Merge branch 'master' into 4232-slow-pipes-n-jobs
[arvados.git] / sdk / python / arvados / collection.py
index 3a90d6d3b0fb64d2ff49f4262b6e6c5ff3924cc9..7bfdf782f8d06b03d6ac482fa64872d1eb8ff9be 100644 (file)
@@ -1,28 +1,14 @@
-import gflags
-import httplib
-import httplib2
+import functools
 import logging
 import os
-import pprint
-import sys
-import types
-import subprocess
-import json
-import UserDict
 import re
-import hashlib
-import string
-import bz2
-import zlib
-import fcntl
-import time
-import threading
 
 from collections import deque
 from stat import *
 
+from .arvfile import ArvadosFileBase
 from keep import *
-from stream import *
+from .stream import StreamReader, split
 import config
 import errors
 import util
@@ -71,9 +57,9 @@ def normalize_stream(s, stream):
 
 class CollectionBase(object):
     def __enter__(self):
-        pass
+        return self
 
-    def __exit__(self):
+    def __exit__(self, exc_type, exc_value, traceback):
         pass
 
     def _my_keep(self):
@@ -139,6 +125,7 @@ class CollectionReader(CollectionBase):
         else:
             raise errors.ArgumentError(
                 "Argument to CollectionReader must be a manifest or a collection UUID")
+        self._api_response = None
         self._streams = None
 
     def _populate_from_api_server(self):
@@ -153,10 +140,10 @@ class CollectionReader(CollectionBase):
             if self._api_client is None:
                 self._api_client = arvados.api('v1')
                 self._keep_client = None  # Make a new one with the new api.
-            c = self._api_client.collections().get(
+            self._api_response = self._api_client.collections().get(
                 uuid=self._manifest_locator).execute(
                 num_retries=self.num_retries)
-            self._manifest_text = c['manifest_text']
+            self._manifest_text = self._api_response['manifest_text']
             return None
         except Exception as e:
             return e
@@ -173,26 +160,24 @@ class CollectionReader(CollectionBase):
             return e
 
     def _populate(self):
-        if self._streams is not None:
-            return
         error_via_api = None
         error_via_keep = None
-        should_try_keep = (not self._manifest_text and
+        should_try_keep = ((self._manifest_text is None) and
                            util.keep_locator_pattern.match(
                 self._manifest_locator))
-        if (not self._manifest_text and
+        if ((self._manifest_text is None) and
             util.signed_locator_pattern.match(self._manifest_locator)):
             error_via_keep = self._populate_from_keep()
-        if not self._manifest_text:
+        if self._manifest_text is None:
             error_via_api = self._populate_from_api_server()
             if error_via_api is not None and not should_try_keep:
                 raise error_via_api
-        if (not self._manifest_text and
+        if ((self._manifest_text is None) and
             not error_via_keep and
             should_try_keep):
             # Looks like a keep locator, and we didn't already try keep above
             error_via_keep = self._populate_from_keep()
-        if not self._manifest_text:
+        if self._manifest_text is None:
             # Nothing worked!
             raise arvados.errors.NotFoundError(
                 ("Failed to retrieve collection '{}' " +
@@ -205,17 +190,32 @@ class CollectionReader(CollectionBase):
                          for sline in self._manifest_text.split("\n")
                          if sline]
 
-    def normalize(self):
-        self._populate()
+    def _populate_first(orig_func):
+        # Decorator for methods that read actual Collection data.
+        @functools.wraps(orig_func)
+        def wrapper(self, *args, **kwargs):
+            if self._streams is None:
+                self._populate()
+            return orig_func(self, *args, **kwargs)
+        return wrapper
+
+    @_populate_first
+    def api_response(self):
+        """api_response() -> dict or None
+
+        Returns information about this Collection fetched from the API server.
+        If the Collection exists in Keep but not the API server, currently
+        returns None.  Future versions may provide a synthetic response.
+        """
+        return self._api_response
 
+    @_populate_first
+    def normalize(self):
         # Rearrange streams
         streams = {}
         for s in self.all_streams():
             for f in s.all_files():
-                filestream = s.name() + "/" + f.name()
-                r = filestream.rindex("/")
-                streamname = filestream[:r]
-                filename = filestream[r+1:]
+                streamname, filename = split(s.name() + "/" + f.name())
                 if streamname not in streams:
                     streams[streamname] = {}
                 if filename not in streams[streamname]:
@@ -231,8 +231,33 @@ class CollectionReader(CollectionBase):
             [StreamReader(stream, keep=self._my_keep()).manifest_text()
              for stream in self._streams])
 
+    @_populate_first
+    def open(self, streampath, filename=None):
+        """open(streampath[, filename]) -> file-like object
+
+        Pass in the path of a file to read from the Collection, either as a
+        single string or as two separate stream name and file name arguments.
+        This method returns a file-like object to read that file.
+        """
+        if filename is None:
+            streampath, filename = split(streampath)
+        keep_client = self._my_keep()
+        for stream_s in self._streams:
+            stream = StreamReader(stream_s, keep_client,
+                                  num_retries=self.num_retries)
+            if stream.name() == streampath:
+                break
+        else:
+            raise ValueError("stream '{}' not found in Collection".
+                             format(streampath))
+        try:
+            return stream.files()[filename]
+        except KeyError:
+            raise ValueError("file '{}' not found in Collection stream '{}'".
+                             format(filename, streampath))
+
+    @_populate_first
     def all_streams(self):
-        self._populate()
         return [StreamReader(s, self._my_keep(), num_retries=self.num_retries)
                 for s in self._streams]
 
@@ -241,6 +266,7 @@ class CollectionReader(CollectionBase):
             for f in s.all_files():
                 yield f
 
