Dotnet not found error when generating Dockerfile - docker

Question

I have a Gitlab-ci pipeline that should automatically generate a Dockerfile for a given .Net Core project if it does not already exist and after that execute a docker build.
I am getting an error when attempting to generate the Dockerfile :
section_end:1657538312:prepare_script
[0Ksection_start:1657538312:get_sources
[0K[0K[36;1mGetting source from Git repository[0;m[0;m
[32;1mFetching changes with git depth set to 20...[0;m
Initialized empty Git repository in /builds/demo/devops/labs/.git/
[32;1mCreated fresh repository.[0;m
[32;1mChecking out c2e2d044 as ingress...[0;m
[32;1mSkipping Git submodules setup[0;m
section_end:1657538314:get_sources
[0Ksection_start:1657538314:download_artifacts
[0K[0K[36;1mDownloading artifacts[0;m[0;m
[32;1mDownloading artifacts for publish_job (36805)...[0;m
Downloading artifacts from coordinator... ok [0;m id[0;m=36805 responseStatus[0;m=200 OK token[0;m=-1ETTroN
section_end:1657538315:download_artifacts
[0Ksection_start:1657538315:step_script
[0K[0K[36;1mExecuting "step_script" stage of the job script[0;m[0;m
[32;1m$ dotnet restore --packages $NUGET_PACKAGES_DIRECTORY[0;m
/scripts-1175-36806/step_script: eval: line 118: dotnet: not found
section_end:1657538316:step_script
[0Ksection_start:1657538316:cleanup_file_variables
[0K[0K[36;1mCleaning up project directory and file based variables[0;m[0;m
section_end:1657538316:cleanup_file_variables
[0K[31;1mERROR: Job failed: command terminated with exit code 127
[0;m
However the dotnet command executes well in the publish stage. I am not sure why dotnet is not being recognized in the docker context.
The pipeline:
before_script:
- 'dotnet restore --packages $NUGET_PACKAGES_DIRECTORY'
build_job:
tags:
- labs
only:
- develop
- ingress
stage: build
script:
- dotnet build --configuration Release --no-restore
publish_job:
tags:
- labs
only:
- develop
- ingress
stage: publish
artifacts:
name: "$CI_COMMIT_SHA"
paths:
- ./$PUBLISH_DIR
script:
- dotnet publish ./src --configuration Release --output $(pwd)/$PUBLISH_DIR
docker_build_dev:
tags:
- labs
image:
name: gcr.io/kaniko-project/executor:v1.6.0-debug
entrypoint: [""]
only:
- develop
- ingress
stage: docker
script: |
echo "checking dockerfile existence"
if ! [ -e Dockerfile ]; then
echo "dockerfile doesn't exist. Trying to create a new dockerfile from csproj."
docker_entrypoint=$(grep -m 1 AssemblyName ./src/*.csproj | sed -r 's/\s*<[^>]*>//g' | sed -r 's/\r$//g').dll
cat > Dockerfile << EOF
FROM mcr.microsoft.com/dotnet/aspnet:6.0 AS base
RUN dotnet --version
WORKDIR /app
COPY ./publish .
ENTRYPOINT dotnet $docker_entrypoint
EOF
echo "dockerfile created"
else
echo "dockerfile exists"
fi
What am I missing ?

Answer 1

eval: line 118: dotnet: not found
It looks like you haven't defined an image: for this job and whatever default image you are using does not have dotnet installed (or if you're using a shell runner, your runner system does not have dotnet installed/on PATH).
To address this, you should either (1) specify an image: that has dotnet available (or install it on your runner if using a shell runner and ensure it is on PATH) or (2) install dotnet as part of your job.
For example:
myjob:
image: mcr.microsoft.com/dotnet/sdk
# ...
Alternatively, you can use a dotnet install script to install dotnet in your job.