Code Inspections in Dockerfile

This topic lists all JetBrains Rider code inspections available in Dockerfile.

You can toggle specific inspections or change their severity level on the Editor | Inspection Settings | Inspection Severity | Other Languages page of the IDE settings Ctrl+Alt+S.

Inspection	Description	Default Severity
Invalid destination for ''ADD''/''COPY'' commands	Reports invalid destination directories in `ADD` and `COPY` commands. According to the Dockerfile specification, if multiple sources are specified, then the destination must be a directory, and it must end with a slash '/'. Otherwise, Docker build will fail. Examples: # all the commands below will fail ADD textA.txt textB.txt relativeDir ADD ["binaryA.jar", "binary2.jar", "destination"] COPY text3.txt text4.txt /absolute/path After the quick-fix is applied: ADD textA.txt textB.txt relativeDir/ ADD ["binaryA.jar", "binary2.jar", "destination/"] COPY text3.txt text4.txt /absolute/path/	Warning
Invalid spaces in ''key=value'' pair	Reports incorrect spacing for key-value pairs in `ARG`, `ENV`, and `LABEL` commands. While it is not explicitly specified in the Dockerfile specification, some combinations of spacing for key-value pairs are not allowed. Docker build will fail after reaching the problem instruction. Examples: The `ARG` command does not allow any spaces around '=' `ENV` and `LABEL` do not allow spaces after '=' # all the commands below will fail ARG answer = 42 ARG version= "1.0.0" LABEL "maintained.by"= someone@gmail.com ENV JAVA_HOME= "/docker-java-home" After the quick-fix is applied: ARG answer=2 ARG version="1.0.0" LABEL "maintained.by"=someone@gmail.com ENV JAVA_HOME="/docker-java-home"	Error
Wrong number of arguments	Reports invalid number of arguments for the Dockerfile commands. Docker build will fail after reaching the instruction with an invalid number of arguments.	Error

Inspection

Description

Default Severity

Invalid destination for ''ADD''/''COPY'' commands

Reports invalid destination directories in ADD and COPY commands.

According to the Dockerfile specification, if multiple sources are specified, then the destination must be a directory, and it must end with a slash '/'. Otherwise, Docker build will fail.

Examples:

  # all the commands below will fail
  ADD textA.txt textB.txt relativeDir
  ADD ["binaryA.jar", "binary2.jar", "destination"]
  COPY text3.txt text4.txt /absolute/path

After the quick-fix is applied:

  ADD textA.txt textB.txt relativeDir/
  ADD ["binaryA.jar", "binary2.jar", "destination/"]
  COPY text3.txt text4.txt /absolute/path/

Warning

Invalid spaces in ''key=value'' pair

Reports incorrect spacing for key-value pairs in ARG, ENV, and LABEL commands.

While it is not explicitly specified in the Dockerfile specification, some combinations of spacing for key-value pairs are not allowed. Docker build will fail after reaching the problem instruction.

Examples:

The ARG command does not allow any spaces around '='
ENV and LABEL do not allow spaces after '='

  # all the commands below will fail
  ARG answer = 42
  ARG version= "1.0.0"
  LABEL "maintained.by"= someone@gmail.com
  ENV JAVA_HOME= "/docker-java-home"

After the quick-fix is applied:

  ARG answer=2
  ARG version="1.0.0"
  LABEL "maintained.by"=someone@gmail.com
  ENV JAVA_HOME="/docker-java-home"

Error

Wrong number of arguments

Reports invalid number of arguments for the Dockerfile commands.

Docker build will fail after reaching the instruction with an invalid number of arguments.

Error

Last modified: 16 July 2021