Use GCSClient instead of PythonGCSClient

[glennmoy]

Break off of https://github.com/beacon-biosignals/Ray.jl/pull/202

Closes #76

Two things worth calling out:

• Unlike the PythonGcsClient the GcsClient has no direct interface for specifying a timeout. This is instead set through RayConfig parameters which can be overriden via environment variables.
• Attempting to Connect to unintiated GCS Servers issues a warning message before killing the driver process after a 1-min timeout.

[codecov[bot]]

Codecov Report

Merging #211 (9bb6921) into main (caddc0e) will increase coverage by 0.46%. The diff coverage is 100.00%.

@@            Coverage Diff             @@
##             main     #211      +/-   ##
==========================================
+ Coverage   97.65%   98.12%   +0.46%     
==========================================
  Files          12       12              
  Lines         640      639       -1     
==========================================
+ Hits          625      627       +2     
+ Misses         15       12       -3     

Flag	Coverage Δ
Ray.jl	98.12% <100.00%> (+0.46%)	:arrow_up:

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Files	Coverage Δ
src/function_manager.jl	97.77% <100.00%> (+5.47%)	:arrow_up:
src/ray_julia_jll/common.jl	95.30% <100.00%> (+0.19%)	:arrow_up:

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[omus]

Failures definitely look related:

 [ Info: Connecting function manager to GCS at 10.0.0.105:6379...
terminate called after throwing an instance of 'std::runtime_error'
  what():  NotFound: Failed to find the key

signal (6): Aborted
in expression starting at /home/runner/work/Ray.jl/Ray.jl/test/ray_serializer.jl:1
pthread_kill at /lib/x86_64-linux-gnu/libc.so.6 (unknown line)
raise at /lib/x86_64-linux-gnu/libc.so.6 (unknown line)

– https://github.com/beacon-biosignals/Ray.jl/actions/runs/6645852901/job/18058052127?pr=211#step:12:215

 [ Info: Connecting function manager to GCS at 127.0.0.1:6379...
libc++abi: terminating due to uncaught exception of type std::runtime_error: NotFound: Failed to find the key

signal (6): Abort trap: 6
in expression starting at /Users/runner/work/Ray.jl/Ray.jl/test/ray_serializer.jl:81
__pthread_kill at /usr/lib/system/libsystem_kernel.dylib (unknown line)
Allocations: 44751822 (Pool: 44725417; Big: 26405); GC: 51

– https://github.com/beacon-biosignals/Ray.jl/actions/runs/6645852901/job/18058052370?pr=211#step:12:211

[omus]

I can manage to reproduce this on my local machine:

┌ Debug: Skipping registering ownership for ObjectRef("00ffffffffffffffffffffffffffffffffffffff4300000013000000") as object has known owner
└ @ Ray ~/.julia/dev/Ray/src/object_ref.jl:128
libc++abi: terminating due to uncaught exception of type std::runtime_error: NotFound: Failed to find the key

[1307] signal (6): Abort trap: 6
in expression starting at /Users/cvogt/.julia/dev/Ray/test/runtests.jl:19
__pthread_kill at /usr/lib/system/libsystem_kernel.dylib (unknown line)
Allocations: 30846806 (Pool: 30821062; Big: 25744); GC: 44
ERROR: Package Ray errored during testing (received signal: 6)

[omus]

The issue noticed above was just due to us failing to Disconnect the JuliaGcsClient used in the function_manager.jl tests. I've added a destructor to the JuliaGcsClient to automatically disconnect the client to avoid the SIGABRT failure. However, since users of JuliaGcsClient should really be handling disconnecting themselves I added in a STDERR warning from C++ indicating that a connected JuliaGcsClient failed to disconnect on their own. As Ray.jl users aren't exposed to this class mostly this is just a reminder for Ray.jl developers to be explicit about disconnecting.

[glennmoy]

The issue noticed above was just due to us failing to Disconnect the JuliaGcsClient used in the function_manager.jl tests. I've added a destructor to the JuliaGcsClient to automatically disconnect the client to avoid the SIGABRT failure. However, since users of JuliaGcsClient should really be handling disconnecting themselves I added in a STDERR warning from C++ indicating that a connected JuliaGcsClient failed to disconnect on their own. As Ray.jl users aren't exposed to this class mostly this is just a reminder for Ray.jl developers to be explicit about disconnecting.

yeah when I removed the finalizer from the inner constructor as per your suggestion above I should have done so by reverting https://github.com/beacon-biosignals/Ray.jl/pull/211/commits/6b98717caa778604f27918461dc30f6cc7b3d9bf as I missed adding back the Disconnect