Docker compose up 'Exec format error' loading a library - node.js

Question

I'm developing a multi-module docker nodejs app with docker-compose. There's an issue with the natural node package needed by a module. It seems that it can't exec it. I tried to rebuild it on the fly with a RUN command, but nothing changed.
Here's the log when trying to run docker-compose up:
web_1 | /app/web-server/node_modules/natural/lib/natural/classifiers/classifier.js:32
web_1 | if (e.code !== 'MODULE_NOT_FOUND') throw e;
web_1 | ^
web_1 |
web_1 | Error: Error loading shared library /app/web-server/node_modules/webworker-threads/build/Release/WebWorkerThreads.node: Exec format error
web_1 | at Error (native)
web_1 | at Object.Module._extensions..node (module.js:597:18)
web_1 | at Module.load (module.js:487:32)
web_1 | at tryModuleLoad (module.js:446:12)
web_1 | at Function.Module._load (module.js:438:3)
web_1 | at Module.require (module.js:497:17)
web_1 | at require (internal/module.js:20:19)
web_1 | at bindings (/app/web-server/node_modules/bindings/bindings.js:81:44)
web_1 | at Object.<anonymous> (/app/web-server/node_modules/webworker-threads/index.js:1:105)
web_1 | at Module._compile (module.js:570:32)
web_1 | at Object.Module._extensions..js (module.js:579:10)
web_1 | at Module.load (module.js:487:32)
web_1 | at tryModuleLoad (module.js:446:12)
web_1 | at Function.Module._load (module.js:438:3)
web_1 | at Module.require (module.js:497:17)
web_1 | at require (internal/module.js:20:19)
Here's the package.json:
{
"name": "realaffinities",
"version": "1.0.0",
"description": "",
"main": "server/Server.js",
"keywords": [],
"author": "",
"license": "GPL-3.0",
"dependencies": {
"async": "^2.5.0",
"big-integer": "^1.6.23",
"body-parser": "1.9.0",
"express": "^4.15.3",
"express-validator": "^3.2.1",
"knex": "^0.13.0",
"mysql": "^2.14.1",
"natural": "^0.5.4",
"twit": "^2.2.9",
"url-exists": "^1.0.3",
"nodemon": "^1.11.0"
},
"devDependencies": {
"grunt": "^1.0.1",
"grunt-express-server": "^0.5.3",
"mocha": "^3.4.2",
"supertest": "^3.0.0",
"bcrypt": "1.0.2"
},
"scripts": {
"test": "mocha web-server/test",
"start": "node server/Server.js"
}
}
My dockerfile:
FROM node:6.11-alpine
EXPOSE 3000
ENV NODE_ENV development
RUN mkdir /app
WORKDIR /app
# add package.json and run npm install before adding the rest of the files
# this way, you only run npm install when package.json changes
ADD /web-server/package.json /app/package.json
RUN apk add --no-cache make gcc g++ python
RUN npm install -g mocha
RUN npm install
I don't know whether it's an issue of this particular node package or a knowledge lack of mine. If I run the same application locally on my mac without docker, it doesn't encounter this problem.

Answer 1

Someone reported same problem in this issue and his case was similar to yours. As discussed in comments, this worked for you, so I am posting this as answer also:
It sounds like it's trying to load a native extension that wasn't
compiled for linux (in the container) -- maybe you previously
installed the extension on OS X and it's trying to load that binary.
If you mean this is a node app, try just removing node_modules and run
npm install again
Fix that worked for you: rm -rf node_modules

Answer 2

Create a .dockerignore file and add /node_modules

Answer 3

None of the answers above worked for me. Switching from bcrypt to bcryptjs was what worked.

Answer 4

docker build --platform linux/amd64 .
Instead of the default arm64, this sometimes works.