I have the following docker file which downloads different things base on an argument passed in from docker-compose (either 2019 or 2022)
FROM mcr.microsoft.com/windows/servercore:ltsc2022
ARG VSVersion
SHELL ["powershell", "-Command", "$ErrorActionPreference = 'Stop'; $ProgressPreference = 'SilentlyContinue';"]
WORKDIR /Temp
SHELL ["cmd", "/S", "/C"]
RUN if [ "$VSVersion" == "2019" ]; then `
curl -SL --output vs_buildtools.exe https://aka.ms/vs/16/release/vs_buildtools.exe...
My issue is, the conditional run command is not working - it doesn't install in the above syntax.
I also tried using "%VSVersion%"=="2019" because it's default windows shell, but I get error: "2019"=="2019" was unexpected at this time.
Could someone please point me towards the right syntax because I've tried various combinations, with and without quotations, to no avail...
thanks
Dockerfile is in windows shell not bash, so change the if statement syntax to batch instead of bash:
RUN if "%VSVersion%"=="2019"( `
# Download the Build Tools bootstrapper.
curl -SL --output vs_buildtools.exe.. )
Related
Inside my Dockerfile:
ENV PROJECTNAME mytestwebsite
CMD ["django-admin", "startproject", "$PROJECTNAME"]
Error:
CommandError: '$PROJECTNAME' is not a valid project name
What is the quickest workaround here? Does Docker have any plan to "fix" or introduce this functionality in later versions of Docker?
NOTE: If I remove the CMD line from the Docker file and then run the Docker container, I am able to manually run Django-admin startproject $PROJECTNAME from inside the container and it will create the project...
When you use an execution list, as in...
CMD ["django-admin", "startproject", "$PROJECTNAME"]
...then Docker will execute the given command directly, without involving a shell. Since there is no shell involved, that means:
No variable expansion
No wildcard expansion
No i/o redirection with >, <, |, etc
No multiple commands via command1; command2
And so forth.
If you want your CMD to expand variables, you need to arrange for a shell. You can do that like this:
CMD ["sh", "-c", "django-admin startproject $PROJECTNAME"]
Or you can use a simple string instead of an execution list, which gets you a result largely identical to the previous example:
CMD django-admin startproject $PROJECTNAME
If you want to use the value at runtime, set the ENV value in the Dockerfile. If you want to use it at build-time, then you should use ARG.
Example :
ARG value
ENV envValue=$value
CMD ["sh", "-c", "java -jar ${envValue}.jar"]
Pass the value in the build command:
docker build -t tagName --build-arg value="jarName"
You also can use exec
This is the only known way to handle signals and use env vars simultaneously.
It can be helpful while trying to implement something like graceful shutdown according to Docker github
Example:
ENV PROJECTNAME mytestwebsite
CMD exec django-admin startproject $PROJECTNAME
Lets say you want to start a java process inside a container:
Example Dockerfile excerpt:
ENV JAVA_OPTS -XX +UnlockExperimentalVMOptions -XX:+UseCGroupMemoryLimitForHeap -XX:MaxRAMFraction=1 -XshowSettings:vm
...
ENTRYPOINT ["/sbin/tini", "--", "entrypoint.sh"]
CMD ["java", "${JAVA_OPTS}", "-myargument=true"]
Example entrypoint.sh excerpt:
#!/bin/sh
...
echo "*** Startup $0 suceeded now starting service using eval to expand CMD variables ***"
exec su-exec mytechuser $(eval echo "$#")
For the Java developers, following my solution below gonna work:
if you tried to run your container with a Dockerfile like below
ENTRYPOINT ["/docker-entrypoint.sh"]
# does not matter your parameter $JAVA_OPTS wrapped as ${JAVA_OPTS}
CMD ["java", "$JAVA_OPTS", "-javaagent:/opt/newrelic/newrelic.jar", "-server", "-jar", "app.jar"]
with an ENTRYPOINT shell script below:
#!/bin/bash
set -e
source /work-dir/env.sh
exec "$#"
it will build the image correctly but print the error below during the run of container:
Error: Could not find or load main class $JAVA_OPTS
Caused by: java.lang.ClassNotFoundException: $JAVA_OPTS
instead, Java can read the command line parameters either through the command line or by _JAVA_OPTIONS environment variable. so, it means we can pass the desired command line parameters through _JAVA_OPTIONS without changing anything on Dockerfile as well as to allow it to be able to start as parent process of container for the valid docker signalization via exec "$#".
The below one is my final version of the Dockerfile and docker-entrypoint.sh files:
...
ENTRYPOINT ["/docker-entrypoint.sh"]
CMD ["java", "-server", "-jar", "app.jar"]
#!/bin/bash
set -e
source /work-dir/env.sh
export _JAVA_OPTIONS="-XX:+PrintFlagsFinal"
exec "$#"
and after you build your docker image and tried to run it, you will see the logs below that means it worked well:
Picked up _JAVA_OPTIONS: -XX:+PrintFlagsFinal
[Global flags]
int ActiveProcessorCount = -1 {product} {default}
Inspired on above, I did this:
#snapshot by default. 1 is release.
ENV isTagAndRelease=0
CMD echo is_tag: ${isTagAndRelease} && \
if [ ${isTagAndRelease} -eq 1 ]; then echo "release build"; mvn -B release:clean release:prepare release:perform; fi && \
if [ ${isTagAndRelease} -ne 1 ]; then echo "snapshot build"; mvn clean install; fi && \
.....
I'm trying to do some basic containers in Windows. I've been using Docker on Linux for years, but this issue is new for me.
Running the command
docker build -f windowsTest3.df -t dockertest . results in a good, tagged build.
...
---> 04064df75127
Step 13/13 : ENTRYPOINT C:/BuildTools/Common7/Tools/VsDevCmd.bat
---> Using cache
---> 9e098cff37a2
Successfully built 9e098cff37a2
Successfully tagged dockertest:latest
However, attempting to run an interactive shell inside the container gives an error. The system cannot find the path specified.
Edit: Can't believe I forgot to list the command...
To start the container interactively, I'm running docker run -it dockertest, but I've also tried docker run -it dockertest cmd and variations of that.
Running docker images shows that the tagged image exists, so I can't figure out what's causing the error.
docker images
C:\Users\devuser.DESKTOP-UV8CO47\Desktop\tmp>docker images
REPOSITORY TAG IMAGE ID CREATED SIZE
dockertest latest 9e098cff37a2 41 minutes ago 12.3GB
Here are my path locations:
C:\ProgramData\DockerDesktop\version-bin;C:\Program Files\Docker\Docker\Resources\bin;C:\Program Files (x86)\Common Files\Oracle\Java\javapath;C:\Program Files (x86)\Python37-32\Scripts\;C:\Program Files (x86)\Python37-32\;C:\Windows\system32;C:\Windows;C:\Windows\System32\Wbem;C:\Windows\System32\WindowsPowerShell\v1.0\;C:\Windows\System32\OpenSSH\;C:\Program Files\Git\cmd;C:\Program Files (x86)\IAR Systems\Embedded Workbench 8.2\common\bin;C:\Program Files\Amazon\AWSCLI\bin\;C:\Program Files (x86)\GnuWin32\bin;C:\Program Files\CMake\bin;C:\Program Files\dotnet\;C:\Windows\Microsoft.NET\Framework\v4.0.30319;C:\ProgramData\chocolatey\bin;C:\PRQA\PRQA-Framework-2.4.0\common\bin;C:\Users\DevUser\AppData\Local\Microsoft\WindowsApps;C:\Program Files (x86)\IAR Systems\Embedded Workbench 8.2\arm\bin;C:\Program Files\Git\bin;C:\Program Files\7-Zip;C:\Program Files\nssm-2.24\win64
