gristlabs_grist-core/sandbox/grist/sandbox.py
Alex Hall 84ddbc448b (core) Add test_replay for easily replaying data sent to the sandbox purely within python
Summary:
Run JS with a value for SANDBOX_BUFFERS_DIR, then run test_replay in python with the same value to replay just the python code.

See test_replay.py for more info.

Test Plan:
Record some data, e.g. `SANDBOX_BUFFERS_DIR=manual npm start` or `SANDBOX_BUFFERS_DIR=server ./test/testrun.sh server`.

Then run `SANDBOX_BUFFERS_DIR=server python -m unittest test_replay` from within `core/sandbox/grist` to replay the input from the JS.

Sample of the output will look like this:

```
Checking /tmp/sandbox_buffers/server/2021-06-16T15:13:59.958Z
True
Checking /tmp/sandbox_buffers/server/2021-06-16T15:16:37.170Z
True
Checking /tmp/sandbox_buffers/server/2021-06-16T15:14:22.378Z
True
```

Reviewers: paulfitz, dsagal

Reviewed By: dsagal

Differential Revision: https://phab.getgrist.com/D2866
2021-06-30 16:56:09 +02:00

111 lines
3.5 KiB
Python

"""
Implements the python side of the data engine sandbox, which allows us to register functions on
the python side and call them from Node.js.
Usage:
import sandbox
sandbox.register(func_name, func)
sandbox.call_external("hello", 1, 2, 3)
sandbox.run()
"""
import os
import marshal
import sys
import traceback
def log(msg):
sys.stderr.write(str(msg) + "\n")
sys.stderr.flush()
class Sandbox(object):
"""
This class works in conjunction with Sandbox.js to allow function calls
between the Node process and this sandbox.
The sandbox provides two pipes (on fds 3 and 4) to send data to and from the sandboxed
process. Data on these is serialized using `marshal` module. All messages are comprised of a
msgCode followed immediatedly by msgBody, with the following msgCodes:
CALL = call to the other side. The data must be an array of [func_name, arguments...]
DATA = data must be a value to return to a call from the other side
EXC = data must be an exception to return to a call from the other side
"""
CALL = None
DATA = True
EXC = False
def __init__(self, external_input, external_output):
self._functions = {}
self._external_input = external_input
self._external_output = external_output
@classmethod
def connected_to_js_pipes(cls):
external_input = os.fdopen(3, "rb", 64 * 1024)
external_output = os.fdopen(4, "wb", 64 * 1024)
return cls(external_input, external_output)
def _send_to_js(self, msgCode, msgBody):
# (Note that marshal version 2 is the default; we specify it explicitly for clarity. The
# difference with version 0 is that version 2 uses a faster binary format for floats.)
# For large data, JS's Unmarshaller is very inefficient parsing it if it gets it piecewise.
# It's much better to ensure the whole blob is sent as one write. We marshal the resulting
# buffer again so that the reader can quickly tell how many bytes to expect.
buf = marshal.dumps((msgCode, msgBody), 2)
marshal.dump(buf, self._external_output, 2)
self._external_output.flush()
def call_external(self, name, *args):
self._send_to_js(Sandbox.CALL, (name,) + args)
(msgCode, data) = self.run(break_on_response=True)
if msgCode == Sandbox.EXC:
raise Exception(data)
return data
def register(self, func_name, func):
self._functions[func_name] = func
def run(self, break_on_response=False):
while True:
try:
msgCode = marshal.load(self._external_input)
data = marshal.load(self._external_input)
except EOFError:
break
if msgCode != Sandbox.CALL:
if break_on_response:
return (msgCode, data)
continue
if not isinstance(data, list) or len(data) < 1:
raise ValueError("Bad call " + data)
try:
fname = data[0]
args = data[1:]
ret = self._functions[fname](*args)
self._send_to_js(Sandbox.DATA, ret)
except Exception as e:
traceback.print_exc()
self._send_to_js(Sandbox.EXC, "%s %s" % (type(e).__name__, e))
if break_on_response:
raise Exception("Sandbox disconnected unexpectedly")
default_sandbox = None
def get_default_sandbox():
global default_sandbox
if default_sandbox is None:
default_sandbox = Sandbox.connected_to_js_pipes()
return default_sandbox
def call_external(name, *args):
return get_default_sandbox().call_external(name, *args)
def register(func_name, func):
get_default_sandbox().register(func_name, func)
def run():
get_default_sandbox().run()