How to set azure-function app port from docker -e variable?

Question

I'm trying to create azure queue listener in docker and deploy it as an azure function.

Azure runs my docker with command similar to following:

docker run -d -p 16506:8081 --name queue-listener_0 -e PORT=8081 ... 

The only thing that I need to do is to get that port variable and put it to func start --port $PORT field in entrypoint script, but the problem is that the bash doesn't see variables put through -e key.

Dockerfile:

FROM tarampampam/node:10.10-alpine as buildContainer


COPY package.json package-lock.json entrypoint.sh host.json extensions.csproj proxies.json /app/
COPY /QueueTrigger/function.json /app/
#COPY /app/dist /app/dist

### only for local launch
#COPY  /local.settings.json /app


WORKDIR /app

RUN npm install
COPY . /app
RUN npm run build

FROM mcr.microsoft.com/azure-functions/node:2.0
WORKDIR /app
ENV AzureWebJobsScriptRoot=/app
ENV AzureWebJobs_ExtensionsPath=/app/bin

# Copy dependency definitions
COPY --from=buildContainer /app/package.json /app/

# Get all the code needed to run the app
COPY --from=buildContainer /app/dist /app/
COPY --from=buildContainer /app/function.json /app/QueueTrigger/
COPY --from=buildContainer /app/bin /app/bin
COPY --from=buildContainer /app/entrypoint.sh /app
COPY --from=buildContainer /app/host.json /app
COPY --from=buildContainer /app/extensions.csproj /app
COPY --from=buildContainer /app/proxies.json /app
COPY --from=buildContainer /app/resources /app/resources

### only for local launch
#COPY --from=buildContainer /app/local.settings.json /app


RUN chmod 755 /app/entrypoint.sh
COPY --from=buildContainer /app/node_modules /app/node_modules
RUN npm i -g azure-functions-core-tools@core --unsafe-perm true
RUN apt-get update && apt-get install -y ghostscript && gs -v

# Serve the app
ENTRYPOINT ["sh", "entrypoint.sh"]

Entrypoint:

#!/bin/bash

func start --port $PORT

Answer 1

func is more for local development.

The mcr.microsoft.com/azure-functions/node:2.0 image already has the runtime packaged with the default entrypoint set to start it. You really don't need func here.

But, if ever required, even with just the runtime, you can customize the port

1. You would have to remove these last few lines from the container

RUN chmod 755 /app/entrypoint.sh
RUN npm i -g azure-functions-core-tools@core --unsafe-perm true

# Serve the app
ENTRYPOINT ["sh", "entrypoint.sh"]

2. And run your container like this

docker run -d -p 16506:8081 --name queue-listener_0 -e ASPNETCORE_URLS=http://+:8081 ... 

Note that local.settings.json won't be picked up by the runtime. Your App Settings would have to be set manually as environment variables.