From 126e0e78ff99161c2e76e5c8eb0c3850a32eaf35 Mon Sep 17 00:00:00 2001
From: Peter Yu <2057325+yukw777@users.noreply.github.com>
Date: Wed, 29 Apr 2020 14:11:16 -0400
Subject: [PATCH 01/18] allow loading checkpoints from urls

---
 pytorch_lightning/core/saving.py         |  5 +++--
 pytorch_lightning/trainer/training_io.py |  3 ++-
 pytorch_lightning/utilities/io.py        | 11 +++++++++++
 3 files changed, 16 insertions(+), 3 deletions(-)
 create mode 100644 pytorch_lightning/utilities/io.py

diff --git a/pytorch_lightning/core/saving.py b/pytorch_lightning/core/saving.py
index 1e399ff2ecfc4..3fcf982457bd3 100644
--- a/pytorch_lightning/core/saving.py
+++ b/pytorch_lightning/core/saving.py
@@ -10,6 +10,7 @@
 
 from pytorch_lightning import _logger as log
 from pytorch_lightning.utilities import rank_zero_warn, AttributeDict
+from pytorch_lightning.utilities.io import load as pl_load
 
 PRIMITIVE_TYPES = (bool, int, float, str)
 ALLOWED_CONFIG_TYPES = (AttributeDict, dict, Namespace)
@@ -131,9 +132,9 @@ def load_from_checkpoint(
                 y_hat = pretrained_model(x)
         """
         if map_location is not None:
-            checkpoint = torch.load(checkpoint_path, map_location=map_location)
+            checkpoint = pl_load(checkpoint_path, map_location=map_location)
         else:
-            checkpoint = torch.load(checkpoint_path, map_location=lambda storage, loc: storage)
+            checkpoint = pl_load(checkpoint_path, map_location=lambda storage, loc: storage)
 
         # add the hparams from csv file to checkpoint
         if tags_csv is not None:
diff --git a/pytorch_lightning/trainer/training_io.py b/pytorch_lightning/trainer/training_io.py
index bd3d312a86882..7c6d429a980b6 100644
--- a/pytorch_lightning/trainer/training_io.py
+++ b/pytorch_lightning/trainer/training_io.py
@@ -102,6 +102,7 @@
     LightningDataParallel,
 )
 from pytorch_lightning.utilities import rank_zero_warn, parsing
+from pytorch_lightning.utilities.io import load as pl_load
 
 try:
     import torch_xla
@@ -287,7 +288,7 @@ def restore(self, checkpoint_path: str, on_gpu: bool):
         #     checkpoint = torch.load(checkpoint_path)
         # else:
         # load on CPU first
-        checkpoint = torch.load(checkpoint_path, map_location=lambda storage, loc: storage)
+        checkpoint = pl_load(checkpoint_path, map_location=lambda storage, loc: storage)
 
         # load model state
         model = self.get_model()
diff --git a/pytorch_lightning/utilities/io.py b/pytorch_lightning/utilities/io.py
new file mode 100644
index 0000000000000..f9d5112505cc4
--- /dev/null
+++ b/pytorch_lightning/utilities/io.py
@@ -0,0 +1,11 @@
+import torch
+
+from urllib.parse import urlparse
+
+
+def load(path_or_url: str, map_location):
+    parsed = urlparse(path_or_url)
+    if parsed.scheme == '':
+        # local file
+        return torch.load(path_or_url, map_location=map_location)
+    return torch.hub.load_state_dict_from_url(path_or_url, map_location=map_location)

From 08fb93e5182ab98933f8be6ff32c119f5581982e Mon Sep 17 00:00:00 2001
From: Peter Yu <2057325+yukw777@users.noreply.github.com>
Date: Sat, 30 May 2020 17:14:56 -0400
Subject: [PATCH 02/18] tmpdir_server fixture

---
 tests/conftest.py | 33 ++++++++++++++++++++++++++++++++-
 1 file changed, 32 insertions(+), 1 deletion(-)

diff --git a/tests/conftest.py b/tests/conftest.py
index 8eb3444ddaaba..935b206b1da6a 100644
--- a/tests/conftest.py
+++ b/tests/conftest.py
@@ -1,5 +1,7 @@
-from functools import wraps
+from functools import wraps, partial
+from http.server import SimpleHTTPRequestHandler, HTTPServer
 
