CODEWITHSUNDEEP
dockerdockerfile
user674669
user674669

Reputation: 12392

How to show the full (not truncated) "CREATED BY" commands in "docker history" output?

How can I show the full command in the third column (CREATED BY) in the docker history output?

$ $ docker history python
IMAGE          CREATED       CREATED BY                                      SIZE      COMMENT
69ee9abe2bda   5 weeks ago   CMD ["python3"]                                 0B        buildkit.dockerfile.v0
<missing>      5 weeks ago   RUN /bin/sh -c set -eux;   wget -O get-pip.p…   10MB      buildkit.dockerfile.v0
<missing>      5 weeks ago   ENV PYTHON_GET_PIP_SHA256=22b849a10f86f5ddf7…   0B        buildkit.dockerfile.v0
...

The CREATED BY is truncating/abbreviating the commands which makes it hard to reconstruct the original Dockerfile. How do I get the full CREATED BY commands?

Upvotes: 63

Views: 41154

Answers (2)

Alassane Ndiaye
Alassane Ndiaye

Reputation: 4777

Use the docker history --no-trunc option to show the full command.

Upvotes: 85

Rich Lysakowski PhD
Rich Lysakowski PhD

Reputation: 3113

I needed to see the full build history without truncated build steps in a tabular format for debugging purposes. The Docker Docs examples are often incomplete (or non-existent). The accepted answer by @Alassane_Hdiaye can work, but throws an error if used in the wrong place. After a couple tries, I got the GoLang template table formatter to produce the result I needed.

The Docker GoLang template --format option works with docker history, but must be entered AFTER --format, because it modifies --format, NOT docker history. The docker history command takes only 1 argument. The --format option changes the output of docker history, and --no-trunc modifies the --format option.

The command sequence must be

docker history <image-id> --format <GoLang template spec> --no-trunc

The --no-trunc option follows --format on the command line, because it modifies the --format option.

So for the fully history in a tabular format:

docker history <image-id> --format "table{{.ID}}, {{.CreatedBy}}" --no-trunc

The output is messy, because Dockerfile RUN commands can wrap many lines.

So pipe the result to a CSV file and open it in Excel (for lack of a better table viewer). 

docker history <image-id> --format "table{{.ID}}, {{.CreatedBy}}" --no-trunc > image-id-history.csv

So now I can see complete build instructions in Excel without truncation.

As a side note, Docker history does not output RUN and other dockerfile build keywords, but these can be inferred. But at least full commands from the complete history are available.

Upvotes: 20

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