Avoid ENOENT in nilmdb.utils.diskusage.du

ENOENT might show up if we're actively deleting files in the nilmdb
thread while trying to read available space from e.g. the server
thread.

nilmdb/client/client.py

@@ -6,7 +6,6 @@ import nilmdb.utils
 import nilmdb.client.httpclient
 from nilmdb.client.errors import ClientError
 
-import re
 import time
 import simplejson as json
 import contextlib
@@ -66,12 +65,8 @@ class Client(object):
             params["layout"] = layout
         if extended:
             params["extended"] = 1
-        def sort_streams_nicely(x):
-            """Human-friendly sort (/stream/2 before /stream/10)"""
-            num = lambda t: int(t) if t.isdigit() else t
-            key = lambda k: [ num(c) for c in re.split('([0-9]+)', k[0]) ]
-            return sorted(x, key = key)
-        return sort_streams_nicely(self.http.get("stream/list", params))
+        streams = self.http.get("stream/list", params)
+        return nilmdb.utils.sort.sort_human(streams, key = lambda s: s[0])
 
     def stream_get_metadata(self, path, keys = None):
         params = { "path": path }
@@ -122,7 +117,10 @@ class Client(object):
             params["start"] = timestamp_to_string(start)
         if end is not None:
             params["end"] = timestamp_to_string(end)
-        return self.http.post("stream/remove", params)
+        total = 0
+        for count in self.http.post_gen("stream/remove", params):
+            total += int(count)
+        return total
 
     @contextlib.contextmanager
     def stream_insert_context(self, path, start = None, end = None):

nilmdb/client/httpclient.py

@@ -137,5 +137,14 @@ class HTTPClient(object):
         """Simple GET (parameters in URL) returning a generator"""
         return self._req_gen("GET", url, params, binary = binary)
 
+    def post_gen(self, url, params = None):
+        """Simple POST (parameters in body) returning a generator"""
+        if self.post_json:
+            return self._req_gen("POST", url, None,
+                                 json.dumps(params),
+                                 { 'Content-type': 'application/json' })
+        else:
+            return self._req_gen("POST", url, None, params)
+
     # Not much use for a POST or PUT generator, since they don't
     # return much data.

nilmdb/server/nilmdb.py

@@ -675,6 +675,7 @@ class NilmDB(object):
 
             # Count how many were removed
             removed += row_end - row_start
+            remaining -= row_end - row_start
 
             if restart is not None:
                 break

nilmdb/server/server.py

@@ -347,24 +347,34 @@ class Stream(NilmApp):
     # /stream/remove?path=/newton/prep&start=1234567890.0&end=1234567899.0
     @cherrypy.expose
     @cherrypy.tools.json_in()
-    @cherrypy.tools.json_out()
-    @exception_to_httperror(NilmDBError)
     @cherrypy.tools.CORS_allow(methods = ["POST"])
+    @chunked_response
+    @response_type("application/x-json-stream")
     def remove(self, path, start = None, end = None):
         """
         Remove data from the backend database.  Removes all data in
-        the interval [start, end).  Returns the number of data points
-        removed.
+        the interval [start, end).
+
+        Returns the number of data points removed.  Since this is a potentially
+        long-running operation, multiple numbers may be returned as the
+        data gets removed from the backend database.  The total number of
+        points removed is the sum of all of these numbers.
         """
         (start, end) = self._get_times(start, end)
-        total_removed = 0
-        while True:
-            (removed, restart) = self.db.stream_remove(path, start, end)
-            total_removed += removed
-            if restart is None:
-                break
-            start = restart
-        return total_removed
+
+        if len(self.db.stream_list(path = path)) != 1:
+            raise cherrypy.HTTPError("404", "No such stream: " + path)
+
+        @workaround_cp_bug_1200
+        def content(start, end):
+            # Note: disable chunked responses to see tracebacks from here.
+            while True:
+                (removed, restart) = self.db.stream_remove(path, start, end)
+                yield json.dumps(removed) + "\r\n"
+                if restart is None:
+                    break
+                start = restart
+        return content(start, end)
 
     # /stream/intervals?path=/newton/prep
     # /stream/intervals?path=/newton/prep&start=1234567890.0&end=1234567899.0

nilmdb/utils/__init__.py

@@ -13,3 +13,4 @@ import nilmdb.utils.time
 import nilmdb.utils.iterator
 import nilmdb.utils.interval
 import nilmdb.utils.lock
+import nilmdb.utils.sort

nilmdb/utils/diskusage.py

@@ -1,4 +1,5 @@
 import os
+import errno
 from math import log
 
 def human_size(num):
@@ -16,10 +17,17 @@ def human_size(num):
         return '1 byte'
 
 def du(path):
-    """Like du -sb, returns total size of path in bytes."""
-    size = os.path.getsize(path)
-    if os.path.isdir(path):
-        for thisfile in os.listdir(path):
-            filepath = os.path.join(path, thisfile)
-            size += du(filepath)
-    return size
+    """Like du -sb, returns total size of path in bytes.  Ignore
+    errors that might occur if we encounter broken symlinks or
+    files in the process of being removed."""
+    try:
+        size = os.path.getsize(path)
+        if os.path.isdir(path):
+            for thisfile in os.listdir(path):
+                filepath = os.path.join(path, thisfile)
+                size += du(filepath)
+        return size
+    except OSError as e: # pragma: no cover
+        if e.errno != errno.ENOENT:
+            raise
+        return 0

nilmdb/utils/sort.py

@@ -0,0 +1,18 @@
+import re
+
+def sort_human(items, key = None):
+    """Human-friendly sort (/stream/2 before /stream/10)"""
+    def to_num(val):
+        try:
+            return int(val)
+        except Exception:
+            return val
+
+    def human_key(text):
+        if key:
+            text = key(text)
+        # Break into character and numeric chunks.
+        chunks = re.split(r'([0-9]+)', text)
+        return [ to_num(c) for c in chunks ]
+
+    return sorted(items, key = human_key)

tests/test_client.py

@@ -105,16 +105,19 @@ class TestClient(object):
                 client.http.post("/stream/list")
         client = nilmdb.client.Client(url = testurl)
 
-        # Create three streams
+        # Create four streams
         client.stream_create("/newton/prep", "float32_8")
         client.stream_create("/newton/raw", "uint16_6")
-        client.stream_create("/newton/zzz/rawnotch", "uint16_9")
+        client.stream_create("/newton/zzz/rawnotch2", "uint16_9")
+        client.stream_create("/newton/zzz/rawnotch11", "uint16_9")
 
-        # Verify we got 3 streams
+        # Verify we got 4 streams in the right order
         eq_(client.stream_list(), [ ["/newton/prep", "float32_8"],
                                     ["/newton/raw", "uint16_6"],
-                                    ["/newton/zzz/rawnotch", "uint16_9"]
+                                    ["/newton/zzz/rawnotch2", "uint16_9"],
+                                    ["/newton/zzz/rawnotch11", "uint16_9"]
                                     ])
+
         # Match just one type or one path
         eq_(client.stream_list(layout="uint16_6"),
             [ ["/newton/raw", "uint16_6"] ])
@@ -327,6 +330,10 @@ class TestClient(object):
                      2525.169921875, 8350.83984375, 3724.699951171875,
                      1355.3399658203125, 2039.0))
 
+        # Just get some coverage
+        with assert_raises(ClientError) as e:
+            client.http.post("/stream/remove", { "path": "/none" })
+
         client.close()
 
     def test_client_06_generators(self):