+import sys
 import pytest
 import torch.multiprocessing as mp
 
@@ -17,3 +19,32 @@ def pytest_pyfunc_call(pyfuncitem):
 
         mp.spawn(wraps, (testfunction, testargs))
         return True
+
+
+def run_file_server(dir):
+    if sys.version_info >= (3, 7):
+        Handler = partial(SimpleHTTPRequestHandler, directory=dir)
+    else:
+        # unfortunately SimpleHTTPRequestHandler doesn't accept the directory arg in python3.6
+        # so we have to hack it like this
+        import os
+
+        class Handler(SimpleHTTPRequestHandler):
+            def translate_path(self, path):
+                # get the path from cwd
+                path = super().translate_path(path)
+                # get the relative path
+                relpath = os.path.relpath(path, os.getcwd())
+                # return the full path from dir
+                return os.path.join(dir, relpath)
+
+    with HTTPServer(('', 8000), Handler) as httpd:
+        httpd.serve_forever()
+
+
+@pytest.fixture
+def tmpdir_server(tmpdir):
+    p = mp.Process(target=run_file_server, args=(str(tmpdir),))
+    p.start()
+    yield
+    p.terminate()

From 50cb6d9bf3aeea4eb9329946675d49d6d99b7433 Mon Sep 17 00:00:00 2001
From: Peter Yu <2057325+yukw777@users.noreply.github.com>
Date: Sat, 30 May 2020 17:18:44 -0400
Subject: [PATCH 03/18] test cases for loading checkpoints from url

---
 tests/trainer/test_trainer.py | 18 ++++++++++++++++--
 1 file changed, 16 insertions(+), 2 deletions(-)

diff --git a/tests/trainer/test_trainer.py b/tests/trainer/test_trainer.py
index bf4c8198e3db7..cedef1bfd68cd 100644
--- a/tests/trainer/test_trainer.py
+++ b/tests/trainer/test_trainer.py
@@ -20,7 +20,7 @@
 from tests.base import EvalModelTemplate
 
 
-def test_no_val_module(tmpdir):
+def test_no_val_module(tmpdir, tmpdir_server):
     """Tests use case where trainer saves the model, and user loads it from tags independently."""
 
     model = EvalModelTemplate()
@@ -55,8 +55,15 @@ def test_no_val_module(tmpdir):
     )
     model_2.eval()
 
+    # load new model from url
+    model_3 = EvalModelTemplate.load_from_checkpoint(
+        checkpoint_path='http://localhost:8000/save_test.ckpt',
+        hparams_file=hparams_path
+    )
+    model_3.eval()
+
 
-def test_no_val_end_module(tmpdir):
+def test_no_val_end_module(tmpdir, tmpdir_server):
     """Tests use case where trainer saves the model, and user loads it from tags independently."""
 
     model = EvalModelTemplate()
@@ -88,6 +95,13 @@ def test_no_val_end_module(tmpdir):
     )
     model_2.eval()
 
+    # load new model from url
+    model_3 = EvalModelTemplate.load_from_checkpoint(
+        checkpoint_path='http://localhost:8000/save_test.ckpt',
+        hparams_file=hparams_path
+    )
+    model_3.eval()
+
 
 def test_gradient_accumulation_scheduling(tmpdir):
     """

From 20166d95bcf3b296127d5ab7a3fc2e311ad0d642 Mon Sep 17 00:00:00 2001
From: Peter Yu <2057325+yukw777@users.noreply.github.com>
Date: Sat, 30 May 2020 17:20:43 -0400
Subject: [PATCH 04/18] dir => root_dir

---
 tests/conftest.py | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/tests/conftest.py b/tests/conftest.py
index 935b206b1da6a..40cf42ce0b1c4 100644
--- a/tests/conftest.py
+++ b/tests/conftest.py
@@ -21,9 +21,9 @@ def pytest_pyfunc_call(pyfuncitem):
         return True
 
 
-def run_file_server(dir):
+def run_file_server(root_dir):
     if sys.version_info >= (3, 7):
-        Handler = partial(SimpleHTTPRequestHandler, directory=dir)
+        Handler = partial(SimpleHTTPRequestHandler, directory=root_dir)
     else:
         # unfortunately SimpleHTTPRequestHandler doesn't accept the directory arg in python3.6
         # so we have to hack it like this
@@ -35,8 +35,8 @@ def translate_path(self, path):
                 path = super().translate_path(path)
                 # get the relative path
                 relpath = os.path.relpath(path, os.getcwd())
-                # return the full path from dir
-                return os.path.join(dir, relpath)
+                # return the full path from root_dir
+                return os.path.join(root_dir, relpath)
 
     with HTTPServer(('', 8000), Handler) as httpd:
         httpd.serve_forever()

