Building Docker Images with heroku.yml (failed to bind to port)-CodePudding

my Dockerfile is

FROM node:16
WORKDIR /app
COPY package*.json ./

RUN npm install
copy . /app

# Expose 9000
CMD ["npm","start"]

heroku.yml

build:
  docker:
    web:
       Dockerfile

index.js contains (using express)

const PORT = process.env.PORT || 3002;
const HOST = "localhost";
app.listen(PORT,HOST, () => console.log(`listening on port ${PORT}`));

After git push heroku master the web process failing to bind after 1 minute of starting. How can i resolve this ?

listening on port 25941
Error R10 (Boot timeout) -> Web process failed to bind to $PORT within 60 seconds of launch
Stopping process with SIGKILL
Process exited with status 137
State changed from starting to crashed

CodePudding user response：

After doing some reading on Heroku, it seems it specifies a random port. It also says here that Dockerfile EXPOSE is not respected.

I'd guess the problem is with HOST:

const HOST = "localhost";
app.listen(PORT,HOST, () => console.log(`listening on port ${PORT}`));

The HOST parameter can be omitted and just the callback can be passed instead:

app.listen(PORT, () => console.log(`listening on port ${PORT}`));