server = server
         self.facility = facility
         self.username = username
         self.password = password
         self.backup = backup
-        self.backupDir = backupDir
 
     def post(self, request):
         if self.backup:
-            filename = "{0}-{1}-{2}-{3}.json".format(request["method"], self.facility, self.username, datetime.datetime.utcnow().isoformat())
-            with open(os.path.join(self.backupDir, filename), "w") as f:
-                json.dump(request, f)
+            backup.write(request)
 
         response = requests.post(self.server, data=json.dumps(request), headers=self.headers).json()