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replicatedhq / dockerfilelint

An opinionated Dockerfile linter.
https://www.fromlatest.io
MIT License
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Help understanding comment issues at line 1 in Dockerfile #155

Closed AmauryOrtega closed 3 years ago

AmauryOrtega commented 3 years ago

I'm using the latest docker image replicated/dockerfilelint:latest to test my Dockerfile and I'm getting this output (First try). I do not understand which comment is raising this issue. I thought it was the comments on line 3 and 4 so I removed then and tried again but no luck (Second try).

Can someone explain to me what is happening here?

First try

Dockerfile

FROM node:12-alpine

# Use latest stable npm
# RUN npm install -g npm@latest

# Install:
# hadolint ignore=DL3016,DL3018
RUN npm install --no-optional --quiet --yes -g \
        pm2 \
    && apk --no-cache add curl \
    && rm -rf /var/cache/apk/*

# Source directory
ENV APP_DIR=/usr/src/app/
RUN mkdir -p ${APP_DIR} && chown -R node:node ${APP_DIR}
WORKDIR ${APP_DIR}

# Dropping privileges
USER node

# Install dependencies
# CI=True, Disables progress bars https://docs.npmjs.com/misc/config#progress
ENV CI=true
COPY --chown=node:node package* ./
RUN npm ci --no-optional --quiet --yes && npm prune --production

# Code
COPY --chown=node:node . .

USER root
# Entrypoint and wait script
ADD https://github.com/ufoscout/docker-compose-wait/releases/download/2.7.3/wait /bin/wait
COPY docker-entrypoint.sh /bin/docker-entrypoint.sh
RUN chmod +x /bin/wait /bin/docker-entrypoint.sh
ENTRYPOINT [ "/bin/docker-entrypoint.sh" ]

# Default execution
EXPOSE 8080
ENV HOST=0.0.0.0 PORT=8080 NODE_ENV=production

# HEALTHCHECK CMD curl -f http://localhost:"$PORT"/healthcheck || exit 1

USER node
# Run pm2 on foreground
CMD ["pm2-runtime", "start", "ecosystem.config.js"]

Output

$ docker run --rm -v "$PWD"/Dockerfile:/Dockerfile replicated/dockerfilelint:latest Dockerfile
File:   <contents>
Issues: 4
Line 1: Dockerfile
Issue  Category      Title                 Description
    1  Possible Bug  Missing Required      All commands in a Dockerfile require at least 1 argument.
                     Arguments             A line in a Dockerfile can be in any of the following formats:
                                           * * *
                                           #### `# Comment`
                                           Docker will treat any line that begins with a `#` as a comment.
                                           * * *
                                           #### `INSTRUCTION arguments`
                                           All instructions require at least 1 argument, and should be on the
                                           same line as the `INSTRUCTION`.
                                           * * *
                                           #### `RUN` continuation
                                           If a `RUN` line ends with a `\`, the next line will be treated as
                                           part of the same `RUN` arguement.
                                           * * *
                                           #### Blank or Whitespace
                                           Blank lines are allowed and will be ignored.
                                           * * *
    2  Clarity       Capitalize            For clarity and readability, all instructions in a Dockerfile
                     Dockerfile            should be uppercase.
                     Instructions          This is a convention adopted by most of the official images and
                                           greatly improves readability in long Dockerfiles.  For an example
                                           of
                                           why this makes a difference, check out the current [redis
                                           Dockerfile](https://github.com/docker-library/redis/blob/b375650fb6
                                           9b7db819e90c0033433c705b28656e/3.0/Dockerfile)
                                           and you should be able to easily see the instructions used.
    3  Possible Bug  First Command Must    The first instruction in a Dockerfile must specify the base image
                     Be FROM or ARG        using a FROM command or an ARG command to modify the FROM command.
                                           Additionally, FROM cannot appear later in a Dockerfile.
    4  Possible Bug  Invalid Line          This line is not a valid Dockerfile line.