From db7126355978ff0bd6da569a6de719010d638952 Mon Sep 17 00:00:00 2001
From: Peter Yu <2057325+yukw777@users.noreply.github.com>
Date: Sat, 30 May 2020 17:31:22 -0400
Subject: [PATCH 05/18] default map_location to None

---
 pytorch_lightning/utilities/io.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pytorch_lightning/utilities/io.py b/pytorch_lightning/utilities/io.py
index f9d5112505cc4..b2f9ffa788541 100644
--- a/pytorch_lightning/utilities/io.py
+++ b/pytorch_lightning/utilities/io.py
@@ -3,7 +3,7 @@
 from urllib.parse import urlparse
 
 
-def load(path_or_url: str, map_location):
+def load(path_or_url: str, map_location=None):
     parsed = urlparse(path_or_url)
     if parsed.scheme == '':
         # local file

From 03844be8ab5eba892a36256571bf3f7c25327e9c Mon Sep 17 00:00:00 2001
From: Peter Yu <2057325+yukw777@users.noreply.github.com>
Date: Sat, 30 May 2020 17:31:52 -0400
Subject: [PATCH 06/18] test case for resume_from_checkpoint

---
 tests/trainer/test_trainer.py | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/tests/trainer/test_trainer.py b/tests/trainer/test_trainer.py
index cedef1bfd68cd..9d31211438304 100644
--- a/tests/trainer/test_trainer.py
+++ b/tests/trainer/test_trainer.py
@@ -16,6 +16,7 @@
 from pytorch_lightning.core.saving import load_hparams_from_tags_csv, load_hparams_from_yaml, save_hparams_to_tags_csv
 from pytorch_lightning.loggers import TensorBoardLogger
 from pytorch_lightning.trainer.logging import TrainerLoggingMixin
+from pytorch_lightning.utilities.io import load as pl_load
 from pytorch_lightning.utilities.exceptions import MisconfigurationException
 from tests.base import EvalModelTemplate
 
@@ -334,7 +335,7 @@ def test_model_freeze_unfreeze():
     model.unfreeze()
 
 
-def test_resume_from_checkpoint_epoch_restored(tmpdir):
+def test_resume_from_checkpoint_epoch_restored(tmpdir, tmpdir_server):
     """Verify resuming from checkpoint runs the right number of epochs"""
 
     hparams = EvalModelTemplate.get_default_hparams()
@@ -387,10 +388,12 @@ def increment_on_load_checkpoint(self, _):
 
     # Other checkpoints can be uncommented if/when resuming mid-epoch is supported
     checkpoints = sorted(glob.glob(os.path.join(trainer.checkpoint_callback.dirpath, '*.ckpt')))
+    # add some url checkpoints
+    checkpoints += ['http://localhost:8000/' + os.path.basename(check) for check in checkpoints]
 
     for check in checkpoints:
         next_model = _new_model()
-        state = torch.load(check)
+        state = pl_load(check)
 
         # Resume training
         trainer_options['max_epochs'] = 2

From 99cf5803e1a77a49c26686ddaa58c019e9c58808 Mon Sep 17 00:00:00 2001
From: Peter Yu <2057325+yukw777@users.noreply.github.com>
Date: Sat, 30 May 2020 17:33:58 -0400
Subject: [PATCH 07/18] changelog

---
 CHANGELOG.md | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 80070aeb3dde6..2f8eb14a83f10 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -34,6 +34,8 @@ The format is based on [Keep a Changelog](http://keepachangelog.com/en/1.0.0/).
 - Added [black](https://black.readthedocs.io/en/stable/) formatter for the code with code-checker on pull ([1610](https://github.com/PyTorchLightning/pytorch-lightning/pull/1610))
 - Added back the slow spawn ddp implementation as `ddp_spawn` ([#2115](https://github.com/PyTorchLightning/pytorch-lightning/pull/2115))
 
+- Added loading checkpoings from URLs ([#1532](https://github.com/PyTorchLightning/pytorch-lightning/issues/1532))
+
 ### Changed
 
 - Allow user to select individual TPU core to train on ([#1729](https://github.com/PyTorchLightning/pytorch-lightning/pull/1729))

From e10befd4d15e22ee30d464ebfedd926c46a3f5ab Mon Sep 17 00:00:00 2001
From: Peter Yu <2057325+yukw777@users.noreply.github.com>
Date: Sat, 30 May 2020 17:39:01 -0400
Subject: [PATCH 08/18] doc update

---
 pytorch_lightning/core/saving.py     | 3 +--
 pytorch_lightning/trainer/trainer.py | 1 +
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/pytorch_lightning/core/saving.py b/pytorch_lightning/core/saving.py
index 3fcf982457bd3..092424f870d90 100644
--- a/pytorch_lightning/core/saving.py
+++ b/pytorch_lightning/core/saving.py
@@ -56,7 +56,7 @@ def load_from_checkpoint(
         Any arguments specified through \*args and \*\*kwargs will override args stored in `module_arguments`.
 
