fastly-exporter-2.1.0-linux-amd64 doesn't work in alpine

[ljagiello]

fastly-exporter-2.1.0-linux-amd64 doesn't work in alpine container.

fastly-exporter-2.0.0-linux-amd64:

➜  fastly-exporter cat Dockerfile-2.0.0
FROM alpine:3.8

RUN apk add --no-cache ca-certificates

RUN wget https://github.com/peterbourgon/fastly-exporter/releases/download/v2.0.0/fastly-exporter-2.0.0-linux-amd64 -O /fastly-exporter && chmod a+x fastly-exporter

ENTRYPOINT ["/fastly-exporter", "-endpoint", "http://0.0.0.0:8080/metrics"]
➜  fastly-exporter docker build --pull -t fastly-exporter-2.0.0 -f Dockerfile-2.0.0 .
[…]
➜  fastly-exporter docker run --rm fastly-exporter-2.0.0:latest
level=error err="-token is required"

fastly-exporter-2.1.0-linux-amd64:

➜  fastly-exporter cat Dockerfile-2.1.0
FROM alpine:3.8

RUN apk add --no-cache ca-certificates

RUN wget https://github.com/peterbourgon/fastly-exporter/releases/download/v2.1.0/fastly-exporter-2.1.0-linux-amd64 -O /fastly-exporter && chmod a+x fastly-exporter

ENTRYPOINT ["/fastly-exporter", "-endpoint", "http://0.0.0.0:8080/metrics"]
➜  fastly-exporter docker build --pull -t fastly-exporter-2.1.0 -f Dockerfile-2.1.0 .
[…]
➜  fastly-exporter docker run --rm fastly-exporter-2.1.0:latest
standard_init_linux.go:190: exec user process caused "no such file or directory"

It looks like 2.1.0 binary is not linked statically.

/ # ldd fastly-exporter-2.1.0-linux-amd64
	/lib64/ld-linux-x86-64.so.2 (0x7fa4e59f2000)
	libpthread.so.0 => /lib64/ld-linux-x86-64.so.2 (0x7fa4e59f2000)
	libc.so.6 => /lib64/ld-linux-x86-64.so.2 (0x7fa4e59f2000)
/ # ldd fastly-exporter-2.0.0-linux-amd64
ldd: fastly-exporter-2.0.0-linux-amd64: Not a valid dynamic program

[mrnetops]

Huh. I used @peterbourgon s release.fish script for the binaries.

Looking closer, it doesn't look like the release.fish produced binaries are intended to be statically linked as there is not a reference to CGO_ENABLED=0 in the build command.

I would suggest not relying on the release binaries to be statically linked. @peterbourgon thoughts?

With regards to your Dockerfile construction, I would suggest using mrnetops/fastly-exporter from docker hub or the repository Dockerfile, which explicitly build a statically linked version for the container.

Otherwise, you are attempting to rely on release build side effects.

those images are also smaller as well ;)

docker images
REPOSITORY                  TAG                 IMAGE ID            CREATED             SIZE
ljagiello/fastly-exporter   latest              96839a74ade7        17 seconds ago      16MB
mrnetops/fastly-exporter    latest              41a65eb58cdf        2 hours ago         11.3MB
alpine                      3.8                 196d12cf6ab1        2 months ago        4.41MB

Please let me know if I'm missing a nuance of your usecase / docker build.

[ljagiello]

Oh sure I can hack that around, it's just a different behavior between versions.

[ljagiello]

PR: #23

[mrnetops]

Release updated with new release.fish binaries.

I will however still suggest you not rely on wget of release binaries to do the right thing for your containers.