Currently we have 9 tools running tomcat webservices. In the long term we'd like to not be responsible for maintaining tomcat - need to find an alternative that works for all these tools. Ideally they'd use an embedded HTTP server like Jetty (for new users) and for older ones we find a equivalent that can work.
In my case, my Java tool replacer is prepared to be packaged as a WAR to be run in Tomcat, or as an SpringBoot standalone JAR.
I have been running the tool as a WAR so far. On the other side, when running the tool as a JAR in the lab server, I am not able to access it from the outside (https://tools.wmflabs.org/replacer/), I guess because of the port used.
Any hint about the port to use so the tool can be accessed in a regular browser ?
For a job grid webservice, a PORT environment variable will be exported by the webservice-runner process that is spawned to start your webservice.
For a Kubernetes webservice, the expected port is always 8000.
I have tried the port 8000 with no success.
I have started the Kubernetes JDK8 shell:
webservice --backend=kubernetes jdk8 shell
Then I have started the standalone JAR with an embedded Tomcat server:
java -jar replacer.jar
In the log displayed, I can read the following message:
Tomcat started on port(s): 8000 (http)
But when I try to access the tool as usual in https://tools.wmflabs.org/replacer/ :
The URI you have requested, /replacer/, is not currently serviced.
The shell action does not set the attributes on the Kubernetes pod which are required for our ingress solution to connect the frontend proxy to the pod. It took a bit of digging for me to figure out how the jdk8 backend is expected to work. Eventually I determined that it is setup to use our "generic" startup mechanism.
This process should work to start your tool as a Kubernetes webservice:
- Create a wrapper script that will start your java process. I'm going to put this example at $HOME/replace.sh in the test environment I'm using:
#!/bin/sh cd $HOME exec java -jar $HOME/replacer.jar
- Tell webservice to run this script inside a jdk8 container:
$ webservice --backend=kubernetes jdk8 start $HOME/replacer.sh
It would be a bit nicer if you could give the whole java -jar replacer.jar command directly to webservice, but the options parsing the webservice script is doing right now has problems with any "extra" args that start with '-'.
The proposed solution has worked for me, so I will stop working with Tomcat. This will allow me also to finally migrate to Java 8.
For the record, besides changing the port, I have had to also change the context path in the Spring Boot configuration file:
server: port: 8000 servlet.context-path: /replacer/
Thanks a lot!