Here is a slightly abridged version of the dockerfile
FROM mcr.microsoft.com/windows:10.0.17763.316-amd64
# Restore the default Windows shell for correct batch processing.
SHELL ["cmd", "/S", "/C"]
# Download the Build Tools bootstrapper.
ADD https://aka.ms/vs/16/release/vs_buildtools.exe C:/tmp/vs_buildtools.exe
# Install Build Tools excluding workloads and components with known issues.
RUN C:/tmp/vs_buildtools.exe --quiet --wait --norestart --nocache \
--installPath C:\BuildTools \
--all \
--remove Microsoft.VisualStudio.Component.Windows10SDK.10240 \
--remove Microsoft.VisualStudio.Component.Windows10SDK.10586 \
--remove Microsoft.VisualStudio.Component.Windows10SDK.14393 \
--remove Microsoft.VisualStudio.Component.Windows81SDK \
|| IF "%ERRORLEVEL%"=="3010" EXIT 0
ENV chocolateyUseWindowsCompression=false
RUN powershell set-executionpolicy remotesigned
RUN powershell -Command Invoke-Expression ((New-Object Net.WebClient).DownloadString('https://chocolatey.org/install.ps1'))
RUN powershell -Command Install-PackageProvider -Name chocolatey -Force
RUN powershell -command "choco install -y git"
ENTRYPOINT C:/BuildTools/Common7/Tools/VsDevCmd.bat
Please check if VsDevCmd.bat is available inside the container when it's starting, at C:/BuildTools/Common7/Tools/ path
Also as per this Doc reference
On Windows, file paths specified in the CMD instruction must use
forward slashes or have escaped backslashes \.
CMD c:\Apache24\bin\httpd.exe -w
Maybe try your ENTRYPOINT like this.
ENTRYPOINT C:\\BuildTools\\Common7\\Tools\\VsDevCmd.bat
You can also use CMD
CMD C:\\BuildTools\\Common7\\Tools\\VsDevCmd.bat
Can also try this as well but recommended is above one
ENTRYPOINT C:\BuildTools\Common7\Tools\VsDevCmd.bat
I want to prepend something to the CLI passed in to a docker container.
I want it to run like this:
docker run -it mstools msbuild.exe --version
But, to make that work internally I need to prepend the full path the the msbuild.exe along with mono, like this:
mono /Microsoft.Build.Mono.Debug.14.1.0.0-prerelease/lib/msbuild.exe --version
When I use my below Dockerfile with the command, I get this:
$ docker run -it mstools msbuild.exe --version
msbuild.exe: 1: msbuild.exe: [/usr/bin/mono,: not found
If I jump into the container and check the path:
$ docker run -it --entrypoint=bash mstools
root#eb47008f092e:/# which mono
/usr/bin/mono
What am I missing??
Dockerfile:
FROM centeredge/nuget
ARG VERSION="14.1.0.0-prerelease"
RUN nuget install Microsoft.Build.Mono.Debug -Version $VERSION -Source "https://www.myget.org/F/dotnet-buildtools/"
ENV PATH="/Microsoft.Build.Mono.Debug.$VERSION/lib/:${PATH}"
ENTRYPOINT ['/usr/bin/mono', " /Microsoft.Build.Mono.Debug.$VERSION/lib/$1 $#"]
The error you get certainly comes from the fact you use single quotes ' instead of double quotes " in the ENTRYPOINT exec form.
In addition, I don't think the "$#" phrasing you mention will work (because "$#" needs some shell to evaluate it, while in the exec form there is no /bin/sh -c … implied). But the exec form of ENTRYPOINT is definitely the way to go.