         Args:
-            checkpoint_path: Path to checkpoint.
+            checkpoint_path: Path to checkpoint. This can also be a URL.
             args: Any positional args needed to init the model.
             map_location:
                 If your checkpoint saved a GPU model and you now load on CPUs
@@ -163,7 +163,6 @@ def load_from_checkpoint(
 
     @classmethod
     def _load_model_state(cls, checkpoint: Dict[str, Any], *args, **kwargs):
-
         # pass in the values we saved automatically
         if cls.CHECKPOINT_KEY_HYPER_PARAMS in checkpoint:
             # todo add some back compatibility
diff --git a/pytorch_lightning/trainer/trainer.py b/pytorch_lightning/trainer/trainer.py
index 1cf216eac345d..0fb76acd1a700 100644
--- a/pytorch_lightning/trainer/trainer.py
+++ b/pytorch_lightning/trainer/trainer.py
@@ -279,6 +279,7 @@ def __init__(
             truncated_bptt_steps: Truncated back prop breaks performs backprop every k steps of
 
             resume_from_checkpoint: To resume training from a specific checkpoint pass in the path here.
+                This can be a URL.
 
             profiler:  To profile individual steps during training and assist in
 

From 2e7d93397dbf48e394f4646902e4359e36a6009f Mon Sep 17 00:00:00 2001
From: Peter Yu <2057325+yukw777@users.noreply.github.com>
Date: Sun, 31 May 2020 11:31:11 -0400
Subject: [PATCH 09/18] monkeypatch TORCH_HOME to avoid caching

---
 tests/trainer/test_trainer.py | 12 +++++++++---
 1 file changed, 9 insertions(+), 3 deletions(-)

diff --git a/tests/trainer/test_trainer.py b/tests/trainer/test_trainer.py
index 9d31211438304..78b6a543779b2 100644
--- a/tests/trainer/test_trainer.py
+++ b/tests/trainer/test_trainer.py
@@ -21,8 +21,10 @@
 from tests.base import EvalModelTemplate
 
 
-def test_no_val_module(tmpdir, tmpdir_server):
+def test_no_val_module(monkeypatch, tmpdir, tmpdir_server):
     """Tests use case where trainer saves the model, and user loads it from tags independently."""
+    # set $TORCH_HOME, which determines torch hub's cache path, to tmpdir
+    monkeypatch.setenv('TORCH_HOME', tmpdir)
 
     model = EvalModelTemplate()
 
@@ -64,8 +66,10 @@ def test_no_val_module(tmpdir, tmpdir_server):
     model_3.eval()
 
 
-def test_no_val_end_module(tmpdir, tmpdir_server):
+def test_no_val_end_module(monkeypatch, tmpdir, tmpdir_server):
     """Tests use case where trainer saves the model, and user loads it from tags independently."""
+    # set $TORCH_HOME, which determines torch hub's cache path, to tmpdir
+    monkeypatch.setenv('TORCH_HOME', tmpdir)
 
     model = EvalModelTemplate()
 
@@ -335,8 +339,10 @@ def test_model_freeze_unfreeze():
     model.unfreeze()
 
 
-def test_resume_from_checkpoint_epoch_restored(tmpdir, tmpdir_server):
+def test_resume_from_checkpoint_epoch_restored(monkeypatch, tmpdir, tmpdir_server):
     """Verify resuming from checkpoint runs the right number of epochs"""
+    # set $TORCH_HOME, which determines torch hub's cache path, to tmpdir
+    monkeypatch.setenv('TORCH_HOME', tmpdir)
 
     hparams = EvalModelTemplate.get_default_hparams()
 

From 09fb74cbc4a25fcba8fd78aa6e216a85e75cb454 Mon Sep 17 00:00:00 2001
From: Peter Yu <2057325+yukw777@users.noreply.github.com>
Date: Sun, 31 May 2020 13:16:08 -0400
Subject: [PATCH 10/18] Use a threading server with random ports so that it is
 easier to clean up

