Cannot find main module; see 'go help modules' - docker

I am building a Wasm application and to compile it I have a shell script.
When I run it manually from terminal I have the following:
/app/Go/assets$ ./script.compile.wasm.sh
Wasm compiled
The content of the file is:
#!/bin/sh
GOOS=js GOARCH=wasm go build -o ./app.wasm ./wasm.go
echo "Wasm compiled"
The wasm file is properly compiled.
But when I run it from Docker I get:
Step 15/20 : RUN ./assets/compile.wasm.sh
---> Running in 38dd56259b0f
go: cannot find main module; see 'go help modules'
Wasm compiled
The compilation fails.
The Docker line looks like:
RUN ./assets/compile.wasm.sh

In your local case, you're launching the script from the assets directory; in the Dockerfile case you're launching it from its parent directory. This matters because when the script references files like ./wasm.go, those are resolved relative to the current directory and not the directory containing the script.
You can resolve this by making sure you're in the assets directory in the Dockerfile too:
# Only for this command; will reset afterwards
RUN cd assets && ./compile.wasm.sh
# For this and all following commands, unless reset with another WORKDIR
WORKDIR /app/Go/assets
RUN ./compile.wasm.sh

Related

Using JMeter plugins with justb4/jmeter Docker image results in error

Goal
I am using Docker to run JMeter in Azure Devops. I am trying to use Blazemeter's Parallel Controller, which is not native to JMeter. So, according to the justb4/jmeter image documentation, I used the following command to get the image going and run the JMeter test:
docker run --name jmetertest -i -v /home/vsts/work/1/s/plugins:/plugins -v $ROOTPATH:/test -w /test justb4/jmeter ${#:2}
Error
However, it produces the following error while trying to accommodate for the plugin (I know the plugin makes the difference due to testing without the plugin):
cp: can't create '/test/lib/ext': No such file or directory
As far as I understand, this is an error produced when one of the parent directories of the directory you are trying to make does not exist. Is there something I am doing wrong, or is there actually something wrong with the image?
References
For reference, I will include links to the image documentation and the repository.
Image: https://hub.docker.com/r/justb4/jmeter
Repository: https://github.com/justb4/docker-jmeter
Looking into the Dockerfile:
ENV JMETER_HOME /opt/apache-jmeter-${JMETER_VERSION}
Looking into entrypoint.sh
if [ -d /plugins ]
then
for plugin in /plugins/*.jar; do
cp $plugin $(pwd)/lib/ext
done;
fi
It basically copies the plugins from /plugins folder (if it is present) to /lib/ext folder relative to current working directory
I don't know why did you add this stanza -w /test to your command line but it explicitly "tells" the container that local working directory is /test, not /opt/apache-jmeter-xxxx, that's why the script is failing to copy the files.
In general I don't think that the approach is very valid because:
In Azure DevOps you won't have your "local" folder (unless you want to add plugins binaries under the version control system)
Some JMeter Plugins have other .jars as the dependencies so when you're installing the plugin you should:
put the plugin itself under /lib/ext folder of your JMeter installation
put the plugin dependencies under /lib folder of your JMeter installation
So I would recommend amending the Dockerfile, download JMeter Plugins Manager and installed the plugin(s) you need from the command line
Something like:
RUN wget https://jmeter-plugins.org/get/ -O /opt/apache-jmeter-${JMETER_VERSION}/lib/ext/jmeter-plugins-manager.jar
RUN wget https://repo1.maven.org/maven2/kg/apc/cmdrunner/2.2/cmdrunner-2.2.jar -P /opt/apache-jmeter-${JMETER_VERSION}/lib/
RUN java -cp /opt/apache-jmeter-${JMETER_VERSION}/lib/ext/jmeter-plugins-manager.jar org.jmeterplugins.repository.PluginManagerCMDInstaller
RUN /opt/apache-jmeter-${JMETER_VERSION}/bin/./PluginsManagerCMD.sh install bzm-parallel

Can I use WORKDIR in my Dockerfile with Github Actions? (Also, resolving Jest "No tests found")

Can I use WORKDIR in my Dockerfile with Github Actions?
I am switching from one CI provider to Github Actions and found that I had a step that runs docker run <temp_image> npm test -- --coverage and something seemed to be altering the way my Jest test were run, compared to my previous CI, and I would receive the error:
No tests found, exiting with code 1
Run with `--passWithNoTests` to exit with code 0
In /app
18 files checked.
testMatch: /**/?(*.)+(spec|test).[jt]s?(x) - 1 match
testPathIgnorePatterns: /.next/, /node_modules/, /testconfig/ - 16 matches
testRegex: - 0 matches
Pattern: - 0 matches
That one testMatch would run correctly in my previous CI solution, using the same command.
Some with this error were accidentally ignoring their test path : Jest No Tests found
I tried a bunch of different approaches -- the main hunch being that my tests were being run in the incorrect directory. Using my shotgun approach I tried:
Specifying <rootdir> for testMatch and testPathIgnorePatterns
Removing testPathIgnorePatterns altogether
Specifying the --config path, also --no-cache, options for Jest
Specifying the -w working directory on docker run options
And a multi-command approach for docker run /bin/sh/ (cd /app && npm test)
Ultimately, I found this line in Github Actions Docs: Dockerfile Instructions And Overrides
GitHub sets the working directory path in the GITHUB_WORKSPACE environment variable. It's recommended to not use the WORKDIR instruction in your Dockerfile.
Removing the WORKDIR instruction in my Dockerfile fixes my error
BUT, Is there a way around having to remove WORKDIR from my Dockerfile? It seems to maybe be a Docker best practice to use WORKDIR and I would prefer to follow Docker guidelines than Github Actions.
Thank you for your time!

