dvc: remote: optimize imports

Decreases `time dvc --version` from ~1.4 sec to ~0.3 sec.

Related #2495
Related #2445

Signed-off-by: Ruslan Kuprieiev <[email protected]>

dvc/remote/azure.py

@@ -10,12 +10,6 @@
 
 from dvc.scheme import Schemes
 
-try:
-    from azure.storage.blob import BlockBlobService, BlobPermissions
-    from azure.common import AzureMissingResourceHttpError
-except ImportError:
-    BlockBlobService = None
-
 from dvc.utils.compat import urlparse
 from dvc.progress import Tqdm
 from dvc.config import Config
@@ -35,7 +29,7 @@ class RemoteAZURE(RemoteBASE):
         r"(ContainerName=(?P<container_name>[^;]+);?)?"
         r"(?P<connection_string>.+)?)?)$"
     )
-    REQUIRES = {"azure-storage-blob": BlockBlobService}
+    REQUIRES = {"azure-storage-blob": "azure.storage.blob"}
     PARAM_CHECKSUM = "etag"
     COPY_POLL_SECONDS = 5
 
@@ -72,6 +66,9 @@ def __init__(self, repo, config):
 
     @cached_property
     def blob_service(self):
+        from azure.storage.blob import BlockBlobService
+        from azure.common import AzureMissingResourceHttpError
+
         logger.debug("URL {}".format(self.path_info))
         logger.debug("Connection string {}".format(self.connection_string))
         blob_service = BlockBlobService(
@@ -139,6 +136,8 @@ def exists(self, path_info):
         return any(path_info.path == path for path in paths)
 
     def _generate_download_url(self, path_info, expires=3600):
+        from azure.storage.blob import BlobPermissions
+
         expires_at = datetime.utcnow() + timedelta(seconds=expires)
 
         sas_token = self.blob_service.generate_blob_shared_access_signature(

dvc/remote/base.py

@@ -86,31 +86,8 @@ class RemoteBASE(object):
 
     def __init__(self, repo, config):
         self.repo = repo
-        deps_ok = all(self.REQUIRES.values())
-        if not deps_ok:
-            missing = [k for k, v in self.REQUIRES.items() if v is None]
-            url = config.get(
-                Config.SECTION_REMOTE_URL, "{}://".format(self.scheme)
-            )
-            msg = (
-                "URL '{}' is supported but requires these missing "
-                "dependencies: {}. If you have installed dvc using pip, "
-                "choose one of these options to proceed: \n"
-                "\n"
-                "    1) Install specific missing dependencies:\n"
-                "        pip install {}\n"
-                "    2) Install dvc package that includes those missing "
-                "dependencies: \n"
-                "        pip install 'dvc[{}]'\n"
-                "    3) Install dvc package with all possible "
-                "dependencies included: \n"
-                "        pip install 'dvc[all]'\n"
-                "\n"
-                "If you have installed dvc from a binary package and you "
-                "are still seeing this message, please report it to us "
-                "using https://github.com/iterative/dvc/issues. Thank you!"
-            ).format(url, missing, " ".join(missing), self.scheme)
-            raise RemoteMissingDepsError(msg)
+
+        self._check_requires(config)
 
         core = config.get(Config.SECTION_CORE, {})
         self.checksum_jobs = core.get(
@@ -130,6 +107,43 @@ def __init__(self, repo, config):
             self.cache_types = copy(self.DEFAULT_CACHE_TYPES)
         self.cache_type_confirmed = False
 
+    def _check_requires(self, config):
+        import importlib
+
+        missing = []
+
+        for package, module in self.REQUIRES.items():
+            try:
+                importlib.import_module(module)
+            except ImportError:
+                missing.append(package)
+
+        if not missing:
+            return
+
+        url = config.get(
+            Config.SECTION_REMOTE_URL, "{}://".format(self.scheme)
+        )
+        msg = (
+            "URL '{}' is supported but requires these missing "
+            "dependencies: {}. If you have installed dvc using pip, "
+            "choose one of these options to proceed: \n"
+            "\n"
+            "    1) Install specific missing dependencies:\n"
+            "        pip install {}\n"
+            "    2) Install dvc package that includes those missing "
+            "dependencies: \n"
+            "        pip install 'dvc[{}]'\n"
+            "    3) Install dvc package with all possible "
+            "dependencies included: \n"
+            "        pip install 'dvc[all]'\n"
+            "\n"
+            "If you have installed dvc from a binary package and you "
+            "are still seeing this message, please report it to us "
+            "using https://github.com/iterative/dvc/issues. Thank you!"
+        ).format(url, missing, " ".join(missing), self.scheme)
+        raise RemoteMissingDepsError(msg)
+
     def __repr__(self):
         return "{class_name}: '{path_info}'".format(
             class_name=type(self).__name__,

dvc/remote/gs.py

@@ -5,11 +5,6 @@
 from funcy import cached_property
 from dvc.utils.compat import FileNotFoundError
 
-try:
-    from google.cloud import storage
-except ImportError:
-    storage = None
-
 from dvc.remote.base import RemoteBASE
 from dvc.config import Config
 from dvc.exceptions import DvcException
@@ -22,7 +17,7 @@
 class RemoteGS(RemoteBASE):
     scheme = Schemes.GS
     path_cls = CloudURLInfo
-    REQUIRES = {"google.cloud.storage": storage}
+    REQUIRES = {"google-cloud-storage": "google.cloud.storage"}
     PARAM_CHECKSUM = "md5"
 
     def __init__(self, repo, config):
@@ -37,10 +32,12 @@ def __init__(self, repo, config):
 
     @cached_property
     def gs(self):
+        from google.cloud.storage import Client
+
         return (
-            storage.Client.from_service_account_json(self.credentialpath)
+            Client.from_service_account_json(self.credentialpath)
             if self.credentialpath
-            else storage.Client(self.projectname)
+            else Client(self.projectname)
         )
 
     def get_file_checksum(self, path_info):

dvc/remote/hdfs.py

@@ -9,11 +9,6 @@
 from subprocess import Popen, PIPE
 from contextlib import contextmanager, closing
 
-try:
-    import pyarrow
-except ImportError:
-    pyarrow = None
-
 from dvc.config import Config
 from dvc.scheme import Schemes
 
@@ -30,7 +25,7 @@ class RemoteHDFS(RemoteBASE):
     scheme = Schemes.HDFS
     REGEX = r"^hdfs://((?P<user>.*)@)?.*$"
     PARAM_CHECKSUM = "checksum"
-    REQUIRES = {"pyarrow": pyarrow}
+    REQUIRES = {"pyarrow": "pyarrow"}
 
     def __init__(self, repo, config):
         super(RemoteHDFS, self).__init__(repo, config)
@@ -55,8 +50,9 @@ def __init__(self, repo, config):
             path=parsed.path,
         )
 
-    @staticmethod
-    def hdfs(path_info):
+    def hdfs(self, path_info):
+        import pyarrow
+
         return get_connection(
             pyarrow.hdfs.connect,
             path_info.host,

dvc/remote/oss.py

@@ -6,11 +6,6 @@
 
 from dvc.scheme import Schemes
 
-try:
-    import oss2
-except ImportError:
-    oss2 = None
-
 from dvc.config import Config
 from dvc.remote.base import RemoteBASE
 from dvc.progress import Tqdm
@@ -41,7 +36,7 @@ class RemoteOSS(RemoteBASE):
 
     scheme = Schemes.OSS
     path_cls = CloudURLInfo
-    REQUIRES = {"oss2": oss2}
+    REQUIRES = {"oss2": "oss2"}
     PARAM_CHECKSUM = "etag"
     COPY_POLL_SECONDS = 5
 
@@ -71,6 +66,8 @@ def __init__(self, repo, config):
 
     @property
     def oss_service(self):
+        import oss2
+
         if self._bucket is None:
             logger.debug("URL {}".format(self.path_info))
             logger.debug("key id {}".format(self.key_id))
@@ -98,6 +95,8 @@ def remove(self, path_info):
         self.oss_service.delete_object(path_info.path)
 
     def _list_paths(self, prefix):
+        import oss2
+
         for blob in oss2.ObjectIterator(self.oss_service, prefix=prefix):
             yield blob.key
 

dvc/remote/s3.py

@@ -4,11 +4,6 @@
 import logging
 from funcy import cached_property
 
-try:
-    import boto3
-except ImportError:
-    boto3 = None
-
 from dvc.progress import Tqdm
 from dvc.config import Config
 from dvc.remote.base import RemoteBASE
@@ -22,7 +17,7 @@
 class RemoteS3(RemoteBASE):
     scheme = Schemes.S3
     path_cls = CloudURLInfo
-    REQUIRES = {"boto3": boto3}
+    REQUIRES = {"boto3": "boto3"}
     PARAM_CHECKSUM = "etag"
 
     def __init__(self, repo, config):
@@ -61,6 +56,8 @@ def __init__(self, repo, config):
 
     @cached_property
     def s3(self):
+        import boto3
+
         session = boto3.session.Session(
             profile_name=self.profile, region_name=self.region
         )

dvc/remote/ssh/__init__.py

@@ -10,11 +10,6 @@
 from concurrent.futures import ThreadPoolExecutor
 from contextlib import contextmanager, closing
 
-try:
-    import paramiko
-except ImportError:
-    paramiko = None
-
 import dvc.prompt as prompt
 from dvc.config import Config
 from dvc.utils import to_chunks
@@ -33,7 +28,7 @@
 
 class RemoteSSH(RemoteBASE):
     scheme = Schemes.SSH
-    REQUIRES = {"paramiko": paramiko}
+    REQUIRES = {"paramiko": "paramiko"}
 
     JOBS = 4
     PARAM_CHECKSUM = "md5"
@@ -93,6 +88,8 @@ def ssh_config_filename():
 
     @staticmethod
     def _load_user_ssh_config(hostname):
+        import paramiko
+
         user_config_file = RemoteSSH.ssh_config_filename()
         user_ssh_config = {}
         if hostname and os.path.exists(user_config_file):

tests/unit/remote/test_base.py

@@ -10,8 +10,8 @@ class TestRemoteBASE(object):
 
 class TestMissingDeps(TestCase, TestRemoteBASE):
     def test(self):
-        REQUIRES = {"foo": None, "bar": None, "mock": mock}
-        with mock.patch.object(self.REMOTE_CLS, "REQUIRES", REQUIRES):
+        requires = {"missing": "missing"}
+        with mock.patch.object(self.REMOTE_CLS, "REQUIRES", requires):
             with self.assertRaises(RemoteMissingDepsError):
                 self.REMOTE_CLS(None, {})