I need to initialize environment variables when running a container by the script.
So write a shell script to initialize it when running a container by assign it to entrypoint.
entrypoint.sh
#!/bin/bash
# Load the script of environment variables
. /home/foo/setupvars.sh
echo "INITIALIZZEE"
printenv
exec "$#"
Dockerfile
FROM ubuntu:18.04
WORKDIR /home/foo
COPY entrypoint.sh /home/foo/entrypoint.sh
RUN ["chmod", "+x", "/home/foo/entrypoint.sh"]
COPY setupvars.sh /home/foo/setupvars.sh
RUN ["chmod", "+x", "/home/foo/setupvars.sh"]
ENTRYPOINT ["/home/foo/entrypoint.sh"]
setupvars.sh
I build the image,
docker build -t foo .
and run a container like:
docker run --rm -it foo bash
When run a container, environment variable script run, echo run, printenv run. But I can't get any interactive bash. exec "$#" commands can't get my bash command. When I write there manually bash like exec "bash", it works.. On the other hand, it can't.
My steps are same in the best practices of docker.
What is my mistake?
As I see, the arguments lose when run another script in entrypoint.sh
So before run it, assign the arguments to a variable.
#!/bin/bash
# to save arguments assign them a variable before running script below
COM=$#
# Load the script of environment variables
. /opt/intel/openvino/bin/setupvars.sh
# export LD_LIBRARY_PATH=/usr/local/lib/:$LD_LIBRARY_PATH
# export PYTHONPATH=/usr/local/lib/python3.6/dist-packages/:$PYTHONPATH
echo "INITIALIZZEE"
printenv
# Run the main container command
exec $COM
Related
Is it possible to conditionally set an ENV variable in a Dockerfile based on the value of a build ARG?
Ex: something like
ARG BUILDVAR=sad
ENV SOMEVAR=if $BUILDVAR -eq "SO"; then echo "hello"; else echo "world"; fi
Update: current usage based on Mario's answer:
ARG BUILD_ENV=prod
ENV NODE_ENV=production
RUN if [ "${BUILD_ENV}" = "test" ]; then export NODE_ENV=development; fi
However, running with --build-arg BUILD_ENV=test and then going onto the host, I still get
docker run -it mycontainer bin/bash
[root#brbqw1231 /]# echo $NODE_ENV
production
Yes, it is possible, but you need to use your build argument as flag. You can use parameter expansion feature of shell to check condition. Here is a proof-of-concept Docker file:
FROM debian:stable
ARG BUILD_DEVELOPMENT
# if --build-arg BUILD_DEVELOPMENT=1, set NODE_ENV to 'development' or set to null otherwise.
ENV NODE_ENV=${BUILD_DEVELOPMENT:+development}
# if NODE_ENV is null, set it to 'production' (or leave as is otherwise).
ENV NODE_ENV=${NODE_ENV:-production}
Testing build:
docker build --rm -t env_prod ./
...
docker run -it env_prod bash
root#2a2c93f80ad3:/# echo $NODE_ENV
production
root#2a2c93f80ad3:/# exit
docker build --rm -t env_dev --build-arg BUILD_DEVELOPMENT=1 ./
...
docker run -it env_dev bash
root#2db6d7931f34:/# echo $NODE_ENV
development
You cannot run bash code in the Dockerfile directly, but you have to use the RUN command. So, for example, you can change ENV with RUN and export the variable in the if, like below:
ARG BUILDVAR=sad
RUN if [ "$BUILDVAR" = "SO" ]; \
then export SOMEVAR=hello; \
else export SOMEVAR=world; \
fi
I didn't try it but should work.
Your logic is actually correct.
The problem here is that RUN export ... won't work in a Dockerfile because the export command won't persist across images.
Dockerfiles create a temporary container in order to generate the image for it, therefore the environment variables won't exist.
ENV on the other hand as per the documentation states:
The environment variables set using ENV will persist when a container is run from the resulting image.
The only way to do this is during your docker run command when generating the container from your image, and wrap your logic around that:
if [ "${BUILD_ENV}" = "test" ]; then
docker run -e NODE_ENV=development myimage
else
docker run myimage
fi
While you can't set conditional ENV variables but you may be able to acomplish what you are after with the RUN command and a null-coalescing environment variable:
RUN node /var/app/current/index.js --env ${BUILD_ENV:-${NODE_ENV:-"development"}}
If we are talking only about environment variable, then just set it with production
ENV NODE_ENV prod
And during container start in development, you may use -e NODE_ENV=dev.
