Use default tmpdir for temporary files

[ekohl]

This replaces the (as of Go 1.17) deprecated ioutil.TempFile with os.CreateTemp. When calling os.CreateTemp with an empty dir the default directory for temporary files is used. On UNIX that's $TMPDIR if non-empty or /tmp.

[ekohl]

@adamruzicka this is my first patch in Go. I don't know what the convention is when supporting older versions. I'm guessing Go 1.15 is still needed for EL7 support.

[adamruzicka]

I don't know what the convention is when supporting older versions

I'm not really a go person, but I'm afraid there is none.

Go 1.15 is still needed for EL7 support.

Well, yes and no. As far as I know the go compiler creates static binaries so we could build on newer EL and ship the resulting artifacts on older ELs but I guess this would mean we'd have to deviate quite a bit from how we normally package things.

[ekohl]

I wonder how we're consuming golang. EPEL7 has golang 1.19.9 and EL8 has golang 1.20.4 so do we really need to support older versions? Or is it for downstream?

[adamruzicka]

As far as I know in upstream we take it from epel, which back then only had 1.15. In downstream go seems to be added to the buildroot, in july last year it had 1.16. It sounds like it should be safe to drop 1.15.

[adamruzicka]

Now that I'm thinking about it, I'm not sure if this would actually help. The worker is spawned by yggdrasil and yggdrasil trims down the environment substantially before starting the worker. I'm not sure if TEMPDIR survives this purge.

[ekohl]

That's a fair point, but it still would be better to avoid hardcoding a path. For now to see if it builds I added a commit that updates the matrix.

[ekohl]

That looks green so I opened #14.

[ekohl]

Rebased

[ekohl]

@adamruzicka any progress on this?

[adamruzicka]

Included in #16 at 1bc71c7, thank you @ekohl !