---
 tests/conftest.py | 29 ++++++++++++++---------------
 1 file changed, 14 insertions(+), 15 deletions(-)

diff --git a/tests/conftest.py b/tests/conftest.py
index 40cf42ce0b1c4..627a7837e376e 100644
--- a/tests/conftest.py
+++ b/tests/conftest.py
@@ -1,8 +1,9 @@
 from functools import wraps, partial
-from http.server import SimpleHTTPRequestHandler, HTTPServer
+from http.server import SimpleHTTPRequestHandler, ThreadingHTTPServer
 
 import sys
 import pytest
+import threading
 import torch.multiprocessing as mp
 
 
@@ -21,9 +22,10 @@ def pytest_pyfunc_call(pyfuncitem):
         return True
 
 
-def run_file_server(root_dir):
+@pytest.fixture
+def tmpdir_server(tmpdir):
     if sys.version_info >= (3, 7):
-        Handler = partial(SimpleHTTPRequestHandler, directory=root_dir)
+        Handler = partial(SimpleHTTPRequestHandler, directory=str(tmpdir))
     else:
         # unfortunately SimpleHTTPRequestHandler doesn't accept the directory arg in python3.6
         # so we have to hack it like this
@@ -36,15 +38,12 @@ def translate_path(self, path):
                 # get the relative path
                 relpath = os.path.relpath(path, os.getcwd())
                 # return the full path from root_dir
-                return os.path.join(root_dir, relpath)
-
-    with HTTPServer(('', 8000), Handler) as httpd:
-        httpd.serve_forever()
-
-
-@pytest.fixture
-def tmpdir_server(tmpdir):
-    p = mp.Process(target=run_file_server, args=(str(tmpdir),))
-    p.start()
-    yield
-    p.terminate()
+                return os.path.join(str(tmpdir), relpath)
+
+    with ThreadingHTTPServer(('', 0), Handler) as server:
+        server_thread = threading.Thread(target=server.serve_forever)
+        # Exit the server thread when the main thread terminates
+        server_thread.daemon = True
+        server_thread.start()
+        yield server.server_address
+        server.shutdown()

From d88340124a22870eaf3529fc8d968fcf072d300b Mon Sep 17 00:00:00 2001
From: Peter Yu <2057325+yukw777@users.noreply.github.com>
Date: Sun, 31 May 2020 13:16:16 -0400
Subject: [PATCH 11/18] test fixes

---
 tests/trainer/test_trainer.py | 13 ++++++++-----
 1 file changed, 8 insertions(+), 5 deletions(-)

diff --git a/tests/trainer/test_trainer.py b/tests/trainer/test_trainer.py
index 78b6a543779b2..d376823484f76 100644
--- a/tests/trainer/test_trainer.py
+++ b/tests/trainer/test_trainer.py
@@ -60,7 +60,7 @@ def test_no_val_module(monkeypatch, tmpdir, tmpdir_server):
 
     # load new model from url
     model_3 = EvalModelTemplate.load_from_checkpoint(
-        checkpoint_path='http://localhost:8000/save_test.ckpt',
+        checkpoint_path=f'http://{tmpdir_server[0]}:{tmpdir_server[1]}/save_test.ckpt',
         hparams_file=hparams_path
     )
     model_3.eval()
@@ -102,7 +102,7 @@ def test_no_val_end_module(monkeypatch, tmpdir, tmpdir_server):
 
     # load new model from url
     model_3 = EvalModelTemplate.load_from_checkpoint(
-        checkpoint_path='http://localhost:8000/save_test.ckpt',
+        checkpoint_path=f'http://{tmpdir_server[0]}:{tmpdir_server[1]}/save_test.ckpt',
         hparams_file=hparams_path
     )
     model_3.eval()
@@ -339,7 +339,8 @@ def test_model_freeze_unfreeze():
     model.unfreeze()
 
 
-def test_resume_from_checkpoint_epoch_restored(monkeypatch, tmpdir, tmpdir_server):
+@pytest.mark.parametrize('url_ckpt', [True, False])
+def test_resume_from_checkpoint_epoch_restored(monkeypatch, tmpdir, tmpdir_server, url_ckpt):
     """Verify resuming from checkpoint runs the right number of epochs"""
     # set $TORCH_HOME, which determines torch hub's cache path, to tmpdir
     monkeypatch.setenv('TORCH_HOME', tmpdir)
@@ -394,8 +395,10 @@ def increment_on_load_checkpoint(self, _):
 
