Hi all, my current work involves interacting with MS Project files. The binary file format is pretty tedious to interact with. The best third party library I have found for reading the files is written in Java. I have written a small test Java project that I have interoperating with a test Elixir p…

[image] mindok: The only problem is that the java program doesn’t die when the owning BEAM process dies or BEAM is terminated. This is discussed here: [erlang-questions] How do you kill an OS process that was opened with open_port on a brutal_kill? , and it sounds like it all relies on the progra…

Besides of the already mentioned erlport there are a couple of other projects available, like porcelain which relies on a wrapper written in Golang, which has to be installed seperately, or rambo which explicitely not only manages the lifecycle of the program, but also is able to wrap those programs…

Thanks - I’m watching for EOF in my code and that doesn’t appear to be triggering. I’ll double-check and go to ErlPort if I can’t get it working.

Thanks @NobbZ - I have no problem receiving the inputs from the external process, it’s just shutting it down cleanly afterwards that’s the problem. I’ll double-check receives of EOF first, then I’ll try on Linux to see if there is some weird Windows effect, then I’ll see if ErlPorts does a more agg…

OK, problem exists between chair & keyboard. My main loop was badly behaved. I stripped it back to the most basic stdin read loop and it terminates ok. Time to start building it up again and see where it fails. For reference, here’s a minimal Java program that works nicely over ports, terminating w…

Creator of Rambo here. Don’t use libraries if you’re writing your own port. Libraries are for working around external programs that cannot be changed. Your minimal program is a good start, just need to read (block on) standard input on another thread so your MS Project job can run. If you don’t ca…

[image] NobbZ: as far as I remember you need to have rust installed to compile the library. Thanks for the mention. To clarify, Rambo only requires the Rust compiler if you are not using Linux, macOS or Windows. Bundled binaries should cover most users.

Thanks @jayjun - yes, the java process will be long lived. I’ve worked up a more extended example that uses Erlang ETF to transmit the payload back and forth. The Ericsson JInterface library has all the parsing and packaging routines. There are a couple of gotchas that I’ll write up (eg the OtpOutpu…

[image] mindok: The Java side can respond synchronously to each call in my case which simplifies things on that side. Cool, just be careful of the classic pipe buffer deadlock if you’re not continuously reading while writing. And you cannot terminate early if the port is closed or if the Erla…

Thanks @jayjun - that sounds like some hard-won experience right there!

[image] mindok: I’ve worked up a more extended example that uses Erlang ETF to transmit the payload back and forth. The Ericsson JInterface library has all the parsing and packaging routines. There are a couple of gotchas that I’ll write up (eg the OtpOutputStream doesn’t write the first byte - …

Killing java processes started from Port.open

Questions & Help Questions

mindok April 6, 2021, 8:28am 14

Hi @why,

You can take a look here for some sample code: