Dockerfile COPY command fails intermittently - Cannot find pyproject.toml file during build

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1

I’m having weird issues with my Docker builds in a monorepo setup. Sometimes the build works fine, but other times it fails randomly with COPY errors for different services.

The error I keep getting looks like this:

=> ERROR [user-service builder 3/6] COPY requirements.txt package.json* ./                                                                                                                                                            0.0s
=> CANCELED [order-service internal] load build definition from Dockerfile                                                                                                                                                           0.1s
=> CANCELED [payment-service internal] load build definition from Dockerfile                                                                                                                                                          0.1s
=> ERROR [notification-service internal] load build context

This happens randomly - first build might work, second fails, then third works again. I have all the config files in the right place but Docker can’t seem to find them consistently.

Here’s my docker-compose service config:

notification-service:
    <<: *node-service
    build:
      context: .
      dockerfile: ./services/notification_app/Dockerfile
    ports: ["3001:3001"]
    depends_on: [redis, mongodb, rabbitmq]

And my Dockerfile:

FROM node:18-alpine AS deps

WORKDIR /app

RUN npm install -g yarn

COPY requirements.txt package.json ./

RUN yarn config set network-timeout 600000 && yarn install --frozen-lockfile --production=false

FROM node:18-alpine AS runner

WORKDIR /app

RUN addgroup -g 1001 -S nodegroup && adduser -S nodeuser -u 1001

COPY --from=deps /app/node_modules ./node_modules
COPY app/ .

RUN chown -R nodeuser:nodegroup /app
USER nodeuser
EXPOSE 3001
CMD ["node", "notification_app/server.js"]

Why does this keep happening? The files are definitely there in my project structure. Any ideas how to fix this inconsistent behavior?

2

I’ve encountered this issue with monorepos in the past. The problem stems from a mismatch between your build context and the file paths. While context: . points to your root directory, your Dockerfile is located in ./services/notification_app/, which can lead to Docker being confused about the file locations, especially given caching scenarios.

You can resolve this in two ways: either move the Dockerfile to the root and adjust the paths accordingly, or change the context to ./services/notification_app and update the copy commands in your Dockerfile. Additionally, I noticed you’re trying to copy requirements.txt into a Node.js container; ensure that this file is indeed present where Docker expects it to be. These intermittent errors likely indicate path resolution issues rather than actual missing files.