Wandering Thoughts archives

2023-04-07

Go 1.21 will (likely) have a static toolchain on Linux

A while back, I lamented on the Fediverse:

Current status: yak shaving a Go 1.17 built on Ubuntu 20.04 so I can build Go 1.20 on 20.04 so I can build a binary with Go 1.20 that will run on 20.04 for reasons.

The easy way to solve this problem would have been to download an official binary release tarball, because these are built so that they'll run on pretty much any Linux (presumably on a system with a very old glibc, since they're actually dynamically linked, with glibc symbol versioning only requiring 2.3.2 or later). Because I already had a whole set of Go source trees, I picked the hard way.

At this point you might wonder why the Go toolchain is dynamically linked against the system glibc. Although I haven't tried to analyze symbol usage, the obvious assumption is that it's dynamically linked because various Go tools want to download packages over the network, which requires looking up DNS names, which is a very common cause of dynamically linking to glibc.

The good news, as pointed out to me by @magical, is that in Go 1.21 and later the plan is for the compiler to be built using the pure Go resolver only and to be a static executable. Relevant reading here is apparently issue #53862 and issue #57007 (via). As far as I know, the elements of this plan have already landed in the Go development version; my current development Go binaries are static binaries.

; ./go version
go version devel go1.21-66cac9e1e4 Fri Apr 7 23:34:21 2023 +0000 linux/amd64
; ldd ./go
        not a dynamic executable

Unless the Go developers revert this for some reason, Go 1.21 and later will be static executables on Linux.

(Doing this before Go 1.21 is tricky for reasons beyond the scope of this entry.)

This is a nice little quality of life improvement for people (like me) mostly working on recent Linuxes but who periodically have to deal with older ones. It won't automatically make your own programs version-independent, but for them you can use '-tags osusergo,netgo' when you build or install Go programs.

(You might wonder why I didn't just build the Go program I needed to run on Ubuntu 20.04 with those flags in the first place. The answer is that I was distracted by the flow of circumstances. First I tried to run the program on a 20.04 machine in addition to some 22.04 ones, and got glibc version errors, so I tried to rebuild it on 20.04 to be more universal, then I had the 'go' compiler toolchain not work with the same problem, and by that point my mental focus was on 'make the compiler toolchain work'.)

programming/Go121LinuxStaticToolchain written at 23:20:23; Add Comment


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