I have a Dockerfile as shown below:
FROM centos:centos6
MAINTAINER tapash
###### Helpful utils
RUN yum -y install sudo
RUN yum -y install curl
RUN yum -y install unzip
#########Copy hibernate.cfg.xml to Client
ADD ${hibernate_path}/hibernate.cfg.xml /usr/share/tomcat7/webapps/roc_client/WEB-INF/classes/
I need a command line argument to be passed during docker build to be specified for the $hibernate_path.
How do I do this?
If this is purely a build-time variable, you can use the --build-arg option of docker build.
This flag allows you to pass the build-time variables that are accessed like regular environment variables in the RUN instruction of the Dockerfile. Also, these values don’t persist in the intermediate or final images like ENV values do.
docker build --build-arg hibernate_path=/a/path/to/hibernate -t tag .
In 1.7, only the static ENV Dockerfile directive is available.
So one solution is to generate the Dockerfile you need from a template Dockerfile.tpl.
Dockerfile.tpl:
...
ENV hibernate_path=xxx
ADD xxx/hibernate.cfg.xml /usr/share/tomcat7/webapps/roc_client/WEB-INF/classes/
...
Whenever you want to build the image, you generate first the Dockerfile:
sed "s,xxx,${hibernate_path},g" Dockerfile.tpl > Dockerfile
Then you build normally: docker build -t myimage .
You then benefit from (in docker 1.7):
build-time environment substitution
run-time environment variable.
You create a script that puts in your Dockerfile the required value and launches docker build -t mytag .
Related
This question is a little like this question. How to pass GitLab CI file variable to Dockerfile and docker container?
I used the most voted answer however I failed.
The below is what I want to do.
I set up the gitlab ci variable called PIP_CONFIG with file type.
and the value is like
[global]
timeout = 60
in .gitlab-ci.yml
...
- docker build -t $IMAGe
--build-arg PIP_CONFIG=$PIP_CONFIG
src/.
...
in Dockerfile
FROM python:3
ARG PIP_CONFIG
RUN mkdir ~/.pip
RUN echo $PIP_CONFIG > ~/.pip/pip.conf
...
...
RUN pip install -r requirements.txt
And then I got an error
Configuration file could not be loaded.
File contains no section headers.
file: '/root/.pip/pip.conf', line: 1
'/builds/xxx/xxx/project_name.tmp/PIPCONFIG\n' <<<< this line
...
It seems like it only wrote the path of temp file rather than the content of file.
I also try use COPY $PIP_CONFIG ~/.pip/pip.conf but it said the path is not exsist in /builds/xxx/xxx/project_name.tmp/PIPCONFIG.
Could someone tell me what should I do correctly? Thanks.
PS: The reason why I do not write the config directly in repository and jus use COPY from repo is that there is some sensitive token in pip config.
After some try, I understand that just use type 'variable' in the gitlab ci setting.
And then pass the value with quote("$VARABLE") for maybe you have the space or break line in your value.
like this
in .gitlab-ci.yml
...
- docker build -t $IMAGe
--build-arg PIP_CONFIG="$PIP_CONFIG"
src/.
...
Remember add quote for Dockerfile, too.
FROM python:3
ARG PIP_CONFIG
RUN mkdir ~/.pip
RUN echo "$PIP_CONFIG" > ~/.pip/pip.conf
...
...
RUN pip install -r requirements.txt
And then, I can do what I want, write a pip config to image from gitlab ci variable.
Hope can help others.
I have a script used in the preapration of a Docker image. I have this in the Dockerfile:
COPY my_script /
RUN bash -c "/my_script"
The my_script file contains secrets that I don't want in the image (it deletes itself when it finishes).
The problem is that the file remains in the image despite being deleted because the COPY is a separate layer. What I need is for both COPY and RUN to affect the same layer.
How can I COPY and RUN a script so that both actions affect the same layer?
take a look to multi-stage:
Use multi-stage builds
With multi-stage builds, you use multiple FROM statements in your
Dockerfile. Each FROM instruction can use a different base, and each
of them begins a new stage of the build. You can selectively copy
artifacts from one stage to another, leaving behind everything you
don’t want in the final image. To show how this works, let’s adapt the
Dockerfile from the previous section to use multi-stage builds.
Dockerfile:
FROM golang:1.7.3
WORKDIR /go/src/github.com/alexellis/href-counter/
RUN go get -d -v golang.org/x/net/html
COPY app.go .
RUN CGO_ENABLED=0 GOOS=linux go build -a -installsuffix cgo -o app .
FROM alpine:latest
RUN apk --no-cache add ca-certificates
WORKDIR /root/
COPY --from=0 /go/src/github.com/alexellis/href-counter/app .
CMD ["./app"]
As of 18.09 you can use docker build --secret to use secret information during the build process. The secrets are mounted into the build environment and aren't stored in the final image.
RUN --mount=type=secret,id=script,dst=/my_script \
bash -c /my_script
$ docker build --secret id=script,src=my_script.sh
The script wouldn't need to delete itself.
This can be handled by BuildKit:
# syntax=docker/dockerfile:experimental
FROM ...
RUN --mount=type=bind,target=/my_script,source=my_script,rw \
bash -c "/my_script"
You would then build with:
DOCKER_BUILDKIT=1 docker build -t my_image .
This also sounds like you are trying to inject secrets into the build, e.g. to pull from a private git repo. BuildKit also allows you to specify:
# syntax=docker/dockerfile:experimental
FROM ...
RUN --mount=type=secret,target=/creds,id=cred \
bash -c "/my_script -i /creds"
You would then build with:
DOCKER_BUILDKIT=1 docker build -t my_image --secret id=creds,src=./creds .
With both of the BuildKit options, the mount command never actually adds the file to your image. It only makes the file available as a bind mount during that single RUN step. As long as that RUN step does not output the secret to another file in your image, the secret is never injected in the image.
For more on the BuildKit experimental syntax, see: https://github.com/moby/buildkit/blob/master/frontend/dockerfile/docs/experimental.md
I guess you can use a workaround to do this:
Put my_script in a local http server which for example using python -m SimpleHTTPServer, and then the file could be accessed with http://http_server_ip:8000/my_script
Then, in Dockerfile use next:
RUN curl http://http_server_ip:8000/my_script > /my_script && chmod +x /my_script && bash -c "/my_script"
This workaround assure file add & delete in same layer, of course, you may need to add curl install in Dockerfile.
I think RUN --mount=type=bind,source=my_script,target=/my_script bash /my_script in BuildKit can solve your problem.
First, prepare BuildKit
export DOCKER_CLI_EXPERIMENTAL=enabled
export DOCKER_BUILDKIT=1
docker buildx create --name mybuilder --driver docker-container
docker buildx use mybuilder
Then, write your Dockerfile.
# syntax = docker/dockerfile:experimental
FORM debian
## something
RUN --mount=type=bind,source=my_script,target=/my_script bash -c /my_script
The first lint must be # syntax = docker/dockerfile:experimental because it's experimental feature.
And this method are not work in Play with docker, but work on my computer...
My computer us Ubuntu 20.04 with docker 19.03.12
Then, build it with
docker buildx build --platform linux/amd64 -t user/imgname -f ./Dockerfile . --push
I use Docker Toolbox for windows (for compatibility issues) and in the Dockerfile I specify an ARG so that I can use it when building the image with --build-arg command. Inside the dockerfile I also have some COPY commands and there I would like to use my variable but when I run docker build --build-arg VERSION_APP=something . it does not translate the variable . I have already used $VERSION_APP or ${VERSION_APP} or %VERSION_APP%.
FROM alpine
MAINTAINER Marinos
ARG VERSION_APP
RUN apk update && apk add dos2unix
COPY script.sh /home/script.sh
RUN chmod a+x /home/script.sh
RUN dos2unix /home/script.sh
RUN sh /home/script.sh
COPY installation.txt /home/Desktop/${VERSION_APP}
UPDATE
It seems that you should pass the whole path to the variable you use that is how I got it working.
If you actually use the command below then it is expected not to work because the argument called VERSION_APP
docker build --build-arg myVar=something
So the command should be
docker build --build-arg VERSION_APP=something
And in Dockerfile it should be %VERSION_APP% also you may need to use ENV like below:
ARG VERSION_APP
ENV VERSION_APP ${VERSION_APP}
I use docker for development and in production for laravel project. I have slightly different dockerfile for development and production. For example I am mounting local directory to docker container in development environment so that I don't need to do docker build for every change in code.
As mounted directory will only be available when running the docker container I can't put commands like "composer install" or "npm install" in dockerfile for development.
Currently I am managing two docker files, is there any way that I can do this with single docker file and decide which commands to run when doing docker build by sending parameters.
What I am trying to achieve is
In docker file
...
IF PROD THEN RUN composer install
...
During docker build
docker build [PROD] -t mytag .
As a best practice you should try to aim to use one Dockerfile to avoid unexpected errors between different environments. However, you may have a usecase where you cannot do that.
The Dockerfile syntax is not rich enough to support such a scenario, however you can use shell scripts to achieve that.
Create a shell script, called install.sh that does something like:
if [ ${ENV} = "DEV" ]; then
composer install
else
npm install
fi
In your Dockerfile add this script and then execute it when building
...
COPY install.sh install.sh
RUN chmod u+x install.sh && ./install.sh
...
When building pass a build arg to specify the environment, example:
docker build --build-arg "ENV=PROD" ...
UPDATE (2020):
Since this was written 3 years ago, many things have changed (including my opinion about this topic). My suggested way of doing this, is using one dockerfile and using scripts. Please see #yamenk's answer.
ORIGINAL:
You can use two different Dockerfiles.
# ./Dockerfile (non production)
FROM foo/bar
MAINTAINER ...
# ....
And a second one:
# ./Dockerfile.production
FROM foo/bar
MAINTAINER ...
RUN composer install
While calling the build command, you can tell which file it should use:
$> docker build -t mytag .
$> docker build -t mytag-production -f Dockerfile.production .
You can use build args directly without providing additional sh script. Might look a little messy, though. But it works.
Dockerfile must be like this:
FROM alpine
ARG mode
RUN if [ "x$mode" = "xdev" ] ; then echo "Development" ; else echo "Production" ; fi
And commands to check are:
docker build -t app --build-arg mode=dev .
docker build -t app --build-arg mode=prod .
I have tried several approaches to this, including using docker-compose, a multi-stage build, passing an argument through a file and the approaches used in other answers. My company needed a good way to do this and after trying these, here is my opinion.
The best method is to pass the arg through the cmd. You can pass it through vscode while right clicking and choosing build image
Image of visual studio code while clicking image build
using this code:
ARG BuildMode
RUN echo $BuildMode
RUN if [ "$BuildMode" = "debug" ] ; then apt-get update \
&& apt-get install -y --no-install-recommends \
unzip \
&& rm -rf /var/lib/apt/lists/* \
&& curl -sSL https://aka.ms/getvsdbgsh | bash /dev/stdin -v latest -l /vsdbg ; fi
and in the build section of dockerfile:
ARG BuildMode
ENV Environment=${BuildMode:-debug}
RUN dotnet build "debugging.csproj" -c $Environment -o /app
FROM build AS publish
RUN dotnet publish "debugging.csproj" -c $Environment -o /app
The best way to do it is with .env file in your project.
You can define two variables CONTEXTDIRECTORY and DOCKERFILENAME
And create Dockerfile-dev and Dockerfile-prod
This is example of using it:
docker compose file:
services:
serviceA:
build:
context: ${CONTEXTDIRECTORY:-./prod_context}
dockerfile: ${DOCKERFILENAME:-./nginx/Dockerfile-prod}
.env file in the root of project:
CONTEXTDIRECTORY=./
DOCKERFILENAME=Dockerfile-dev
Be careful with the context. Its path starts from the directory with the dockerfile that you specified, not from docker-compose directory.
In default values i using prod, because if you forget to specify env variables, you won't be able to accidentally build a dev version in production
Solution with diffrent dockerfiles is more convinient, then scripts. It's easier to change and maintain
I am using RUN instruction within a Dockerfile to install a rpm
RUN yum -y install samplerpm-2.3
However, I want to pass the value "2.3" as an argument.
My RUN instruction should look something like:
RUN yum -y install samplerpm-$arg
where $arg=2.3
As of Docker 1.9, You are looking for --build-arg and the ARG instruction.
Check out this document for reference. This will allow you to add ARG arg to the Dockerfile and then build with
docker build --build-arg arg=2.3 .