This way image is always built-in production but the local container is launched in development.
This answer is great if you only need to check whether a build-arg is present and you want to set a default value.
To improve this solution, in case you want to use the data passed by the build-arg, you can do the following:
FROM debian:stable
ARG BUILD_DEVELOPMENT=production
ENV NODE_ENV=$BUILD_DEVELOPMENT
The magic comes from the default value for the ARG.
Passing values to Dockerfile and then to entrypoint script
From the command line pass in your required value (TARG)
docker run --env TARG=T1_WS01 -i projects/msbob
Then in your Dockerfile put something like this
Dockerfile:
# if $TARG is not set then "entrypoint" defaults to Q0_WS01
CMD ./entrypoint.sh ${TARG} Q0_WS01
The entrypoint.sh script only reads the first argument
entrypoint.sh:
#!/bin/bash
[ $1 ] || { echo "usage: entrypoint.sh <$TARG>" ; exit ; }
target_env=$1
I had a similar issue for setting proxy server on a container.
The solution I'm using is an entrypoint script, and another script for environment variables configuration. Using RUN, you assure the configuration script runs on build, and ENTRYPOINT when you run the container.
--build-arg is used on command line to set proxy user and password.
The entrypoint script looks like:
#!/bin/bash
# Load the script of environment variables
. /root/configproxy.sh
# Run the main container command
exec "$#"
configproxy.sh
#!/bin/bash
function start_config {
read u p < /root/proxy_credentials
export HTTP_PROXY=http://$u:$p#proxy.com:8080
export HTTPS_PROXY=https://$u:$p#proxy.com:8080
/bin/cat <<EOF > /etc/apt/apt.conf
Acquire::http::proxy "http://$u:$p#proxy.com:8080";
Acquire::https::proxy "https://$u:$p#proxy.com:8080";
EOF
}
if [ -s "/root/proxy_credentials" ]
then
start_config
fi
And in the Dockerfile, configure:
# Base Image
FROM ubuntu:18.04
ARG user
ARG pass
USER root
# -z the length of STRING is zero
# [] are an alias for test command
# if $user is not empty, write credentials file
RUN if [ ! -z "$user" ]; then echo "${user} ${pass}">/root/proxy_credentials ; fi
#copy bash scripts
COPY configproxy.sh /root
COPY startup.sh .
RUN ["/bin/bash", "-c", ". /root/configproxy.sh"]
# Install dependencies and tools
#RUN apt-get update -y && \
# apt-get install -yqq --no-install-recommends \
# vim iputils-ping
ENTRYPOINT ["./startup.sh"]
CMD ["sh", "-c", "bash"]
Build without proxy settings
docker build -t img01 -f Dockerfile .
Build with proxy settings
docker build -t img01 --build-arg user=<USER> --build-arg pass=<PASS> -f Dockerfile .
Take a look here.
FROM alpine:3.11
COPY out/ /bin/
CMD ["command", "--flag1", "${HOST}", "--flag2", "${PORT}", "--flag3", "${AUTH_TOKEN}"]
This is the docker file used. I am loading the env variables during run through an env file.
But the variables are not substituted when running the command. If I override the CMD and exec into the container I am able to see the envs though.
What am I missing here?
You are running CMD in exec mode. Switch to shell mode and it will work out. As for the environment variables to be present you need a shell. more reading
your example:
CMD command --flag1 ${HOST} --flag2 ${PORT} --flag3 ${AUTH_TOKEN}
Full generic example:
Dockerfile:
FROM debian:stretch-slim
CMD echo ${env}
Run:
docker build .
docker run --rm -e env=hi <image id from build step>
hi
I have a Dockerfile as follows.
ENV SPRING_ENV="local"
ENV APP_OPTS "-Xmx8144m"
RUN echo "/usr/lib/jvm/java-1.8-openjdk/bin/java ${APP_OPTS} -Djava.security.egd=file:/dev/./urandom -jar /apps/demo/demo-fe.jar --spring.config.location=file:///apps/demo/conf/ump.properties -Dspring.profiles.active=${SPRING_ENV} &" > /apps/demo/entrypoint.sh
RUN chmod +x /apps/demo/entrypoint.sh
When I run the dockerfile, I see a file 'entrypoint.sh' with the java command that I specified in the Dockerfile.
