nodemon start errors on Heroku

I've been running into the same start error when I deploy onto Heroku. I know it has something to do with my start script but I can't seem to pin down the issue.

I'm running into this error on app start:

2018-10-22T15:31:04.927032+00:00 heroku[web.1]: Process exited with status 1
2018-10-22T15:31:04.944756+00:00 heroku[web.1]: State changed from starting to crashed
2018-10-22T15:31:04.946982+00:00 heroku[web.1]: State changed from crashed to starting
2018-10-22T15:31:04.804183+00:00 app[web.1]:
2018-10-22T15:31:04.804198+00:00 app[web.1]: > Backend@ start /app
2018-10-22T15:31:04.804200+00:00 app[web.1]: > nodemon -e js,graphql -x node -r dotenv/config src/index.js
2018-10-22T15:31:04.804202+00:00 app[web.1]:
2018-10-22T15:31:04.810881+00:00 app[web.1]: sh: 1: nodemon: not found
2018-10-22T15:31:04.817652+00:00 app[web.1]: npm ERR! file sh
2018-10-22T15:31:04.818091+00:00 app[web.1]: npm ERR! code ELIFECYCLE
2018-10-22T15:31:04.818534+00:00 app[web.1]: npm ERR! errno ENOENT
2018-10-22T15:31:04.818822+00:00 app[web.1]: npm ERR! syscall spawn
2018-10-22T15:31:04.820778+00:00 app[web.1]: npm ERR! Backend@ start: `nodemon -e js,graphql -x node -r dotenv/config src/index.js`
2018-10-22T15:31:04.821033+00:00 app[web.1]: npm ERR! spawn ENOENT
2018-10-22T15:31:04.821320+00:00 app[web.1]: npm ERR!
2018-10-22T15:31:04.821464+00:00 app[web.1]: npm ERR! Failed at the Backend@ start script.
2018-10-22T15:31:04.821628+00:00 app[web.1]: npm ERR! This is probably not a problem with npm. There is likely additional logging output above.
2018-10-22T15:31:04.829156+00:00 app[web.1]:
2018-10-22T15:31:04.829411+00:00 app[web.1]: npm ERR! A complete log of this run can be found in:
2018-10-22T15:31:04.829659+00:00 app[web.1]: npm ERR!     /app/.npm/_logs/2018-10-22T15_31_04_823Z-debug.log
2018-10-22T15:31:09.008630+00:00 heroku[web.1]: Starting process with command `npm start`
2018-10-22T15:31:12.142111+00:00 app[web.1]:
2018-10-22T15:31:12.142136+00:00 app[web.1]: > Backend@ start /app
2018-10-22T15:31:12.142138+00:00 app[web.1]: > nodemon -e js,graphql -x node -r dotenv/config src/index.js
2018-10-22T15:31:12.142140+00:00 app[web.1]:
2018-10-22T15:31:12.151638+00:00 app[web.1]: sh: 1: nodemon: not found
2018-10-22T15:31:12.157445+00:00 app[web.1]: npm ERR! file sh
2018-10-22T15:31:12.157635+00:00 app[web.1]: npm ERR! code ELIFECYCLE
2018-10-22T15:31:12.157787+00:00 app[web.1]: npm ERR! errno ENOENT
2018-10-22T15:31:12.157931+00:00 app[web.1]: npm ERR! syscall spawn
2018-10-22T15:31:12.159057+00:00 app[web.1]: npm ERR! Backend@ start: `nodemon -e js,graphql -x node -r dotenv/config src/index.js`
2018-10-22T15:31:12.159155+00:00 app[web.1]: npm ERR! spawn ENOENT
2018-10-22T15:31:12.159323+00:00 app[web.1]: npm ERR!
2018-10-22T15:31:12.159423+00:00 app[web.1]: npm ERR! Failed at the Backend@ start script.
2018-10-22T15:31:12.159520+00:00 app[web.1]: npm ERR! This is probably not a problem with npm. There is likely additional logging output above.
2018-10-22T15:31:12.164017+00:00 app[web.1]:

So it can't find nodemon, despite it being installed. Here's my package.json:

{
  "name": "Backend",
  "scripts": {
    "start": "nodemon -e js,graphql -x node -r dotenv/config src/index.js",
    "debug": "nodemon -e js,graphql -x node --inspect -r dotenv/config src/index.js",
    "playground": "graphql playground",
    "dev": "npm-run-all --parallel start playground"
  },
  "dependencies": {
    "bcryptjs": "2.4.3",
    "googleapis": "^27.0.0",
    "graphql-yoga": "1.12.0",
    "jsonwebtoken": "8.2.1",
    "multer": "^1.4.0",
    "node-schedule": "^1.3.0",
    "nodemailer": "^4.6.4",
    "prisma-binding": "1.5.17",
    "winston": "^2.4.2",
    "nodemon": "1.17.3"
  },
  "devDependencies": {
    "dotenv": "5.0.1",
    "graphql-cli": "2.15.9",
    "nodemon": "1.17.3",
    "npm-run-all": "4.1.2",
    "prisma": "^1.6.3"
  }
}

and my procfile is web: node src/index.js

Any help would be much appreciated, thanks.

Solution

It looks like nodemon -e js,graphql -x node -r dotenv/config src/index.js is being called by something other than npm, which is causing the issue with nodemon being missing, regardless of whether or not nodemon is actually present.

Here are some things you can do to isolate the root cause of the issue:

Confirm that the app works locally, with and without nodemon.
Ensure that your Procfile starts with a capitalized P (https://devcenter.heroku.com/articles/procfile#procfile-format)
Update the web directive in your profile to npm start

If the above changes don't work, run through the following:

Navigate to the root directory of your project, and start a remote session as follows: heroku ps:exec.
Once inside your app's dyno, run npm ls. If this fails, your dependencies haven't been installed properly (which looks like a Heroku issue)
If the above command succeeds, run npm start to confirm that the app can launch.