     # Other checkpoints can be uncommented if/when resuming mid-epoch is supported
     checkpoints = sorted(glob.glob(os.path.join(trainer.checkpoint_callback.dirpath, '*.ckpt')))
-    # add some url checkpoints
-    checkpoints += ['http://localhost:8000/' + os.path.basename(check) for check in checkpoints]
+    if url_ckpt:
+        # transform local paths into url checkpoints
+        checkpoints = [f'http://{tmpdir_server[0]}:{tmpdir_server[1]}/' +
+                       os.path.basename(check) for check in checkpoints]
 
     for check in checkpoints:
         next_model = _new_model()

From 18d7825cf2f99eec599ed7a5d2ac7fa36dbc3d06 Mon Sep 17 00:00:00 2001
From: Peter Yu <2057325+yukw777@users.noreply.github.com>
Date: Sun, 31 May 2020 13:20:09 -0400
Subject: [PATCH 12/18] pep8 fix

---
 tests/trainer/test_trainer.py | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/tests/trainer/test_trainer.py b/tests/trainer/test_trainer.py
index d376823484f76..934eb5f8c59cf 100644
--- a/tests/trainer/test_trainer.py
+++ b/tests/trainer/test_trainer.py
@@ -397,8 +397,9 @@ def increment_on_load_checkpoint(self, _):
     checkpoints = sorted(glob.glob(os.path.join(trainer.checkpoint_callback.dirpath, '*.ckpt')))
     if url_ckpt:
         # transform local paths into url checkpoints
-        checkpoints = [f'http://{tmpdir_server[0]}:{tmpdir_server[1]}/' +
-                       os.path.basename(check) for check in checkpoints]
+        checkpoints = [
+            f'http://{tmpdir_server[0]}:{tmpdir_server[1]}/' + os.path.basename(check) for check in checkpoints
+        ]
 
     for check in checkpoints:
         next_model = _new_model()

From b71f69abd52b0f10fd204330f2174b18abd91cee Mon Sep 17 00:00:00 2001
From: Peter Yu <2057325+yukw777@users.noreply.github.com>
Date: Sun, 31 May 2020 13:26:01 -0400
Subject: [PATCH 13/18] ThreadingHTTPServer support in 3.6

---
 tests/conftest.py | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/tests/conftest.py b/tests/conftest.py
index 627a7837e376e..216bbe171d018 100644
--- a/tests/conftest.py
+++ b/tests/conftest.py
@@ -1,5 +1,5 @@
 from functools import wraps, partial
-from http.server import SimpleHTTPRequestHandler, ThreadingHTTPServer
+from http.server import SimpleHTTPRequestHandler
 
 import sys
 import pytest
@@ -26,6 +26,7 @@ def pytest_pyfunc_call(pyfuncitem):
 def tmpdir_server(tmpdir):
     if sys.version_info >= (3, 7):
         Handler = partial(SimpleHTTPRequestHandler, directory=str(tmpdir))
+        from http.server import ThreadingHTTPServer
     else:
         # unfortunately SimpleHTTPRequestHandler doesn't accept the directory arg in python3.6
         # so we have to hack it like this
@@ -40,6 +41,13 @@ def translate_path(self, path):
                 # return the full path from root_dir
                 return os.path.join(str(tmpdir), relpath)
 
+        # ThreadingHTTPServer was added in 3.7, so we need to define it ourselves
+        from socketserver import ThreadingMixIn
+        from http.server import HTTPServer
+
+        class ThreadingHTTPServer(ThreadingMixIn, HTTPServer):
+            daemon_threads = True
+
     with ThreadingHTTPServer(('', 0), Handler) as server:
         server_thread = threading.Thread(target=server.serve_forever)
         # Exit the server thread when the main thread terminates

From 3e4b99d900855cbd9e7f8795026fded3fd93e56d Mon Sep 17 00:00:00 2001
From: Peter Yu <2057325+yukw777@users.noreply.github.com>
Date: Sun, 31 May 2020 13:26:51 -0400
Subject: [PATCH 14/18] pep8 fix

