api: add rev param to api calls

dvc/api.py

@@ -7,27 +7,27 @@
 except ImportError:
     from contextlib import GeneratorContextManager as GCM
 
-from dvc.utils import remove
 from dvc.utils.compat import urlparse
 from dvc.repo import Repo
 from dvc.external_repo import ExternalRepo
 
 
-def get_url(path, repo=None, remote=None):
+def get_url(path, repo=None, rev=None, remote=None):
     """Returns an url of a resource specified by path in repo"""
-    with _make_repo(repo) as _repo:
+    with _make_repo(repo, rev=rev) as _repo:
         abspath = os.path.join(_repo.root_dir, path)
         out, = _repo.find_outs_by_path(abspath)
         remote_obj = _repo.cloud.get_remote(remote)
         return str(remote_obj.checksum_to_path_info(out.checksum))
 
 
-def open(path, repo=None, remote=None, mode="r", encoding=None):
+def open(path, repo=None, rev=None, remote=None, mode="r", encoding=None):
     """Opens a specified resource as a file descriptor"""
     args = (path,)
     kwargs = {
         "repo": repo,
         "remote": remote,
+        "rev": rev,
         "mode": mode,
         "encoding": encoding,
     }
@@ -45,30 +45,33 @@ def __getattr__(self, name):
         )
 
 
-def _open(path, repo=None, remote=None, mode="r", encoding=None):
-    with _make_repo(repo) as _repo:
+def _open(path, repo=None, rev=None, remote=None, mode="r", encoding=None):
+    with _make_repo(repo, rev=rev) as _repo:
         abspath = os.path.join(_repo.root_dir, path)
         with _repo.open(
             abspath, remote=remote, mode=mode, encoding=encoding
         ) as fd:
             yield fd
 
 
-def read(path, repo=None, remote=None, mode="r", encoding=None):
+def read(path, repo=None, rev=None, remote=None, mode="r", encoding=None):
     """Read a specified resource into string"""
-    with open(path, repo, remote=remote, mode=mode, encoding=encoding) as fd:
+    with open(
+        path, repo=repo, rev=rev, remote=remote, mode=mode, encoding=encoding
+    ) as fd:
         return fd.read()
 
 
 @contextmanager
-def _make_repo(repo_url):
+def _make_repo(repo_url, rev=None):
     if not repo_url or urlparse(repo_url).scheme == "":
+        assert rev is None, "Custom revision is not supported for local repo"
         yield Repo(repo_url)
     else:
         tmp_dir = tempfile.mkdtemp("dvc-repo")
+        ext_repo = ExternalRepo(tmp_dir, url=repo_url, rev=rev)
         try:
-            ext_repo = ExternalRepo(tmp_dir, url=repo_url)
             ext_repo.install()
             yield ext_repo.repo
         finally:
-            remove(tmp_dir)
+            ext_repo.uninstall()

dvc/exceptions.py

@@ -263,3 +263,10 @@ def __init__(self, etag, cached_etag):
             "ETag mismatch detected when copying file to cache! "
             "(expected: '{}', actual: '{}')".format(etag, cached_etag)
         )
+
+
+class OutputFileMissingError(DvcException):
+    def __init__(self, path):
+        super(OutputFileMissingError, self).__init__(
+            "Can't find {} neither locally nor on remote".format(path)
+        )

dvc/external_repo.py

@@ -5,7 +5,7 @@
 import logging
 import shortuuid
 
-from funcy import cached_property
+from funcy import cached_property, retry
 from schema import Optional
 
 from dvc.config import Config
@@ -138,7 +138,16 @@ def uninstall(self):
             )
             return
 
