I'm trying to create a Dockerfile to then build a Maven project.
I wonder how to fix the Dockerfile and what command to then execute.
I would like to know how to run the build so that it does NOT download all the Maven dependencies every time it builds when the source code, sitting in the src/ directory, has NOT changed.
Here is my Dockerfile file:
FROM maven:3.3.9-jdk-8
RUN mkdir -p /usr/src/app
WORKDIR /usr/src/app
RUN cd /usr/src/app
ADD pom.xml /usr/src/app
RUN mvn dependency:resolve
ADD src /usr/src/app
RUN mvn package
ENTRYPOINT ["mvn"]
CMD ["package"]
Should I run the docker run --rm -it toolbox command or the docker build -t toolbox . command ?
Both of these above commands run fine, except that they both download all the Maven dependencies even if the source code has not been touched.
That's how Docker works. Every time you do docker run, it creates a new container which does not have any access to the files in the old container. So, it download all dependencies it requires. You can circumvent this by declaring an external volume. Looking at the Dockerfile of Maven, it declares a volume /root/.m2. So, you can use a directory in your host machine and attach it to this volume by -v option. Your Docker command would be,
`docker run -v <directory-in-your-host>:/root/.m2 <other-options-and-commands>
Every time you run a new docker run, Maven will look into your local directory before downloading the dependency.
However, my question is why don't you build your app first and use the resulting jar to create the docker images unless you have any specific reasons. You can create your own Dockerfile using java base image or simply use one of the docker-maven-plugin like spotify available out there. That makes your life a lot easier.
Related
I need to run Maven build inside container and afterwards I need to run make command.
For executing Maven, I did the following inside dockerfile
FROM maven:3.8.1-adoptopenjdk-11 AS build
COPY src /usr/src/app/src
COPY pom.xml /usr/src/app
RUN mvn -f /usr/src/app/pom.xml clean package
After maven execution, some jar files are generated, which is needed to run make command (used in make file)
Now my question is how to get docker image for make, and how do I use it in same dockerfile? I tried to find docker image for make but didn't get it directly in dockerhub.
I'm familiar with building java code but not with building C/C++ code with make. Any help would be appreciated.
I'm reading about dockerization of Spring Boot applications and all (or almost all) tutorials are based on some simple Dockerfile like
FROM openjdk:8-jdk-alpine
ARG JAR_FILE=target/*.jar
COPY ${JAR_FILE} app.jar
ENTRYPOINT ["java","-jar","/app.jar"]
It usually work (however you may need to change some build target paths) but as far as I understand it requires us to build the application jar before the docker build command will be run.
I'm actually working with Gradle but for the Maven, I guess, it looks the same.
My question is: is it good convention?
If I'll download some repostitory and run docker build, regardless having proper Dockerfile, it will fail because there is no target/*.jar file (at least if someone did not commit the /build directory :P).
Should we then include some ./gradlew build commands in the Dockerfile?
https://github.com/palantir/gradle-docker
you should use this project
or
jar_path=$(find . |grep $APP_NAME|grep jar|grep -v original|grep -v repository|grep -v templates)
mv $jar_path ./app.jar
I'm building a maven project inside a docker container:
docker run build-image "mvn clean package -f ./pom.xml"
The source and workdir in the Dockerfile for "build-image" are located at /src/ (having two subfolders with each containing one submodule with pom.xml, parent pom at /src/pom.xml)
When the build is finished, the container exits. Then, I want to extract the build artifacts:
docker cp <container-id>:/src/module1/target/*.war ./
I get an error:
Error response from daemon: Could not find the file /src/<module1>/target/*.war in container silly_nobel
When I specify the file without using the wildcard:
docker cp <container-id>:/src/<module1>/target/<module1>##0.1.0-SNAPSHOT.war ./
it succeeds..
Is this intended behaviour or a bug? I googled a bit but could not find a similar post with that problem. docker version is 18.02.0-ce, build fc4de44
Best regards
docker cp does not support wildcards at the moment (github discussion)
But you can get what you want by using multi stage builds. In multi stage builds you can use COPY which allows wildcards.
This is a short example:
FROM alpine as builder
RUN touch foo.txt
RUN touch bar.txt
FROM alpine
COPY --from=builder /*.txt ./
Build an run image:
$ docker build -t foobar .
$ docker run foobar ls
bar.txt
bin
dev
etc
foo.txt
...
