Zstd: Docker image for zstd

[vaibhavsood]

Hi,

Want to check if there is a docker image/Dockerfile for zstd which is officially supported? I could not find one under dockerhub official images https://hub.docker.com/explore/

If not, want to check if there is any plan to add an official zstd image to dockerhub? https://docs.docker.com/docker-hub/official_repos/#how-do-i-create-a-new-official-repository

[Cyan4973]

We haven't planned any docker image.
It seems like a reasonable idea, though the support of someone experienced in this process would be gladly welcomed.

[gyscos]

To be clear, you're looking for a docker image that contains a pre-built zstd binary?
If so, here is a dockerfile that generates such an image (note: it uses a multi-stage build, and requires docker >= 17.05 to build the image):

# Dockerfile

# First image to build the binary
FROM alpine as builder

RUN apk --no-cache add make gcc libc-dev
COPY . /src
RUN mkdir /pkg && cd /src && make && make DESTDIR=/pkg install

# Second minimal image to only keep the built binary
FROM alpine

# Copy the built files
COPY --from=builder /pkg /

# Copy the license as well
RUN mkdir -p /usr/local/share/licenses/zstd
COPY --from=builder /src/LICENSE /usr/local/share/licences/zstd/

# Just run `zstd` if no other command is given
CMD ["/usr/local/bin/zstd"]

Then in the zstd directory:

$ docker build -t zstd .
$ echo foo | docker run -i --rm zstd | docker run -i --rm zstd zstdcat
foo

This results in a 6.42MB image.

[Cyan4973]

Would it be useful to host such a script is /contrib/docker ?

[gyscos]

I suppose. I think the main idea is to use this script to build an image, and then push this image to the official docker hub - ideally people would use this official image rather than create one themselves.
So it's more of an internal-use script, but it may still be a good idea to keep it in this repository, and contrib/docker sounds like a good place for that.

[gyscos]

There may be some more bikeshedding regarding the default command/entrypoint:

• Setting the CMD to ["zstd"] allows to run:
  
  
  
  • docker run zstd for the default zstd command without parameters (simple)
  
  
  • docker run zstd zstd -9 for the zstd command with parameters (the repetition might be a bit weird)
  
  
  • docker run zstd zstdcat for other binaries (the repetition might be a bit weird here as well)
  
  
• Instead, setting the ENTRYPOING to ["zstd"] allows:
  
  
  
  • docker run zstd -9 to use the zstd command directly with parameters (looks good)
  
  
  • docker run --entrypoint zstdcat zstd for other binaries (the zstdcat/zstd inversion may look weird)
  
  

I'm not sure which of these two configurations is the most user-friendly one.

[Cyan4973]

maybe calling it zstd_image or anything else
would avoid the confusion with the executable name ?

[gyscos]

That's true; though the current standard is for images to have directly the name of the binary/service they provide: mysql, openjdk, ...

As a note, there's an unofficial lz4 image (though it doesn't appear to be very active, and has no documentation whatsoever). This one just sets a CMD to bash, so it needs to be called this way:

docker run sguthrie/lz4 lz4 -9

[Cyan4973]

I've been trying to use the proposed Dockerfile by @gyscos to create a docker image.

As a warning, my docker skills are pretty limited, so I'm merely copy/pasting suggested script in a local file called Dockerfile. I'm using Ubuntu LTS 16.04 as baseline for this test.

Attempt 1 :

$ docker build -t zstd .
Got permission denied while trying to connect to the Docker daemon socket

Attempt 2 :

$ sudo docker build -t zstd .
Sending build context to Docker daemon  2.56 kB
Step 1/9 : FROM alpine as builder
Error parsing reference: "alpine as builder" is not a valid repository/tag: invalid reference format

Also :

requires docker >= 17.05

$ docker -v
Docker version 1.13.1, build 092cba3

Versions do not match, but I'm wondering if these numbers are related.

[mkjaer]

1.13.1 is the old versioning scheme and is therefore older than 17.05.
Upgrading will allow you to build it.