instructions for how to use as backend for python fitsio

[beckermr]

@cruzzil Do you happen to have instructions for how to use this rust implementation as a backend for the Python fitsio code?

I am looking into adding support, but I am a rust n00b, and so a build example would be helpful!

[cruzzil]

How does the python version currently depend on cfitsio? Does it compile it and link the dynamic library? Or just use the system install?

[beckermr]

We can either link against the system library or we bundle the static library into the C extension.

[cruzzil]

What I did:

Clone the repo / download the source tarball, run cargo build --release and then in the target/release directory, copy the .so/.dll/.dylib to your repo's lib directly and then link against that. This is what i did when i tested your unit tests linked against rsfitsio. I did a ln -s librsfitsio.so libcfitsio.so so that I didn't have to change anything in your library.

Note that this is very much a work in progress, whilst it was a line-by-line translation for the most part, there may be some edge cases I've missed.

I haven't tested against your unit tests for about a year, but last time they were all passing. Can try again in the next couple of weeks.

[beckermr]

Got it. I think I can add support so no manual steps are required.

[beckermr]

See this PR esheldon/fitsio#523

There are a large number of test failures due to what appear to be bugs in rsfitsio. I have not dug into each one.

[beckermr]

Also the threading performance when attempting to release the GIL is a lot worse than cfitsio. Does rsfitsio have global locks in it?

[cruzzil]

Will check them out.

Hmm interesting regarding the multithreaded performance, should be similar locks to how c version is going it. Will also check it out.

[beckermr]

I think one of the main bugs is #60

[cruzzil]

Give it a go now from main branch. It seems to work for me (removing all the rsfitsio specific skips, etc in your test cases)

[beckermr]

I opened another issue on the repo related to lossy image compression.

[cruzzil]

Sorted, good spot.

[beckermr]

Closing this. Thank you!