I am trying to perform "mvn install" to create war file from Dockerfile. Bellow is the Dockerfile
FROM scratch
FROM ubuntu:16.04
RUN mkdir /opt/java8
RUN mkdir /opt/tomcat8
RUN mkdir /opt/maven3
ENV JAVA_HOME /opt/java8
ENV CATALINA_HOME /opt/tomcat8
ENV PATH $PATH:$JAVA_HOME/bin:$CATALINA_HOME/bin:$M2_HOME/bin
ADD jdk1.8.0_112 /opt/java8
ADD apache-tomcat-8.0.38 /opt/tomcat8
WORKDIR /home/veni/git/M_UserTP
RUN mvn install
WORKDIR /home/veni/git/M_UserTP/target
RUN mv M_UserTP.war
/home/veni/Documents/dhaval_bhoot/docker_images/tomcat1
ADD M_UserTP.war /opt/tomcat8/webapps
EXPOSE 8080
CMD ["catalina.sh", "run"]
I also added the path of bin directory of maven in PATH environment variable.
PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games:/home/veni/Documents/apache-maven-3.3.9/bin/
This path I set from root user in my machine, I also added same path in PATH variable as normal user already.
So now I exit from root user and come back by sudo su to be root user and check PATH variable, it has not path of maven
So when I make docker build of image I get the bellow error
/bin/sh: 1: mvn: not found
The command '/bin/sh -c mvn install' returned a non-zero code: 127
Given that you want to run your application in a Tomcat 8 Docker container:
Your maven project should be laid out like:
M_UserTP
+ Dockerfile
+ pom.xml
+ src
+ target
This is a standard maven layout plus your Dockerfile.
Ensure that your pom.xml contains the following finalName defined in it:
<build>
<finalName>${project.artifactId}</finalName>
...
</build>
Your Dockerfile can be really simple:
FROM tomcat:8.0
COPY target/M_UserTP.war $CATALINA_HOME/webapps/
(Note how the finalName is used by the Dockerfile)
To build it, execute:
mvn clean install && docker build . -t Bhoot/M_UserTP
You can use what ever -t tag that you want.
It will take some time the first time that you do this while the standard Tomcat 8 image is downloaded.
Now you can run it:
docker run --detach --publish 8080:8080 Bhoot/M_UserTP
You don't really want to build your WAR file in the docker image. This will suck all the maven repository components used by maven to build your application into the image. This space is not recoverable as images will only ever grow - they never shrink again.
Have you considered using a maven:onbuild image in conjunction with a multi-stage build for this?
An example of such a usage (with a Spring Boot application) is available here: https://github.com/anokun7/docker-springframework/blob/master/Dockerfile
Your container have its own filesystem.
So the mvn binary available on your system, is not available on a base ubuntu image.
You should install it first in your container (with a RUN apt-get install..)
You will then be able to use it in the next RUN
Try getting inside your container (after commenting out maven layer and everything below) and type which mvn. This will display the absolute path of the maven binary. Then use that absolute path inside your Dockerfile instead of just mvn.
Example:
mvn -> /opt/maven/bin/mvn
I have a following Dockerfile in my pet project:
FROM java:8
ADD target/sources-registry-0.0.1-SNAPSHOT.jar sources-registry.jar
RUN bash -c 'touch /sources-registry.jar'
ENTRYPOINT ["java","-Djava.security.egd=file:/dev/./urandom","-jar","/sources-registry.jar"]
EXPOSE 8761
And everything perfectly works - image is created and can be run. Now a bit of description about the project: it is a maven based project and before actually executing the Dockerfile I have to manually run mvn package.
However, if I change the Dokerfile to (because I do not want manually to run mvn package and want to automate it)
FROM java:8
RUN ls target
RUN ./mvnw package
ADD target/sources-registry-0.0.1-SNAPSHOT.jar sources-registry.jar
RUN bash -c 'touch /sources-registry.jar'
#ENTRYPOINT ["java","-Djava.security.egd=file:/dev/./urandom","-jar","/sources-registry.jar"]
EXPOSE 8761
then while execution I get /bin/sh: 1: ./mvnw: not found. However, mvnw is in my project files near the pom.xml.
Even more if I just do following Dockerfile
FROM java:8
RUN ls target/
then I get ls: cannot access target/: No such file or directory.
Can someone please explain this behaviour?
I mean why I can actually do something with target folder (first
Dockerfile) even if does not exist (third Dockerfile)?
How project files (and what files) get copied into a created
container?
The main question: Why second Dockerfile is not working? And how I can make it work?
The ADD command copies over the sources-registry.jar file into the Docker image, so that the first example is able to execute it. If you want to use any other files inside the container, you need to include them in the image as well (using ADD or COPY). See the reference docs for more information