If you're experiencing a build issue during the deployment of your application, using Docker on your local machine, you can debug the issue further.

On your local machine:

1. Ensure you've installed Docker.

2. Go to the root of your application project and run:

docker run -it -v $(pwd):/tmp/app gliderlabs/herokuish bash

3. You will now be running inside a Docker container that uses the Herokuish library, which is internally used by Dokku.

4. To see a list of current buildpacks, do:

herokuish buildpack list

5. To install an external buildpack, do:

herokuish buildpack install https://url-to-buildpack.git

6. Now test the build process by running:

herokuish test

If you encounter any errors and can't figure out next steps, please contact us. Some buildpacks might require the presence of environment variables to be set. Some of these can be set to arbitrary values in order to test your build. For example, the Meteor buildpack requires MONGO_URL and ROOT_URL:

export MONGO_URL=mongodb://user:password@
export ROOT_URL=http://localhost

Note: in the above example, MongoDB was started with the following command:

docker run -d -p 27017:27017 -e SSL_ON="" -e MONGODB_USER="user" -e MONGODB_PASS="password" --name mongodb healthcareblocks/mongodb

And then docker inspect mongodb was run to identify the IP address.