This simple project is just a showcase on how could the entire build process (not only spawning containers for test purposes) for a project can be performed in a dockerized environment.
There are though some struggles with docker which I've faced
while making this proof of concept, reason why I thought it would
be beneficial to share my findings with other software engineer
who may be trying to do something similar in their projects.
The underlying technologies showcased in this project are:
By running
mvn clean install
it can be seen that during the maven test phase a
a postgres container (through the usage of testcontainers library)
is being spawned.
[INFO] -------------------------------------------------------
[INFO] T E S T S
[INFO] -------------------------------------------------------
[INFO] Running eu.docker.postgres.PostgresContainerTest
SLF4J: Failed to load class "org.slf4j.impl.StaticLoggerBinder".
SLF4J: Defaulting to no-operation (NOP) logger implementation
SLF4J: See http://www.slf4j.org/codes.html#StaticLoggerBinder for further details.
ℹ︎ Checking the system...
✔ Docker version should be at least 1.6.0
✔ Docker environment should have more than 2GB free disk space
[INFO] Tests run: 1, Failures: 0, Errors: 0, Skipped: 0, Time elapsed: 6.5 s - in eu.docker.postgres.PostgresContainerTest
The above mentioned test spawns two containers:
➜ ~ docker ps
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
44786704c442 postgres:9.6.8 "docker-entrypoint.s…" 2 seconds ago Up 1 second 0.0.0.0:32799->5432/tcp boring_lamarr
644c74ed0cec quay.io/testcontainers/ryuk:0.2.2 "/app" 2 seconds ago Up 1 second 0.0.0.0:32798->8080/tcp testcontainers-ryuk-00894707-a42f-4ce3-a064-e9d8a6ceea0c
Probably a common question when looking at this project would be why bother with a dockerized build. A situation very fashionable lately is the transition to new Open JDK java version every version. Having a dockerized build allows a much less painful upgrade to the new java version.
The why question for the dockerized maven builds is answered in detail on the following website:
https://dzone.com/articles/maven-build-local-project-with-docker-why
TLDR; build an image with the dependencies for the project (java, maven, etc.)
Building the image is done by executing the following statement:
docker build -f docker/Dockerfile -t marius/dockerized-maven-jdk11 dockerHost=tcp://my.docker.host:2375 .
The dockerHost build argument referenced in the command above is located on another machine in my scenario (not the same machine as the one where the docker build is performed).
When building the image, I've struggled with enabling ryuk, so in a first phase I've disabled it through
ENV TESTCONTAINERS_RYUK_DISABLED="true"
By doing this, the building of the image succeeds.
➜ dockerized-maven-build git:(master) ✗ docker build -f docker/Dockerfile -t marius/dockerized-maven-jdk11 --build-arg dockerHost=tcp://my.docker.host:2375 .
....
[INFO] Tests run: 1, Failures: 0, Errors: 0, Skipped: 0, Time elapsed: 7.3 s - in eu.docker.postgres.PostgresContainerTest
[INFO]
[INFO] Results:
[INFO]
[INFO] Tests run: 1, Failures: 0, Errors: 0, Skipped: 0
[INFO]
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 10.703 s
[INFO] Finished at: 2019-02-26T06:26:48Z
[INFO] ------------------------------------------------------------------------
Removing intermediate container 862135fb53e6
---> 751ca9bfb34f
Successfully built 751ca9bfb34f
Successfully tagged marius/dockerized-maven-jdk11:latest
When using ryuk for test purposes, by commenting the Dockerfile line
#ENV TESTCONTAINERS_RYUK_DISABLED="true"
the build fails with the following exception:
...
2019-02-25 16:06:46 WARN ResourceReaper:137 - Can not connect to Ryuk at my.docker.host:32866
java.net.ConnectException: Connection refused (Connection refused)
at java.base/java.net.PlainSocketImpl.socketConnect(Native Method)
at java.base/java.net.AbstractPlainSocketImpl.doConnect(AbstractPlainSocketImpl.java:399)
at java.base/java.net.AbstractPlainSocketImpl.connectToAddress(AbstractPlainSocketImpl.java:242)
at java.base/java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:224)
at java.base/java.net.SocksSocketImpl.connect(SocksSocketImpl.java:403)
at java.base/java.net.Socket.connect(Socket.java:591)
at java.base/java.net.Socket.connect(Socket.java:540)
at java.base/java.net.Socket.<init>(Socket.java:436)
at java.base/java.net.Socket.<init>(Socket.java:213)
at org.testcontainers.utility.ResourceReaper.lambda$start$1(ResourceReaper.java:112)
at java.base/java.lang.Thread.run(Thread.java:834)
...
...
[ERROR] Errors:
[ERROR] PostgresContainerTest » ExceptionInInitializer
[INFO]
[ERROR] Tests run: 1, Failures: 0, Errors: 1, Skipped: 0
[INFO]
[INFO] ------------------------------------------------------------------------
[INFO] BUILD FAILURE
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 35.332 s
[INFO] Finished at: 2019-02-26T06:30:36Z
[INFO] ------------------------------------------------------------------------
[ERROR] Failed to execute goal org.apache.maven.plugins:maven-surefire-plugin:3.0.0-M3:test (default-test) on project dockerized-maven-build: There are test failures.
[ERROR]
[ERROR] Please refer to /project/target/surefire-reports for the individual test results.
[ERROR] Please refer to dump files (if any exist) [date].dump, [date]-jvmRun[N].dump and [date].dumpstream.
[ERROR] -> [Help 1]
[ERROR]
[ERROR] To see the full stack trace of the errors, re-run Maven with the -e switch.
[ERROR] Re-run Maven using the -X switch to enable full debug logging.
[ERROR]
[ERROR] For more information about the errors and possible solutions, please read the following articles:
[ERROR] [Help 1] http://cwiki.apache.org/confluence/display/MAVEN/MojoFailureException
The command '/bin/sh -c mvn clean test' returned a non-zero code: 1
This showcase is meant to share more light on the comments i've made here: