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NGINX Unit - universal web app server - a lightweight and versatile open source server that simplifies the application stack by natively executing application code across eight different programming language runtimes.
https://unit.nginx.org
Apache License 2.0
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questions around embedding `libunit` in Julia #1038

Closed pankgeorg closed 2 months ago

pankgeorg commented 6 months ago

Hello! I'm playing around with unit, trying to hook it up to julia. Julia has a quite neat c interface which can load .so files and call into them. I'm planning to wrap the libunit in a Julia jll package and then make a wrapper that will control unit internally (please excuse my juniority 🤗)

build/lib/libunit.so: $(NXT_LIB_UNIT_OBJS) \
        build/share/pkgconfig/unit.pc \
        build/share/pkgconfig/unit-uninstalled.pc
    $(CC) -shared -o $@ $(NXT_LIB_UNIT_OBJS)

can this be streamlined somehow? Why is only a static library (.a) created as of now? Am I missing something? Is this "completely" standalone, or does it need additional files? Can this (.so) file be included in upcoming binary distributions?

ac000 commented 6 months ago

Hi @pankgeorg

Hello! I'm playing around with unit, trying to hook it up to julia. Julia has a quite neat c interface which can load .so files and call into them. I'm planning to wrap the libunit in a Julia jll package and then make a wrapper that will control unit internally (please excuse my juniority 🤗)

Sounds interesting...

* [ ]  documentation around the thread model of unit

  * How many threads does unit use?

The router process seems to start up three threads.

Some of the application processes can be threaded if you specify the 'threads' setting.

  * Are the C library calls thread safe (can I call them from many different julia threads simultaneously, or do I need to do locking julia side)?

I'm going to they are generally thread safe, as they use thread local storage, but the best way to find out is to just try it!

* [ ]  `libunit.so`: I'm making this with this rule, but I'm not sure if I'm missing anything
build/lib/libunit.so: $(NXT_LIB_UNIT_OBJS) \
      build/share/pkgconfig/unit.pc \
      build/share/pkgconfig/unit-uninstalled.pc
  $(CC) -shared -o $@ $(NXT_LIB_UNIT_OBJS)

can this be streamlined somehow? Why is only a static library (.a) created as of now? Am I missing something? Is this "completely" standalone, or does it need additional files? Can this (.so) file be included in upcoming binary distributions?

From what I can gather it's basically down to libunit not being a stable a API. It may change and if we install a changed libunit.so it may randomly break peoples stuff.

pankgeorg commented 6 months ago

From what I can gather it's basically down to libunit not being a stable a API. It may change and if we install a changed libunit.so it may randomly break peoples stuff.

I can tolerate some ABI instability, especially if the semantic versioning is respected. We won't be installing anything system wide- we would rather be loading the .so from the Julia depot (where Julia stores local code and dependencies)

lcrilly commented 2 months ago

@ac000 is this ready to be closed or moved to a discussion?

ac000 commented 2 months ago

I think the answer for now is to use the static library (although not ideal).

@pankgeorg

I'll close this for now, feel free to re-open if you have any other issues/queries...

pankgeorg commented 2 months ago

I can't load a static library from Julia, unfortunately. But no worries, I am not blocked by this in particular.