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Deployment Tasks

New as of 0.5.0

Sometimes you need to run a command on at deployment time, but before an app is completely deployed. Common use cases include:

  • Checking a database is initialised
  • Running database migrations
  • Any commands required to set up the server (e.g. something like a Django collectstatic)

app.json and scripts.dokku

Dokku accomplishes this by using an app.json file. The format in use is similar to format of Heroku's app.json. However, dokku currently only supports the nodes scripts.dokku.predeploy and scripts.dokku.postdeploy. For buildpack apps, simply place an app.json file in the root of your repository. For dockerfile apps, place app.json in the configured WORKDIR directory; otherwise dokku defaults to the buildpack app behavior of looking in /app.

NOTE: postdeploy changes are NOT committed to the app image.

Example app.json

{
  "name": "barebones nodejs",
  "description": "A barebones Node.js app using Express 4.",
  "keywords": [
    "nodejs",
    "express"
  ],
  "repository": "https://github.com/michaelshobbs/node-js-sample",
  "scripts": {
    "dokku": {
      "predeploy": "touch /app/predeploy.test",
      "postdeploy": "curl https://some.external.api.service.com/deployment?state=success"
    }
  },
  "env": {
    "SECRET_TOKEN": {
      "description": "A secret key for verifying the integrity of signed cookies.",
      "value": "secret"
    },
    "WEB_CONCURRENCY": {
      "description": "The number of processes to run.",
      "generator": "echo 5"
    }
  },
  "image": "gliderlabs/herokuish",
  "addons": [
    "dokku-postgres",
    "dokku-redis"
  ],
  "buildpacks": [
    {
      "url": "https://github.com/heroku/heroku-buildpack-nodejs"
    }
  ]
}