So I'd suggest you write something like this:
FROM centeredge/nuget
ARG VERSION="14.1.0.0-prerelease"
RUN nuget install Microsoft.Build.Mono.Debug -Version $VERSION -Source "https://www.myget.org/F/dotnet-buildtools/"
ENV PATH="/Microsoft.Build.Mono.Debug.$VERSION/lib/:${PATH}"
COPY entrypoint.sh /usr/src/
RUN chmod a+x /usr/src/entrypoint.sh
ENTRYPOINT ["/usr/src/entrypoint.sh"]
with entrypoint.sh containing:
#!/bin/bash
exec /usr/bin/mono "/Microsoft.Build.Mono.Debug.$VERSION/lib/$1" "$#"
(Note: I didn't test this example code for now so please comment if you find some typo)
Final working solution based on #ErikMD's answer:
FROM centeredge/nuget
ARG VERSION="14.1.0.0-prerelease"
RUN nuget install Microsoft.Build.Mono.Debug -Version $VERSION -Source "https://www.myget.org/F/dotnet-buildtools/"
ENV PATH="/Microsoft.Build.Mono.Debug.$VERSION/lib/:/Microsoft.Build.Mono.Debug.$VERSION/lib/tools/:${PATH}"
RUN echo '#!/bin/bash' > /usr/src/entrypoint.sh && echo 'exec /usr/bin/mono "$(which "$1")" "$#"' >> /usr/src/entrypoint.sh && chmod a+x /usr/src/entrypoint.sh
ENTRYPOINT ["/usr/src/entrypoint.sh"]
output
docker run -it mstools MSBuild.exe -version
Microsoft (R) Build Engine version 14.1.0.0
Copyright (C) Microsoft Corporation. All rights reserved.
14.1.0.0
Inside my Dockerfile:
ENV PROJECTNAME mytestwebsite
CMD ["django-admin", "startproject", "$PROJECTNAME"]
Error:
CommandError: '$PROJECTNAME' is not a valid project name
What is the quickest workaround here? Does Docker have any plan to "fix" or introduce this functionality in later versions of Docker?
NOTE: If I remove the CMD line from the Docker file and then run the Docker container, I am able to manually run Django-admin startproject $PROJECTNAME from inside the container and it will create the project...
When you use an execution list, as in...
CMD ["django-admin", "startproject", "$PROJECTNAME"]
...then Docker will execute the given command directly, without involving a shell. Since there is no shell involved, that means:
No variable expansion
No wildcard expansion
No i/o redirection with >, <, |, etc
No multiple commands via command1; command2
And so forth.
If you want your CMD to expand variables, you need to arrange for a shell. You can do that like this:
CMD ["sh", "-c", "django-admin startproject $PROJECTNAME"]
Or you can use a simple string instead of an execution list, which gets you a result largely identical to the previous example:
CMD django-admin startproject $PROJECTNAME
If you want to use the value at runtime, set the ENV value in the Dockerfile. If you want to use it at build-time, then you should use ARG.
Example :
ARG value
ENV envValue=$value
CMD ["sh", "-c", "java -jar ${envValue}.jar"]
Pass the value in the build command:
docker build -t tagName --build-arg value="jarName"
You also can use exec
This is the only known way to handle signals and use env vars simultaneously.
It can be helpful while trying to implement something like graceful shutdown according to Docker github
Example:
ENV PROJECTNAME mytestwebsite
CMD exec django-admin startproject $PROJECTNAME
Lets say you want to start a java process inside a container:
Example Dockerfile excerpt:
ENV JAVA_OPTS -XX +UnlockExperimentalVMOptions -XX:+UseCGroupMemoryLimitForHeap -XX:MaxRAMFraction=1 -XshowSettings:vm
...
