How can I deploy a java web app to heroku?

Question

I have a Java web app with Tomcat embedded in my jar file. I can containerize the app with Docker and run it with command java -jar -myapp.jar, but I can't run that container in Heroku. I tried using heroku CLI to dockerize and deploy, but Heroku gives me an error of "can't access jarfile".

I tried to fix this by using heroku deploy:jar to deploy my fat jar, but this erroneously gives me an error:

 heroku deploy:jar target/*.jar -a medscanner2
-----> Packaging application...
   - app: medscanner2
   - including: target/medscanner2.jar
   ! ERROR: Could not get API key! Please install the Heroku CLI and run 
   `heroku login` or set the HEROKU_API_KEY environment variable.
   ! Re-run with HEROKU_DEBUG=1 for more info.
   !There was a problem deploying to medscanner2.
   !Make sure you have permission to deploy by running: heroku apps:info -a 
    medscanner2

I am signed into Heroku and I can use heroku auth:whoami to verify that, I can push containers and deploy them, so this error doesn't make any sense. I reran with HEROKU_DEBUG=1 and it did not return any more info.

I further tried to set the HEROKU_API_KEY variable in the CLI with a token I got from Heroku and this still caused the same error when I try to deploy the jar.

I am using a Procfile (although I am not sure it is necessary):

web: java -Dserver.port=$PORT -jar target/medscanner2.jar

Since the issue seems to be indicating there is an issue with access I don't see how the Procfile could be influencing it.

What is the best way for me to deploy a Java web app that does not using Spring Boot to Heroku? I have separately deployed the docker container successfully to Google app engine, so all this work for Heroku is very frustrating.

jvin · Accepted Answer · 2019-03-02 22:45:08Z

2

I ended up fixing this by using webapp-runner to deploy my app. It runs the webapp-runner jar which can run your .war files. This required adding the heroku-maven-plugin and maven-dependency-plugin.

I could then add a Procfile: web: java -jar target/dependency/webapp-runner.jar target/*.war --port $PORT

and use the Heroku CLI to add the app using git. The link with webapp-runner is a guide to deploying tomcat java apps with webapp-runner.

answered Mar 2, 2019 at 22:45

jvin

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