---
 tests/trainer/test_trainer.py | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/tests/trainer/test_trainer.py b/tests/trainer/test_trainer.py
index 934eb5f8c59cf..000679f0b4420 100644
--- a/tests/trainer/test_trainer.py
+++ b/tests/trainer/test_trainer.py
@@ -397,8 +397,9 @@ def increment_on_load_checkpoint(self, _):
     checkpoints = sorted(glob.glob(os.path.join(trainer.checkpoint_callback.dirpath, '*.ckpt')))
     if url_ckpt:
         # transform local paths into url checkpoints
+        ip, port = tmpdir_server
         checkpoints = [
-            f'http://{tmpdir_server[0]}:{tmpdir_server[1]}/' + os.path.basename(check) for check in checkpoints
+            f'http://{ip}:{port}/' + os.path.basename(check) for check in checkpoints
         ]
 
     for check in checkpoints:

From ddce3bb1315b1b0c13bd06ebe89737cdc355ed1e Mon Sep 17 00:00:00 2001
From: Peter Yu <2057325+yukw777@users.noreply.github.com>
Date: Mon, 8 Jun 2020 10:05:01 -0400
Subject: [PATCH 15/18] fix changelog

---
 CHANGELOG.md | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 2f8eb14a83f10..b0b00fda7ff46 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -33,8 +33,7 @@ The format is based on [Keep a Changelog](http://keepachangelog.com/en/1.0.0/).
 - Added a model hook `transfer_batch_to_device` that enables moving custom data structures to the target device ([1756](https://github.com/PyTorchLightning/pytorch-lightning/pull/1756))
 - Added [black](https://black.readthedocs.io/en/stable/) formatter for the code with code-checker on pull ([1610](https://github.com/PyTorchLightning/pytorch-lightning/pull/1610))
 - Added back the slow spawn ddp implementation as `ddp_spawn` ([#2115](https://github.com/PyTorchLightning/pytorch-lightning/pull/2115))
-
-- Added loading checkpoings from URLs ([#1532](https://github.com/PyTorchLightning/pytorch-lightning/issues/1532))
+- Added loading checkpoings from URLs ([#1667](https://github.com/PyTorchLightning/pytorch-lightning/issues/1667))
 
 ### Changed
 

From f25ccdd0a562d343dea695584add01aca0d2a7cf Mon Sep 17 00:00:00 2001
From: Peter Yu <2057325+yukw777@users.noreply.github.com>
Date: Mon, 8 Jun 2020 10:13:07 -0400
Subject: [PATCH 16/18] separate tests for urls

---
 tests/trainer/test_trainer.py | 26 ++++++++------------------
 1 file changed, 8 insertions(+), 18 deletions(-)

diff --git a/tests/trainer/test_trainer.py b/tests/trainer/test_trainer.py
index 000679f0b4420..c84d2de237a72 100644
--- a/tests/trainer/test_trainer.py
+++ b/tests/trainer/test_trainer.py
@@ -21,7 +21,8 @@
 from tests.base import EvalModelTemplate
 
 
-def test_no_val_module(monkeypatch, tmpdir, tmpdir_server):
+@pytest.mark.parametrize('url_ckpt', [True, False])
+def test_no_val_module(monkeypatch, tmpdir, tmpdir_server, url_ckpt):
     """Tests use case where trainer saves the model, and user loads it from tags independently."""
     # set $TORCH_HOME, which determines torch hub's cache path, to tmpdir
     monkeypatch.setenv('TORCH_HOME', tmpdir)
@@ -52,21 +53,16 @@ def test_no_val_module(monkeypatch, tmpdir, tmpdir_server):
     # load new model
     hparams_path = tutils.get_data_path(logger, path_dir=tmpdir)
     hparams_path = os.path.join(hparams_path, 'hparams.yaml')
+    ckpt_path = f'http://{tmpdir_server[0]}:{tmpdir_server[1]}/{os.path.basename(new_weights_path)}' if url_ckpt else new_weights_path
     model_2 = EvalModelTemplate.load_from_checkpoint(
-        checkpoint_path=new_weights_path,
+        checkpoint_path=ckpt_path,
         hparams_file=hparams_path
     )
     model_2.eval()
 
-    # load new model from url
-    model_3 = EvalModelTemplate.load_from_checkpoint(
-        checkpoint_path=f'http://{tmpdir_server[0]}:{tmpdir_server[1]}/save_test.ckpt',
-        hparams_file=hparams_path
-    )
-    model_3.eval()
-
 