First try

Dockerfile

FROM node:12-alpine

# Install:
# hadolint ignore=DL3016,DL3018
RUN npm install --no-optional --quiet --yes -g \
        pm2 \
    && apk --no-cache add curl \
    && rm -rf /var/cache/apk/*

# Source directory
ENV APP_DIR=/usr/src/app/
RUN mkdir -p ${APP_DIR} && chown -R node:node ${APP_DIR}
WORKDIR ${APP_DIR}

# Dropping privileges
USER node

# Install dependencies
# CI=True, Disables progress bars https://docs.npmjs.com/misc/config#progress
ENV CI=true
COPY --chown=node:node package* ./
RUN npm ci --no-optional --quiet --yes && npm prune --production

# Code
COPY --chown=node:node . .

USER root
# Entrypoint and wait script
ADD https://github.com/ufoscout/docker-compose-wait/releases/download/2.7.3/wait /bin/wait
COPY docker-entrypoint.sh /bin/docker-entrypoint.sh
RUN chmod +x /bin/wait /bin/docker-entrypoint.sh
ENTRYPOINT [ "/bin/docker-entrypoint.sh" ]

# Default execution
EXPOSE 8080
ENV HOST=0.0.0.0 PORT=8080 NODE_ENV=production

# HEALTHCHECK CMD curl -f http://localhost:"$PORT"/healthcheck || exit 1

USER node
# Run pm2 on foreground
CMD ["pm2-runtime", "start", "ecosystem.config.js"]

Output

$ docker run --rm -v "$PWD"/Dockerfile:/Dockerfile replicated/dockerfilelint:latest Dockerfile
File:   <contents>
Issues: 4
Line 1: Dockerfile
Issue  Category      Title                 Description
    1  Possible Bug  Missing Required      All commands in a Dockerfile require at least 1 argument.
                     Arguments             A line in a Dockerfile can be in any of the following formats:
                                           * * *
                                           #### `# Comment`
                                           Docker will treat any line that begins with a `#` as a comment.
                                           * * *
                                           #### `INSTRUCTION arguments`
                                           All instructions require at least 1 argument, and should be on the
                                           same line as the `INSTRUCTION`.
                                           * * *
                                           #### `RUN` continuation
                                           If a `RUN` line ends with a `\`, the next line will be treated as
                                           part of the same `RUN` arguement.
                                           * * *
                                           #### Blank or Whitespace
                                           Blank lines are allowed and will be ignored.
                                           * * *
    2  Clarity       Capitalize            For clarity and readability, all instructions in a Dockerfile
                     Dockerfile            should be uppercase.
                     Instructions          This is a convention adopted by most of the official images and
                                           greatly improves readability in long Dockerfiles.  For an example
                                           of
                                           why this makes a difference, check out the current [redis
                                           Dockerfile](https://github.com/docker-library/redis/blob/b375650fb6
                                           9b7db819e90c0033433c705b28656e/3.0/Dockerfile)
                                           and you should be able to easily see the instructions used.
    3  Possible Bug  First Command Must    The first instruction in a Dockerfile must specify the base image
                     Be FROM or ARG        using a FROM command or an ARG command to modify the FROM command.
                                           Additionally, FROM cannot appear later in a Dockerfile.
    4  Possible Bug  Invalid Line          This line is not a valid Dockerfile line.
marccampbell commented 3 years ago

@AmauryOrtega I've copied the Dockerfile locally and tried it here, and it reports 

Issues: None found 👍

Could you share some details of the command line you are using to execute the linting?

AmauryOrtega commented 3 years ago

@marccampbell Thanks for your help, the command line I used is in the output section on my previous comment.

Because it's been a while I didn't focus on this, I was able to come back with a clear mind and I just now realized that it was my mistake.

The replicated/dockerfilelint's dockerfile clearly states that the workdir is set to /dockerfilelint

I assumed the workdir was / so I placed the Dockerfile in /Dockerfile and tried calling it. That's why the tool was outputting File: <contents>.

I changed my command to 

$ docker run --rm -v "$PWD"/Dockerfile:/dockerfilelint/Dockerfile replicated/dockerfilelint:latest Dockerfile
File:   Dockerfile
Issues: None found 👍

It also would've worked if I just followed the README.md as intended.