+    @_populate_first
     def manifest_text(self, strip=False, normalize=False):
         if normalize:
             cr = CollectionReader(self.manifest_text())
@@ -249,14 +275,36 @@ class CollectionReader(CollectionBase):
         elif strip:
             return self.stripped_manifest()
         else:
-            self._populate()
             return self._manifest_text
 
 
+class _WriterFile(ArvadosFileBase):
+    def __init__(self, coll_writer, name):
+        super(_WriterFile, self).__init__(name, 'wb')
+        self.dest = coll_writer
+
+    def close(self):
+        super(_WriterFile, self).close()
+        self.dest.finish_current_file()
+
+    @ArvadosFileBase._before_close
+    def write(self, data):
+        self.dest.write(data)
+
+    @ArvadosFileBase._before_close
+    def writelines(self, seq):
+        for data in seq:
+            self.write(data)
+
+    @ArvadosFileBase._before_close
+    def flush(self):
+        self.dest.flush_data()
+
+
 class CollectionWriter(CollectionBase):
     KEEP_BLOCK_SIZE = 2**26
 
-    def __init__(self, api_client=None, num_retries=0):
+    def __init__(self, api_client=None, num_retries=0, replication=None):
         """Instantiate a CollectionWriter.
 
         CollectionWriter lets you build a new Arvados Collection from scratch.
@@ -272,9 +320,13 @@ class CollectionWriter(CollectionBase):
           service requests.  Default 0.  You may change this value
           after instantiation, but note those changes may not
           propagate to related objects like the Keep client.
+        * replication: The number of copies of each block to store.
+          If this argument is None or not supplied, replication is
+          the server-provided default if available, otherwise 2.
         """
         self._api_client = api_client
         self.num_retries = num_retries
+        self.replication = (2 if replication is None else replication)
         self._keep_client = None
         self._data_buffer = []
         self._data_buffer_len = 0
@@ -289,9 +341,11 @@ class CollectionWriter(CollectionBase):
         self._queued_file = None
         self._queued_dirents = deque()
         self._queued_trees = deque()
+        self._last_open = None
 
-    def __exit__(self):
-        self.finish()
+    def __exit__(self, exc_type, exc_value, traceback):
+        if exc_type is None:
+            self.finish()
 
     def do_queued_work(self):
         # The work queue consists of three pieces:
@@ -394,11 +448,42 @@ class CollectionWriter(CollectionBase):
         while self._data_buffer_len >= self.KEEP_BLOCK_SIZE:
             self.flush_data()
 
+    def open(self, streampath, filename=None):
+        """open(streampath[, filename]) -> file-like object
+
+        Pass in the path of a file to write to the Collection, either as a
+        single string or as two separate stream name and file name arguments.
+        This method returns a file-like object you can write to add it to the
+        Collection.
+
+        You may only have one file object from the Collection open at a time,
+        so be sure to close the object when you're done.  Using the object in
+        a with statement makes that easy::
+
+          with cwriter.open('./doc/page1.txt') as outfile:
+              outfile.write(page1_data)
+          with cwriter.open('./doc/page2.txt') as outfile:
+              outfile.write(page2_data)
+        """
+        if filename is None:
+            streampath, filename = split(streampath)
+        if self._last_open and not self._last_open.closed:
+            raise errors.AssertionError(
+                "can't open '{}' when '{}' is still open".format(
+                    filename, self._last_open.name))
+        if streampath != self.current_stream_name():
+            self.start_new_stream(streampath)
+        self.set_current_file_name(filename)
+        self._last_open = _WriterFile(self, filename)
+        return self._last_open
+
     def flush_data(self):
         data_buffer = ''.join(self._data_buffer)
         if data_buffer:
             self._current_stream_locators.append(
-                self._my_keep().put(data_buffer[0:self.KEEP_BLOCK_SIZE]))
+                self._my_keep().put(
+                    data_buffer[0:self.KEEP_BLOCK_SIZE],
+                    copies=self.replication))
             self._data_buffer = [data_buffer[self.KEEP_BLOCK_SIZE:]]
             self._data_buffer_len = len(self._data_buffer[0])
 
@@ -411,6 +496,10 @@ class CollectionWriter(CollectionBase):
             raise errors.AssertionError(
                 "Manifest filenames cannot contain whitespace: %s" %
                 newfilename)
+        elif re.search(r'\x00', newfilename):
+            raise errors.AssertionError(
+                "Manifest filenames cannot contain NUL characters: %s" %
+                newfilename)
         self._current_file_name = newfilename
 
     def current_file_name(self):
@@ -469,8 +558,16 @@ class CollectionWriter(CollectionBase):
         self._current_file_name = None
 
     def finish(self):
-        # Store the manifest in Keep and return its locator.
-        return self._my_keep().put(self.manifest_text())
+        """Store the manifest in Keep and return its locator.
+
+        This is useful for storing manifest fragments (task outputs)
+        temporarily in Keep during a Crunch job.
+
+        In other cases you should make a collection instead, by
+        sending manifest_text() to the API server's "create
+        collection" endpoint.
+        """
+        return self._my_keep().put(self.manifest_text(), copies=self.replication)
 
     def portable_data_hash(self):
         stripped = self.stripped_manifest()
@@ -504,10 +601,9 @@ class ResumableCollectionWriter(CollectionWriter):
                    '_data_buffer', '_dependencies', '_finished_streams',
                    '_queued_dirents', '_queued_trees']
 
-    def __init__(self, api_client=None, num_retries=0):
+    def __init__(self, api_client=None, **kwargs):
         self._dependencies = {}
-        super(ResumableCollectionWriter, self).__init__(
-            api_client, num_retries=num_retries)
+        super(ResumableCollectionWriter, self).__init__(api_client, **kwargs)
 
     @classmethod
     def from_state(cls, state, *init_args, **init_kwargs):