But I want to change the java max memory depending on the environment. So I am running like this.
docker run -it <image_id> sh -e "APP_OPTS=-Xmx9144m" -e "SPRING_ENV=dev"
But when I run it, i check the entrypoint.sh, i don't see the environment variables replaced. Am I missing something?
Does it replace only on the fly when I actually run the container?
You need to escape the $ in ${APP_OPTS} (i.e., change it to \${APP_OPTS}) -- during docker build, the variable is getting replaced with the "current" environment variable, which would be whatever is in your env output (otherwise null). Calling docker run ... -e "APP_OPTS=-Xmx9144m" won't do anything at this point because ${APP_OPTS} has been replaced after the image was created.
Otherwise, you could try saving the entrypoint.sh file and put it in the same folder as your Dockerfile instead of having your Dockerfile create it (and use COPY instead to put it where you want it). That way, the ${APP_OPTS} environment variable won't get replaced during docker build
The Dockerfile (and the RUN command) are only executed when you build the image. SPRING_ENV and APP_UMPFE_OPTS are being evaluated only once and during the build.
When you run the image, the --env=KEY=VALUE are passed to the shell (!) running the process defined in the ENTRYPOINT or CMD (which you need but do not have).
You're missing a FROM ... statement near the top of the Dockerfile too.
You will need to define (recommend the shell-form of) ENTRYPOINT that invokes the java runtime, passes the environment variables and runs your code, perhaps (have not tried this):
FROM ???
ENV SPRING_ENV="local"
ENV APP_OPTS "-Xmx8144m"
ENTRYPOINT /usr/lib/jvm/java-1.8-openjdk/bin/java ${APP_OPTS} -Djava.security.egd=file:/dev/./urandom -jar /apps/demo/demo-fe.jar --spring.config.location=file:///apps/demo/conf/ump.properties -Dspring.profiles.active=${SPRING_ENV}
Example:
FROM busybox
ENV DOG=Freddie
ENTRYPOINT echo ${DOG}
Then:
docker build --tag=58208029 --file=./Dockerfile .
docker run -it 58208029:latest
Freddie
docker run -it --env=DOG=Henry 58208029:latest
Henry
HTH!
The entrypoint.sh is being written when you build the image, so that RUN statement won't be executed again when you run the container. So the entrypoint.sh file itself will not be updated.
Another issue is that when you do the docker run, the -e options need to be before the image name and command:
docker run -it -e "APP_OPTS=-Xmx9144m" -e "SPRING_ENV=dev" <image_id> sh
Otherwise those are just being passed as arguments to the entrypoint/command
Also, in your Dockerfile, you probably want single quotes around your entrypoint script so that it doesn't interpolate the values at build time.
RUN echo '/usr/lib/jvm/java-1.8-openjdk/bin/java ${APP_OPTS} -Djava.security.egd=file:/dev/./urandom -jar /apps/demo/demo-fe.jar --spring.config.location=file:///apps/demo/conf/ump.properties -Dspring.profiles.active=${SPRING_ENV} &' > /apps/demo/entrypoint.sh
Then when you run the container, the entrypoint script should read the variable values at run time from the environment.
I am trying to do the following:
Pass a build arg to my docker build command
Store that as an env variable in my container
Use it in my CMD to start when my container launches.
Below is my setup:
FROM ubuntu:xenial
ARG EXECUTABLE
ENV EXECUTABLE ${EXECUTABLE}
CMD ["/opt/foo/bin/${EXECUTABLE}", "-bar"]
Here is how i'm building container
docker build --build-arg EXECUTABLE=$EXECUTABLE -t test_image .
Here is how i'm running image
docker run -d test_image
When I run the container it crashes and tells me
docker: Error response from daemon: OCI runtime create failed:
container_linux.go:296: starting container process caused
"exec: \"/opt/foo/bin/${EXECUTABLE}\": stat /opt/foo/bin/${EXECUTABLE}:
no such file or directory": unknown.
To use environment variables, you need to use shell.
https://docs.docker.com/engine/reference/builder/#cmd
Note: Unlike the shell form, the exec form does not invoke a command
shell. This means that normal shell processing does not happen. For
example, CMD [ "echo", "$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: CMD [ "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.
Based on this, I think you can work fine by the following Dockerfile.
FROM ubuntu:xenial
ARG EXECUTABLE
ENV EXECUTABLE ${EXECUTABLE}
CMD [ "sh", "-c", "/opt/foo/bin/${EXECUTABLE}", "-bar"]
You'll have to write out an executable or shim as ARG / ENV substitution is not supported for CMD.