ENTRYPOINT ["/sbin/tini", "--", "entrypoint.sh"]
CMD ["java", "${JAVA_OPTS}", "-myargument=true"]
Example entrypoint.sh excerpt:
#!/bin/sh
...
echo "*** Startup $0 suceeded now starting service using eval to expand CMD variables ***"
exec su-exec mytechuser $(eval echo "$#")
For the Java developers, following my solution below gonna work:
if you tried to run your container with a Dockerfile like below
ENTRYPOINT ["/docker-entrypoint.sh"]
# does not matter your parameter $JAVA_OPTS wrapped as ${JAVA_OPTS}
CMD ["java", "$JAVA_OPTS", "-javaagent:/opt/newrelic/newrelic.jar", "-server", "-jar", "app.jar"]
with an ENTRYPOINT shell script below:
#!/bin/bash
set -e
source /work-dir/env.sh
exec "$#"
it will build the image correctly but print the error below during the run of container:
Error: Could not find or load main class $JAVA_OPTS
Caused by: java.lang.ClassNotFoundException: $JAVA_OPTS
instead, Java can read the command line parameters either through the command line or by _JAVA_OPTIONS environment variable. so, it means we can pass the desired command line parameters through _JAVA_OPTIONS without changing anything on Dockerfile as well as to allow it to be able to start as parent process of container for the valid docker signalization via exec "$#".
The below one is my final version of the Dockerfile and docker-entrypoint.sh files:
...
ENTRYPOINT ["/docker-entrypoint.sh"]
CMD ["java", "-server", "-jar", "app.jar"]
#!/bin/bash
set -e
source /work-dir/env.sh
export _JAVA_OPTIONS="-XX:+PrintFlagsFinal"
exec "$#"
and after you build your docker image and tried to run it, you will see the logs below that means it worked well:
Picked up _JAVA_OPTIONS: -XX:+PrintFlagsFinal
[Global flags]
int ActiveProcessorCount = -1 {product} {default}
Inspired on above, I did this:
#snapshot by default. 1 is release.
ENV isTagAndRelease=0
CMD echo is_tag: ${isTagAndRelease} && \
if [ ${isTagAndRelease} -eq 1 ]; then echo "release build"; mvn -B release:clean release:prepare release:perform; fi && \
if [ ${isTagAndRelease} -ne 1 ]; then echo "snapshot build"; mvn clean install; fi && \
.....
If I set an environment variable, say ENV ADDRESSEE=world, and I want to use it in the entry point script concatenated into a fixed string like:
ENTRYPOINT ["./greeting", "--message", "Hello, world!"]
with world being the value of the environment varible, how do I do it? I tried using "Hello, $ADDRESSEE" but that doesn't seem to work, as it takes the $ADDRESSEE literally.
You're using the exec form of ENTRYPOINT. Unlike the shell form, the exec form does not invoke a command shell. This means that normal shell processing does not happen. For example, ENTRYPOINT [ "echo", "$HOME" ] will not do variable substitution on $HOME. If you want shell processing then either use the shell form or execute a shell directly, for example: ENTRYPOINT [ "sh", "-c", "echo $HOME" ].
When using the exec form and executing a shell directly, as in the case for the shell form, it is the shell that is doing the environment variable expansion, not docker.(from Dockerfile reference)
In your case, I would use shell form
ENTRYPOINT ./greeting --message "Hello, $ADDRESSEE\!"
After much pain, and great assistance from #vitr et al above, i decided to try
standard bash substitution
shell form of ENTRYPOINT (great tip from above)
and that worked.
ENV LISTEN_PORT=""
ENTRYPOINT java -cp "app:app/lib/*" hello.Application --server.port=${LISTEN_PORT:-80}
e.g.
docker run --rm -p 8080:8080 -d --env LISTEN_PORT=8080 my-image
and
docker run --rm -p 8080:80 -d my-image
both set the port correctly in my container
Refs
see https://www.cyberciti.biz/tips/bash-shell-parameter-substitution-2.html
I tried to resolve with the suggested answer and still ran into some issues...
This was a solution to my problem:
ARG APP_EXE="AppName.exe"
ENV _EXE=${APP_EXE}
# Build a shell script because the ENTRYPOINT command doesn't like using ENV
RUN echo "#!/bin/bash \n mono ${_EXE}" > ./entrypoint.sh
RUN chmod +x ./entrypoint.sh
# Run the generated shell script.
ENTRYPOINT ["./entrypoint.sh"]
Specifically targeting your problem:
RUN echo "#!/bin/bash \n ./greeting --message ${ADDRESSEE}" > ./entrypoint.sh
RUN chmod +x ./entrypoint.sh
ENTRYPOINT ["./entrypoint.sh"]
I SOLVED THIS VERY SIMPLY!
