Feature update: ENV VARs in Dockerfile Linter
Being a Docker-based tool itself, Buddy provides everything you need to build, test, and orchestrate Docker images:
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One of these actions is Dockerfile Linter, a handy tool that lets you check the Dockerfile syntax before building the image. The tool follows the best practices from the official Docker website so that you can be sure your images are optimized for maximum performance.
With this week's release the action has received support for environment variables, a nifty feature that will help you better organize your Docker workflows.
Example use case
You can use ENV VARs to store the path to the Dockerfile. First, you need to add the path to the variable in the Variables tab:
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The you simply enter the variable name in the Linter's Dockerfile input path:
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Ignore tab of the action details.
Placing the action before the build and adding a conditional notification will keep you on toes in case Buddy detects errors with the Dockerfile:
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Rules table
| Rules | Description |
|---|---|
EL0001 | Invalid line |
ED0001 | All parser directives must be at the very top of a Dockerfile. |
ED0002 | Directive appears more then once. |
ED0003 | Directives should be lowercase. |
ED0004 | Parser directive will be treated as a comment. |
ED0005 | Missing value for directive. |
ER0001 | Set the SHELL option -o (-eo for Alpine image) pipefail before RUN with a pipe in. |
EU0001 | Last user should not be root. |
EI0001 | There can only be one instruction like (CMD, HEALTHCHECK, ENTRYPOINT). |
EI0002 | FROM may only be preceded by one or more ARG. |
EF0001 | Missing FROM. |
EC0001 | COPY --from cannot reference its own FROM alias. |
EC0002 | COPY --from should reference a previously defined FROM alias. |
EI0003 | MAINTAINER is deprecated, instead use LABEL. |
EJ0001 | You must use double-quotes (") in JSON array. |
EJ0002 | CMD and ENTRYPOINT should be written in JSON form. |
EJ0003 | SHELL must be written in JSON form. |
EF0002 | FROM aliases must be unique. |
EF0003 | Using latest is prone to errors if the image will ever update. |
EF0004 | Always tag the version of an image explicitly. |
ER0002 | Delete the apt-get lists after installing something. |
ER0003 | Use WORKDIR to switch to a directory. |
ER0004 | Do not use sudo, consider using gosu. |
ER0005 | Command (ssh, vim, shutdown, service, ps, free, top, kill, mount, ifconfig) does not make sense in a container. |
ER0006 | Using (apt-get upgrade, dist-upgrade, apk upgrade, apt install) is not recommended. |
EA0001 | Use curl or wget instead, and delete files when no longer needed. |
EC0003 | Use ADD for extracting archives into a image. |
ER0007 | Either use wget or curl, but not both. |
ER0008 | Use SHELL to change the default shell. |
ER0009 | Use the -y switch. |
ER0010 | Avoid additional packages by specifying --no-install-recommends. |
EA0002 | Use COPY instead of ADD for files and folders. |
EC0004 | COPY with more then 2 arguments requires the last argument to end with /. |
ER0011 | Use the --no-cache switch. |
ER0012 | Pin versions in apt get install. |
ER0013 | Pin versions in pip install. |
ER0014 | Pin versions in npm install. |
ER0015 | Pin versions in apk add. |
ER0016 | Pin versions in gem install. |
EI0004 | Don't use (ONBUILD,FROM,MAINTAINTER) in ONBUILD. |
EW0001 | Use absolute WORKDIR. |
EE0001 | Valid UNIX ports range from 0 to 65535. |
EI0005 | Instructions should be uppercase. |
Jarek Dylewski
Customer Support
A journalist and an SEO specialist trying to find himself in the unforgiving world of coders. Gamer, a non-fiction literature fan and obsessive carnivore. Jarek uses his talents to convert the programming lingo into a cohesive and approachable narration.