-        remove(self.path)
+        # If repo has been initialized then we need to close its git repo
+        if "repo" in self.__dict__:
+            self.repo.scm.git.close()
+
+        if os.name == "nt":
+            # git.exe may hang for a while not permitting to remove temp dir
+            os_retry = retry(5, errors=OSError, timeout=0.1)
+            os_retry(remove)(self.path)
+        else:
+            remove(self.path)
 
     def update(self):
         self.repo.scm.fetch(self.rev)

dvc/repo/__init__.py

@@ -8,10 +8,11 @@
     NotDvcRepoError,
     OutputNotFoundError,
     TargetNotDirectoryError,
+    OutputFileMissingError,
 )
 from dvc.ignore import DvcIgnoreFileHandler
 from dvc.path_info import PathInfo
-from dvc.utils.compat import open as _open
+from dvc.utils.compat import open as _open, fspath_py35
 from dvc.utils import relpath
 
 logger = logging.getLogger(__name__)
@@ -455,9 +456,15 @@ def open(self, path, remote=None, mode="r", encoding=None):
         if out.isdir():
             raise ValueError("Can't open a dir")
 
+        cache_file = self.cache.local.checksum_to_path_info(out.checksum)
+        cache_file = fspath_py35(cache_file)
+
         with self.state:
             cache_info = out.get_used_cache(remote=remote)
             self.cloud.pull(cache_info, remote=remote)
 
-        cache_file = self.cache.local.checksum_to_path_info(out.checksum)
-        return _open(cache_file.fspath, mode=mode, encoding=encoding)
+        # Since pull may just skip with a warning, we need to check it here
+        if not os.path.exists(cache_file):
+            raise OutputFileMissingError(relpath(path, self.root_dir))
+
+        return _open(cache_file, mode=mode, encoding=encoding)

dvc/repo/get.py

@@ -5,7 +5,6 @@
 from dvc.path_info import PathInfo
 from dvc.external_repo import ExternalRepo
 from dvc.utils.compat import urlparse
-from dvc.utils import remove
 
 
 @staticmethod
@@ -19,8 +18,8 @@ def get(url, path, out=None, rev=None):
     # and won't work with reflink/hardlink.
     dpath = os.path.dirname(os.path.abspath(out))
     tmp_dir = os.path.join(dpath, "." + str(shortuuid.uuid()))
+    erepo = ExternalRepo(tmp_dir, url=url, rev=rev)
     try:
-        erepo = ExternalRepo(tmp_dir, url=url, rev=rev)
         erepo.install()
         # Try any links possible to avoid data duplication.
         #
@@ -42,7 +41,5 @@ def get(url, path, out=None, rev=None):
         o.path_info = PathInfo(os.path.abspath(out))
         with o.repo.state:
             o.checkout()
-        erepo.repo.scm.git.close()
     finally:
-        if os.path.exists(tmp_dir):
-            remove(tmp_dir)
+        erepo.uninstall()

tests/func/test_api.py

@@ -2,6 +2,7 @@
 import shutil
 
 from dvc import api
+from dvc.exceptions import OutputFileMissingError
 from dvc.main import main
 from dvc.path_info import URLInfo
 from dvc.remote.config import RemoteConfig
@@ -101,16 +102,31 @@ def test_open(repo_dir, dvc_repo, remote_url):
 
 
 def test_open_external(repo_dir, dvc_repo, erepo, remote_url):
+    erepo.dvc.scm.checkout("branch")
     _set_remote_url_and_commit(erepo.dvc, remote_url)
-    erepo.dvc.push()
+    erepo.dvc.scm.checkout("master")
+    _set_remote_url_and_commit(erepo.dvc, remote_url)
+
+    erepo.dvc.push(all_branches=True)
 
     # Remove cache to force download
     shutil.rmtree(erepo.dvc.cache.local.cache_dir)
 
     # Using file url to force clone to tmp repo
     repo_url = "file://" + erepo.dvc.root_dir
-    with api.open(repo_dir.FOO, repo=repo_url) as fd:
-        assert fd.read() == repo_dir.FOO_CONTENTS
+    with api.open("version", repo=repo_url) as fd:
+        assert fd.read() == "master"
+
+    assert api.read("version", repo=repo_url, rev="branch") == "branch"
+
+
+def test_open_missing(erepo):
+    # Remove cache to make foo missing
+    shutil.rmtree(erepo.dvc.cache.local.cache_dir)
+
+    repo_url = "file://" + erepo.dvc.root_dir
+    with pytest.raises(OutputFileMissingError):
+        api.read(erepo.FOO, repo=repo_url)
 
 
 def _set_remote_url_and_commit(repo, remote_url):