Why does the script run as a node application when starting the sh docker container?

Question

bash

Hello everyone)

There is the following Dockerfile:

FROM node:16-alpine

ENV PORT=5014
ENV NODE_ENV=development
ENV DATABASE_PORT=3306

WORKDIR /usr/src/app

RUN apk update && apk add bash tini tzdata
RUN cp /usr/share/zoneinfo/Europe/Moscow /etc/localtime \
    && echo "Europe/Moscow" > /etc/timezone

RUN wget https://raw.githubusercontent.com/vishnubob/wait-for-it/master/wait-for-it.sh
RUN chmod a+x wait-for-it.sh

COPY package*.json ./
COPY ["src", "./src"]
COPY ["test", "./test"]
RUN npm ci
RUN chmod a+x src/start.sh

EXPOSE 8080

CMD ["src/start.sh"]

Accordingly, at the start of the container, src/start.sh is launched with the following content:

#!/bin/bash

set -e

./wait-for-it.sh "food_calc_mysql:${DATABASE_PORT}" --timeout=1 -- echo "Database is up"

if ; then
  exec npx nodemon --exec "node ./src/bin/www"
else
  echo "NODE_ENV is not set"
  exit 1
fi

and this error occurs:

/usr/src/app/src/start.sh:5
./wait-for-it.sh "food_calc_mysql:${DATABASE_PORT}" --timeout=1 -- echo "Database is up"
 ^

SyntaxError: Unexpected token '/'
    at Object.compileFunction (node:vm:352:18)
    at wrapSafe (node:internal/modules/cjs/loader:1031:15)
    at Module._compile (node:internal/modules/cjs/loader:1065:27)
    at Object.Module._extensions..js (node:internal/modules/cjs/loader:1153:10)
    at Module.load (node:internal/modules/cjs/loader:981:32)
    at Function.Module._load (node:internal/modules/cjs/loader:822:12)
    at Function.executeUserEntryPoint [as runMain] (node:internal/modules/run_main:81:12)
    at node:internal/main/run_main_module:17:47

i.e. the src/start.sh script runs as a node.js application, not as a bash script. I don't understand why this is happening.

Thank you.

Answer 1

In the base image, the ENTRYPOINT is set to this script .
In particular, it says that if the command does not look like an executable, then it is assumed that this is JS that needs to be executed by the node.
In your case, probably the easiest is to set the full path to the file in CMD
CMD ["/usr/src/app/src/start.sh"]

Answer 2

Most likely the base image you're using has an ENTRYPOINT set up that turns your src/start.sh into node src/start.sh or something.
See what exactly is written in ENTRYPOIN and adjust or replace it.