Add SHM size to the container request

[EndPositive]

The code-way of specifying --shm-size on the Docker command-line.

E.g.

var shmsize = 1073741824 // = 1GB

I've been using this to start Selenium nodes, for example.

[codecov]

Codecov Report

Merging #461 (4f15dd0) into main (d01c78a) will increase coverage by 0.19%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##             main     #461      +/-   ##
==========================================
+ Coverage   65.91%   66.11%   +0.19%     
==========================================
  Files          19       19              
  Lines        1200     1201       +1     
==========================================
+ Hits          791      794       +3     
+ Misses        303      302       -1     
+ Partials      106      105       -1     

Impacted Files	Coverage Δ
container.go	87.23% <ø> (ø)
docker.go	66.90% <100.00%> (+0.42%)	⬆️

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[mdelapenya]

Thanks for taking the time to work on this contribution, it's much than appreciated!

My comments: although the documentation for shm uses this format:

Size of /dev/shm. The format is . number must be greater than 0. Unit is optional and can be b (bytes), k (kilobytes), m (megabytes), or g (gigabytes). If you omit the unit, the system uses bytes. If you omit the size entirely, the system uses 64m.

which could advocate for a more elaborated format, I think using a format with just the bytes is great for simplicity.

What I'd take a look is at the consistency with both Docker client and the Java project, which uses bytes as default unit.

• Docker client: https:/moby/moby/blob/1a0587bd766e3ab1f6dbe808a94a41a2f54d9126/docs/api/v1.41.yaml#L1111
• TC-java: https:/testcontainers/testcontainers-java/blob/de1324ed2800eff4da326d0c23d281399d006bc0/core/src/main/java/org/testcontainers/containers/GenericContainer.java#L180

Once updated to use bytes, I think this PR is perfect!

[EndPositive]

Hey 👋, thanks for the detailed comment!

I agree to keep it simple and not bother with parsing of the different units.

Good point about the default unit though. It looks like I made a mistake writing that docstring. By default, Golang's HostConfig is in Bytes, and since I directly pass our container request to that hostconfig, it should have also been in bytes.

I've updated the docstring ^^