The list of supported substitutions:
ADD
COPY
ENV
EXPOSE
FROM
LABEL
STOPSIGNAL
USER
VOLUME
WORKDIR
as well as:
ONBUILD (when combined with one of the supported instructions above)
A workaround is to write your executable to a file and execute that:
FROM ubuntu:xenial
ARG EXECUTABLE
RUN : \
&& /bin/echo -e "#!/bin/sh\nexec '/bin/$EXECUTABLE' -bar" > /exe \
&& chmod +x /exe
CMD ["/exe"]
Build:
docker build -t test --build-arg EXECUTABLE=echo .
Run:
$ docker run -ti test
-bar
Another way to access the environment variable passed is by running it as:
docker run -e EXECUTABLE=<some_value> <docker_image>
Then, in the dockerfile
CMD exec /opt/foo/bin/${EXECUTABLE} -bar
Using Docker for Windows, Community version 17.06.0-ce-win19 (12801), Windows 10
Dockerfile
FROM frolvlad/alpine-oraclejdk8:slim
ARG APP_NAME=client-default
RUN mkdir -p /client/
ADD build/libs/$APP_NAME.jar /client/$APP_NAME.jar
ENTRYPOINT ["java", "-jar", "/client/$APP_NAME.jar"]
Running
docker build --build-arg APP_NAME=client-1 -t test/client-1 .
Placeholders not replaced after build (tried ${APP_NAME}, %APP_NAME%)
ARG and ENV are not replaced by Docker in an ENTRYPOINT or a CMD when you use the EXEC form inside []. If the ENTRYPOINT or CMD use the shell form (string, not an array) the shell will be able to do the variable substitution for you.
ARG and ENV variables will be available in RUN commands in the container as environment variables.
Docker will also replace $VARIABLES in the Dockerfile in the following instructions:
ADD
COPY
ENV
EXPOSE
FROM
LABEL
STOPSIGNAL
USER
VOLUME
WORKDIR
Only ENV variables will become available in a CMD or ENTRYPOINT, only in the environment of the running container:
Using ARG
FROM frolvlad/alpine-oraclejdk8:slim
ARG APP_NAME=client-default
ENV APP_NAME=$APP_NAME
RUN mkdir -p /client/
ADD build/libs/$APP_NAME.jar /client/$APP_NAME.jar
ENTRYPOINT ["sh", "-c", "java -jar /client/$APP_NAME.jar"]
or with only ENV
FROM frolvlad/alpine-oraclejdk8:slim
ENV APP_NAME=client-default
RUN mkdir -p /client/
ADD build/libs/$APP_NAME.jar /client/$APP_NAME.jar
ENTRYPOINT ["sh", "-c", "java -jar /client/$APP_NAME.jar"]
Environment variables in Dockerfile are declared with the ENV statement.
In your case:
FROM frolvlad/alpine-oraclejdk8:slim
ENV APP_NAME client-default
RUN mkdir -p /client/
ADD build/libs/${APP_NAME}.jar /client/${APP_NAME}.jar
ENTRYPOINT ["java", "-jar", "/client/${APP_NAME}.jar"]
ARG is only available during the build of a Docker image (RUN etc), not after the image is created and containers are started from it (ENTRYPOINT OR CMD)
ARG variable doesn't get substituted in Dockerfile. ARG IS really an environment variable. During the build, docker "runs" the container using ARG variables as environment variables. Easy to prove (you can test it): Try RUN printenv on your Dockerfile and you'll see the ARG as environment variable
So, you've got two problems:
First:
The Steps in console DOESN'T substitute the ARG variable. So, your jar is really in the container, your line:
ADD build/libs/$APP_NAME.jar /client/$APP_NAME.jar
it's working. Try it.
Second:
Entrypoint is for the running container, not for the image, so you need to put your ARG into an ENV variable, and not to use the exec form. If your use the exec form of ENTRYPOINT does not invoke a command shell. This means that normal shell processing does not happen. If you want shell processing then either use the shell form or execute a shell directly, for example:
ENTRYPOINT cat ${APP_NAME_RUN}
So, try this working example:
FROM ubuntu
ARG APP_NAME=client
RUN mkdir -p /client/
ADD ./$APP_NAME.txt /client/$APP_NAME.txt
ENV APP_NAME_RUN="/client/${APP_NAME}.txt"
RUN echo $APP_NAME_RUN
ENTRYPOINT cat ${APP_NAME_RUN}