Open source

Apply Docker best practices

Recipe IDorg.openrewrite.docker.DockerBestPractices

Artifactorg.openrewrite:rewrite-docker

Apply a set of Docker best practices to Dockerfiles. This recipe applies security hardening, build optimization, and maintainability improvements based on CIS Docker Benchmark and industry best practices.

Composite recipeOpenRewritedockerApache License Version 2.0

Try in PlatformTry this recipe in the Moderne platform. Not a user yet? You’ll get a no-setup demo environment, with nothing to install or configure.

Definition

Recipes4

• Apply Docker security best practices
• Optimize Docker builds
• Normalize Docker Hub image names
• Use exec form for ENTRYPOINT and CMD

Examples

docker

docker

Before

FROM ubuntu:20.04
ADD app.jar /app/
RUN apt-get update
RUN apt-get install -y curl
ENTRYPOINT /app/start.sh

After

~~(EOL: ubuntu:20.04 (ended 2025-05-31, suggest plucky (26.04)))~~>~~(Missing HEALTHCHECK instruction)~~>FROM ubuntu:20.04
COPY app.jar /app/
RUN apt-get update && apt-get install -y curl && rm -rf /var/lib/apt/lists/*
ENTRYPOINT ["/app/start.sh"]
USER appuser

Diff

@@ -1,5 +1,5 @@
-FROM ubuntu:20.04
-ADD app.jar /app/
-RUN apt-get update
-RUN apt-get install -y curl
-ENTRYPOINT /app/start.sh
+~~(EOL: ubuntu:20.04 (ended 2025-05-31, suggest plucky (26.04)))~~>~~(Missing HEALTHCHECK instruction)~~>FROM ubuntu:20.04
+COPY app.jar /app/
+RUN apt-get update && apt-get install -y curl && rm -rf /var/lib/apt/lists/*
+ENTRYPOINT ["/app/start.sh"]
+USER appuser

docker

docker

Before

FROM ubuntu:20.04
ADD app.jar /app/
RUN apt-get update
RUN apt-get install -y curl
ENTRYPOINT /app/start.sh

After

~~(EOL: ubuntu:20.04 (ended 2025-05-31, suggest plucky (26.04)))~~>~~(Missing HEALTHCHECK instruction)~~>FROM ubuntu:20.04
COPY app.jar /app/
RUN apt-get update && apt-get install -y curl && rm -rf /var/lib/apt/lists/*
ENTRYPOINT ["/app/start.sh"]
USER appuser

Diff

@@ -1,5 +1,5 @@
-FROM ubuntu:20.04
-ADD app.jar /app/
-RUN apt-get update
-RUN apt-get install -y curl
-ENTRYPOINT /app/start.sh
+~~(EOL: ubuntu:20.04 (ended 2025-05-31, suggest plucky (26.04)))~~>~~(Missing HEALTHCHECK instruction)~~>FROM ubuntu:20.04
+COPY app.jar /app/
+RUN apt-get update && apt-get install -y curl && rm -rf /var/lib/apt/lists/*
+ENTRYPOINT ["/app/start.sh"]
+USER appuser

Usage

Run this recipe

This recipe has no required configuration options. Users of Moderne can run it via the Moderne CLI.

You will need to have configured the Moderne CLI on your machine before you can run the following command.

shell

mod run . --recipe DockerBestPractices

If the recipe is not available locally, then you can install it using:

mod config recipes jar install org.openrewrite:rewrite-docker:8.87.1

Data tables

End-of-life Docker images

org.openrewrite.docker.table.EolDockerImages

Records Docker base images that have reached end-of-life.

Column	Description
Source file	The Dockerfile containing the EOL base image.
Stage name	The build stage name (from AS clause), if specified.
Image name	The name of the base image.
Tag	The image tag.
EOL date	The date when the image reached end-of-life.
Suggested replacement	Recommended newer version to migrate to.

Source files that had results

org.openrewrite.table.SourcesFileResults

Source files that were modified by the recipe run.

Column	Description
Source path before the run	The source path of the file before the run. null when a source file was created during the run.
Source path after the run	A recipe may modify the source path. This is the path after the run. null when a source file was deleted during the run.
Parent of the recipe that made changes	In a hierarchical recipe, the parent of the recipe that made a change. Empty if this is the root of a hierarchy or if the recipe is not hierarchical at all.
Recipe that made changes	The specific recipe that made a change.
Estimated time saving	An estimated effort that a developer to fix manually instead of using this recipe, in unit of seconds.
Cycle	The recipe cycle in which the change was made.

Source files that had search results

org.openrewrite.table.SearchResults

Search results that were found during the recipe run.

Column	Description
Source path of search result before the run	The source path of the file with the search result markers present.
Source path of search result after run the run	A recipe may modify the source path. This is the path after the run. null when a source file was deleted during the run.
Result	The trimmed printed tree of the LST element that the marker is attached to.
Description	The content of the description of the marker.
Recipe that added the search marker	The specific recipe that added the Search marker.

Source files that errored on a recipe

org.openrewrite.table.SourcesFileErrors

The details of all errors produced by a recipe run.

Column	Description
Source path	The file that failed to parse.
Recipe that made changes	The specific recipe that made a change.
Stack trace	The stack trace of the failure.

Recipe performance

org.openrewrite.table.RecipeRunStats

Statistics used in analyzing the performance of recipes.

Column	Description
The recipe	The recipe whose stats are being measured both individually and cumulatively.
Source file count	The number of source files the recipe ran over.
Source file changed count	The number of source files which were changed in the recipe run. Includes files created, deleted, and edited.
Cumulative scanning time (ns)	The total time spent across the scanning phase of this recipe.
Max scanning time (ns)	The max time scanning any one source file.
Cumulative edit time (ns)	The total time spent across the editing phase of this recipe.
Max edit time (ns)	The max time editing any one source file.