Spring Boot Gradle app on Heroku: Unable to access jarfile

Question

I have a spring boot gradle app which I could run successfully on my PC by doing:

heroku local

It can also deploy on heroku successfully when I go:

git push heroku master

This is my result:

Counting objects: 17, done.
Delta compression using up to 4 threads.
Compressing objects: 100% (5/5), done.
Writing objects: 100% (9/9), 596 bytes | 0 bytes/s, done.
Total 9 (delta 3), reused 0 (delta 0)
remote: Compressing source files... done.
remote: Building source:
remote:
remote: -----> Fetching set buildpack https://github.com/heroku/heroku-buildpack-gradle... done

remote: -----> Gradle app detected
remote: -----> Installing OpenJDK 1.8... done
remote: -----> Building Gradle app...
remote:        WARNING: The Gradle buildpack is currently in Beta.
remote: -----> executing ./gradlew build
remote:        :compileJavaNote: Some input files use unchecked or unsafe operations.
remote:        Note: Recompile with -Xlint:unchecked for details.
remote:
remote:        :processResources
remote:        :classes
remote:        :jar
remote:        :bootRepackage
remote:        :assemble
remote:        :compileTestJava UP-TO-DATE
remote:        :processTestResources UP-TO-DATE
remote:        :testClasses UP-TO-DATE
remote:        :test UP-TO-DATE
remote:        :check UP-TO-DATE
remote:        :build
remote:
remote:        BUILD SUCCESSFUL
remote:
remote:        Total time: 11.935 secs
remote:
remote: -----> Discovering process types
remote:        Procfile declares types -> web
remote:
remote: -----> Compressing... done, 72.3MB
remote: -----> Launching... done, v9
remote:        https://myapp.herokuapp.com/ deployed to Heroku
remote:
remote: Verifying deploy... done.
To https://git.heroku.com/myapp.git
   6326429..291326d  master -> master

But when I try to access it on heroku, it crashes. The heroku logs says this:

2015-12-11T17:05:46.096985+00:00 heroku[api]: Deploy 291326d by [email protected]
2015-12-11T17:05:46.097021+00:00 heroku[api]: Release v9 created by [email protected]
2015-12-11T17:05:46.378258+00:00 heroku[slug-compiler]: Slug compilation started
2015-12-11T17:05:46.378269+00:00 heroku[slug-compiler]: Slug compilation finished
2015-12-11T17:05:46.755655+00:00 heroku[web.1]: State changed from crashed to starting
2015-12-11T17:05:53.121398+00:00 heroku[web.1]: Starting process with command `java -Dserver.port=5000 -jar  build/libs/myapp.jar`
2015-12-11T17:05:54.260741+00:00 app[web.1]: Error: Unable to access jarfile build/libs/myapp.jar
2015-12-11T17:05:54.784064+00:00 heroku[web.1]: State changed from starting to crashed
2015-12-11T17:05:54.773714+00:00 heroku[web.1]: Process exited with status 1
2015-12-11T17:05:54.788248+00:00 heroku[web.1]: State changed from crashed to starting

Why is it Unable to access jarfile build/libs/myapp.jar ?

When I navigate to that folder on my local PC, the jarfile is there.

I'm running out of ideas on how to solve this.

Answer 1

I eventually found a very helpful thread here: Running Spring app built with gradle on Heroku

Which helped me with my problem - this thread seems to be more detail than Heroku's official guide.

You must add the following code to your build.gradle file:

task stage(type: Copy, dependsOn: [clean, build]) {
    from jar.archivePath
    into project.rootDir
    rename {
        'app.jar'
    }
}
stage.mustRunAfter(clean)

clean << {
    project.file('app.jar').delete()
}

Then, point your Procfile to the app.jar:

web: java $JAVA_OPTS -jar app.jar