[common] Make the "status legend" explicit

Having characters explained in a logged string does
not make understanding the code easy.

beat/cmdline/common.py

@@ -48,6 +48,8 @@ import six
 import termcolor
 import simplejson
 
+from enum import Enum, unique
+
 from beat.core import dataformat
 from beat.core import database
 from beat.core import library
@@ -124,6 +126,19 @@ TYPE_PLURAL = {
 }
 
 
+@unique
+class ModificationStatus(Enum):
+    """This enum describes the state of possible changes between a local asset
+    and it's remote counter part"""
+
+    NO_CHANGES = ""
+    REMOTE_ONLY_AVAILABLE = "r"
+    LOCAL_ONLY_AVAILABLE = "l"
+    DOC_CHANGED = "d"
+    CONTENT_CHANGED = "+"
+    BOTH_CHANGED = "*"
+
+
 def recursive_rmdir_if_empty(path, stop_at):
     """Recursively removes empty directories until a certain top directory"""
 
@@ -1257,14 +1272,16 @@ def status(webapi, prefix, asset_type):
 
             if contents:
                 if doc:
-                    symbol = "*"  # both contents and doc changed
+                    symbol = (
+                        ModificationStatus.BOTH_CHANGED
+                    )  # both contents and doc changed
                 else:
-                    symbol = "+"  # only contents changed
+                    symbol = ModificationStatus.CONTENT_CHANGED  # only contents changed
             else:
                 if doc:
-                    symbol = "d"  # only docs changed
+                    symbol = ModificationStatus.DOC_CHANGED  # only docs changed
                 else:
-                    symbol = ""  # no changes
+                    symbol = ModificationStatus.NO_CHANGES  # no changes
 
             if symbol:
                 logger.info(
@@ -1282,7 +1299,7 @@ def status(webapi, prefix, asset_type):
     # whatever is not listed remotely
     for key in set(local) - set(remote.keys()):
         logger.info("[l] %s/%s", TYPE_PLURAL[asset_type], key)
-        retval[key] = "l"
+        retval[key] = ModificationStatus.LOCAL_ONLY_AVAILABLE
 
     # whatever is not listed locally
     for key in set(remote.keys()) - set(local):
@@ -1292,7 +1309,7 @@ def status(webapi, prefix, asset_type):
             key,
             remote[key]["creation_date"],
         )
-        retval[key] = "r"
+        retval[key] = ModificationStatus.REMOTE_ONLY_AVAILABLE
 
     return 0, retval
 
@@ -1398,8 +1415,9 @@ def push(
         return 0
 
     # flush all final candidates
-    for asset_name, legend_symbol in candidates.items():
-        if legend_symbol == "r":  # don't push what is available unmodified remotely
+    for asset_name, modification_status in candidates.items():
+        if modification_status == ModificationStatus.REMOTE_ONLY_AVAILABLE:
+            # don't push what is available unmodified remotely
             continue
 
         splits = asset_name.split("/")
@@ -1412,7 +1430,10 @@ def push(
             return 1
 
         logger.info(
-            "pushing %s/%s [%s]", TYPE_PLURAL[asset_type], asset_name, legend_symbol
+            "pushing %s/%s [%s]",
+            TYPE_PLURAL[asset_type],
+            asset_name,
+            modification_status,
         )
         storage = TYPE_STORAGE[asset_type](prefix, asset_name)
         data = storage.load()  # returns a named tuple
@@ -1445,7 +1466,9 @@ def push(
         url = "/api/v1/%s/%s/" % (TYPE_PLURAL[asset_type], webapi.user)
 
         # sends the data
-        if legend_symbol == "l":  # POST (new object)
+        if (
+            modification_status == ModificationStatus.LOCAL_ONLY_AVAILABLE
+        ):  # POST (new object)
             message["name"] = storage.name
 
             version = getattr(storage, "version")
@@ -1454,6 +1477,7 @@ def push(
 
             if asset_type == "experiment":
                 message["toolchain"] = "/".join(splits[1:-1])
+
             try:
                 webapi.post(url, data=message)
             except RuntimeError as e:
@@ -1465,7 +1489,7 @@ def push(
         else:  # PUT (update)
 
             url += "/".join(splits[1:]) + "/"
-            if legend_symbol == "d":
+            if modification_status == ModificationStatus.DOC_CHANGED:
                 data = {"description": message["description"]}
             else:
                 data = message