Creating a dockerfile to compile source code

I am trying to follow the 2 steps mentioned below:
1) Downloaded source code of
https://sourceforge.net/projects/hunspell/files/Hyphen/2.8/hyphen-2.8.8.tar.gz/download
2) Compiled it and you will get binary named example:
hyphen-2.8.8$ ./example ~/dev/smc/hyphenation/hi_IN/hyph_hi_IN.dic
~/hi_sample.text
I have downloaded and uncompressed the tar file. My question is how to create a dockerfile to automate this?
There are only 3 commands involved:
./configure
make all-recursive
make install
I can select the official python image as a base container. But how do I write the commands in a docker file?
You can do that with a RUN command:
FROM python:<version number here>
RUN ./configure && make-recursive && make install
CMD ['<some command here>']
what you use for <some command here> depends on what the image is meant to do. Remember that docker containers only run as long as that command is executing, so if you put the configure/make/install steps in a script and use that as your entry point, it's going to build your program, and then the container will halt.
Also you need to get the downloaded files into the container. That can be done using a COPY or an ADD directive (before the RUN of course). If you have the tar.gz file saved locally, then ADD will both copy the file into the container and expand it into a directory automatically. COPY will not expand it, so if you do that, you'll need to add a tar -zxvf or similar to the RUN.
If you want to download the file directly into the container, that could be done with ADD <source URL>, but in that case it won't expand it, so you'll have to do that in the RUN. COPY doesn't allow sourcing from a URL. This post explains COPY vs ADD in more detail.
You can have the three commands in a shell script and then use the following docker commands
COPY ./<path to your script>/<script-name>.sh /
ENTRYPOINT ["/<script-name>.sh"]
CMD ["run"]
For reference, you can create your docker file as they have created for one of the projects I worked on Apache Artemis Active Mq:
https://github.com/apache/activemq-artemis/blob/master/artemis-docker/Dockerfile-ubuntu

How do I make cmake only build the executable for docker?

If I build a cmake file, create an executeble with make and delete everything except the executable, the executable is still functional. Can I,
build the file but the only output is the file that can be executed with ./project
or
have all of the files build, create the executable with make, then delete everything except the executable afterwards
and if so, how do I?
If I am getting this correctly, you want to create a stand-alone binary that cannot be executed even if the docker image does not has any dependencies then you need to use static option during the build - i am not expert in this - maybe as described in the following answer of Compiling a static executable with CMake.
Next you might use a multi-stage builds in docker which will makes you able to have a final minimal image with your executable file only without any build dependencies, just the needed packages for your run-time environment. I have an example not with make, it was created using g++ but achieving the similar concept as below:
FROM gcc:5 as builder
COPY ./hello_world_example.cc /hello_world_example.cc
RUN g++ -o hello_world_binary -static hello_world_example.cc && chmod +x hello_world_binary
FROM debian:jessie
COPY --from=builder /hello_world_binary /hello_world_binary
CMD ["/hello_world_binary"]
And the final result when you run the container:
$ docker run --rm -it helloworldimage:latest
Hello from Dockerized image
Why do you need that?
You can add install() command to your CMakeLists.txt and then call make install to copy your executable into CMAKE_INSTALL_PREFIX directory. If you set CMAKE_INSTALL_PREFIX to an empty dir, you'd end with a directory containing only your executable file.

Dockerhub automated build fails, "not a directory" when adding file

I am trying to use docker hub to automatically build something that builds fine locally. It fails saying:
Build process failed: stat /var/lib/docker/aufs/mnt/1be9db483fa6f3de2596b5261e7c450de8df503185e579278396f14ba179c257/bin/run.sh: not a directory
You can view the build itself here:
https://hub.docker.com/r/zbyte64/rethinkdb-tlsproxy/builds/bjclhq33kgwxxvn6nbfsgyh/
run.sh is in the same directory as Dockerfile, it seems the build path on dockerhub is different then where it stores the Dockerfile.
I have tried the following variations:
COPY run.sh /bin
ADD ./run.sh /bin
The COPY command (on Dockerhub's Docker version) expects the target file on the right hand side, not just the target directory. The following command should work for you even on Dockerhub.
COPY run.sh /bin/run.sh
Or if you want to use ADD, include the trailing slash.
ADD ./run.sh /bin/
What is actually happening? From https://docs.docker.com/engine/reference/builder/#add :
ADD src dest
"If dest does not end with a trailing slash, it will be considered a regular file and the contents of src will be written at dest."
Without the trailing slash on /bin, it expects run.sh to be a directory being copied to directory /bin.
I don't know why, but dockerhub wants the first argument of COPY or ADD to be a directory - not a file. I am running Docker 1.9.1 locally and that is not the case. I switched the Dockerfile to copy a resource directory instead of individual files and things started to work.

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