-def test_no_val_end_module(monkeypatch, tmpdir, tmpdir_server):
+@pytest.mark.parametrize('url_ckpt', [True, False])
+def test_no_val_end_module(monkeypatch, tmpdir, tmpdir_server, url_ckpt):
     """Tests use case where trainer saves the model, and user loads it from tags independently."""
     # set $TORCH_HOME, which determines torch hub's cache path, to tmpdir
     monkeypatch.setenv('TORCH_HOME', tmpdir)
@@ -94,19 +90,13 @@ def test_no_val_end_module(monkeypatch, tmpdir, tmpdir_server):
     # load new model
     hparams_path = tutils.get_data_path(logger, path_dir=tmpdir)
     hparams_path = os.path.join(hparams_path, 'hparams.yaml')
+    ckpt_path = f'http://{tmpdir_server[0]}:{tmpdir_server[1]}/{os.path.basename(new_weights_path)}' if url_ckpt else new_weights_path
     model_2 = EvalModelTemplate.load_from_checkpoint(
-        checkpoint_path=new_weights_path,
+        checkpoint_path=ckpt_path,
         hparams_file=hparams_path
     )
     model_2.eval()
 
-    # load new model from url
-    model_3 = EvalModelTemplate.load_from_checkpoint(
-        checkpoint_path=f'http://{tmpdir_server[0]}:{tmpdir_server[1]}/save_test.ckpt',
-        hparams_file=hparams_path
-    )
-    model_3.eval()
-
 
 def test_gradient_accumulation_scheduling(tmpdir):
     """

From bdd627eba2cf6387507837ba041fd10d2f1a52ba Mon Sep 17 00:00:00 2001
From: Jirka Borovec <Borda@users.noreply.github.com>
Date: Wed, 10 Jun 2020 00:52:39 +0200
Subject: [PATCH 17/18] typo

Co-authored-by: Peter Yu <2057325+yukw777@users.noreply.github.com>
---
 CHANGELOG.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index b0b00fda7ff46..801ebd6af74b4 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -33,7 +33,7 @@ The format is based on [Keep a Changelog](http://keepachangelog.com/en/1.0.0/).
 - Added a model hook `transfer_batch_to_device` that enables moving custom data structures to the target device ([1756](https://github.com/PyTorchLightning/pytorch-lightning/pull/1756))
 - Added [black](https://black.readthedocs.io/en/stable/) formatter for the code with code-checker on pull ([1610](https://github.com/PyTorchLightning/pytorch-lightning/pull/1610))
 - Added back the slow spawn ddp implementation as `ddp_spawn` ([#2115](https://github.com/PyTorchLightning/pytorch-lightning/pull/2115))
-- Added loading checkpoings from URLs ([#1667](https://github.com/PyTorchLightning/pytorch-lightning/issues/1667))
+- Added loading checkpoints from URLs ([#1667](https://github.com/PyTorchLightning/pytorch-lightning/issues/1667))
 
 ### Changed
 

From ae76d52741dd0546ef010eea02e6018002b7a3c1 Mon Sep 17 00:00:00 2001
From: Jirka Borovec <Borda@users.noreply.github.com>
Date: Thu, 11 Jun 2020 21:52:23 +0200
Subject: [PATCH 18/18] Apply suggestions from code review

---
 pytorch_lightning/core/saving.py | 2 +-
 tests/trainer/test_trainer.py    | 4 +---
 2 files changed, 2 insertions(+), 4 deletions(-)

diff --git a/pytorch_lightning/core/saving.py b/pytorch_lightning/core/saving.py
index 092424f870d90..ed299bb8a816e 100644
--- a/pytorch_lightning/core/saving.py
+++ b/pytorch_lightning/core/saving.py
@@ -53,7 +53,7 @@ def load_from_checkpoint(
         Primary way of loading a model from a checkpoint. When Lightning saves a checkpoint
         it stores the arguments passed to `__init__`  in the checkpoint under `module_arguments`
 
-        Any arguments specified through \*args and \*\*kwargs will override args stored in `module_arguments`.
+        Any arguments specified through \*args and \*\*kwargs will override args stored in `hparams`.
 
         Args:
             checkpoint_path: Path to checkpoint. This can also be a URL.
diff --git a/tests/trainer/test_trainer.py b/tests/trainer/test_trainer.py
index c84d2de237a72..caf1632ec3474 100644
--- a/tests/trainer/test_trainer.py
+++ b/tests/trainer/test_trainer.py
@@ -388,9 +388,7 @@ def increment_on_load_checkpoint(self, _):
     if url_ckpt:
         # transform local paths into url checkpoints
         ip, port = tmpdir_server
-        checkpoints = [
-            f'http://{ip}:{port}/' + os.path.basename(check) for check in checkpoints
-        ]
+        checkpoints = [f'http://{ip}:{port}/' + os.path.basename(check) for check in checkpoints]
 
     for check in checkpoints:
         next_model = _new_model()