IMPORTANT: The variable which you wish to use in the ENTRYPOINT MUST be ENV type (and not ARG type).
EXAMPLE #1:
ARG APP_NAME=app.jar # $APP_NAME can be ARG or ENV type.
ENV APP_PATH=app-directory/$APP_NAME # $APP_PATH must be ENV type.
ENTRYPOINT java -jar $APP_PATH
This will result with executing:
java -jar app-directory/app.jar
EXAMPLE #2 (YOUR QUESTION):
ARG ADDRESSEE="world" # $ADDRESSEE can be ARG or ENV type.
ENV MESSAGE="Hello, $ADDRESSEE!" # $MESSAGE must be ENV type.
ENTRYPOINT ./greeting --message $MESSAGE
This will result with executing:
./greeting --message Hello, world!
Please verify to be sure, whether you need quotation-marks "" when assigning string variables.
MY TIP: Use ENV instead of ARG whenever possible to avoid confusion on your part or the SHELL side.
For me, I wanted to store the name of the script in a variable and still use the exec form.
Note: Make sure, the variable you are trying to use is declared an environment variable either from the commandline or via the ENV directive.
Initially I did something like:
ENTRYPOINT [ "${BASE_FOLDER}/scripts/entrypoint.sh" ]
But obviously this didn't work because we are using the shell form and the first program listed needs to be an executable on the PATH. So to fix this, this is what I ended up doing:
ENTRYPOINT [ "/bin/bash", "-c", "exec ${BASE_FOLDER}/scripts/entrypoint.sh \"${#}\"", "--" ]
Note the double quotes are required
What this does is to allow us to take whatever extra args were passed to /bin/bash, and supply those same arguments to our script after the name has been resolved by bash.
man 7 bash
-- A -- signals the end of options and disables further
option processing. Any arguments after the -- are treated
as filenames and arguments. An argument of - is
equivalent to --.
In my case worked this way: (for Spring boot app in docker)
ENTRYPOINT java -DidMachine=${IDMACHINE} -jar my-app-name
and passing the params on docker run
docker run --env IDMACHINE=Idmachine -p 8383:8383 my-app-name
I solved the problem using a variation on "create a custom script" approach above. Like this:
FROM hairyhenderson/figlet
ENV GREETING="Hello"
RUN printf '#!/bin/sh\nfiglet -W \${GREETING} \$#\n' > /runme && chmod +x /runme
ENTRYPOINT ["/runme"]
CMD ["World"]
Run like
docker container run -it --rm -e GREETING="G'Day" dockerfornovices/figlet-greeter Alec
If someone wants to pass an ARG or ENV variable to exec form of ENTRYPOINT then a temp file created during image building process might be used.
In my case I had to start the app differently depending on whether the .NET app has been published as self-contained or not.
What I did is I created the temp file and I used its name in the if statement of my bash script.
Part of my dockerfile:
ARG SELF_CONTAINED=true #ENV SELF_CONTAINED=true also works
# File has to be used as a variable as it's impossible to pass variable do ENTRYPOINT using Exec form. File name allows to check whether app is self-contained
RUN touch ${SELF_CONTAINED}.txt
COPY run-dotnet-app.sh .
ENTRYPOINT ["./run-dotnet-app.sh", "MyApp" ]
run-dotnet-app.sh:
#!/bin/sh
FILENAME=$1
if [ -f "true.txt" ]; then
./"${FILENAME}"
else
dotnet "${FILENAME}".dll
fi
Here is what worked for me:
ENTRYPOINT [ "/bin/bash", "-c", "source ~/.bashrc && ./entrypoint.sh ${#}", "--" ]
Now you can supply whatever arguments to the docker run command and still read all environment variables.