Dockerfile Parse

2.0.1 · active · verified Thu Apr 09

Dockerfile Parse is a Python library designed for programmatic manipulation and parsing of Dockerfile files. It provides structured access to Dockerfile instructions, making it suitable for tasks like static analysis, linting, and automated tooling around Docker container builds. The library is actively maintained, with version 2.0.1 being the current release, and it frequently receives updates for compatibility with newer Python versions.

Warnings

breaking Python 2 support was completely dropped in version 2.0.0. Applications running on Python 2.x will fail to import or run `dockerfile-parse` version 2.0.0 or newer.
Fix: Upgrade your Python environment to Python 3.6 or newer. The `requires_python` specifies `>=3.6`.
breaking Support for Python 2.6 was dropped in version 0.0.14.
Fix: Ensure your Python 2 environment is at least Python 2.7 if you must use an older version of the library (pre-2.0.0).
gotcha Older versions of `dockerfile-parse` (prior to 1.1.0) do not properly support the `escape` directive in Dockerfiles.
Fix: Upgrade to `dockerfile-parse` version 1.1.0 or newer to correctly parse Dockerfiles that utilize the `escape` directive.
gotcha Handling of multi-line instructions, specifically with the `add_lines_at()` method, had issues in versions prior to 0.0.14.
Fix: Update to version 0.0.14 or newer to ensure correct processing of multi-line instructions when programmatically adding lines to a Dockerfile.
gotcha Error reporting for incorrect LABEL syntax was improved in version 0.0.15. Older versions might provide less descriptive errors or unexpected behavior for malformed LABEL instructions.
Fix: Upgrade to version 0.0.15 or later for more robust error handling and clearer diagnostics when dealing with potentially incorrect LABEL syntax.

Install

pip install dockerfile-parse Install from PyPI

Imports

DockerfileParser

from dockerfile_parse import DockerfileParser

Quickstart

Initialize a `DockerfileParser` instance, load Dockerfile content as a string, and then access or modify its parsed elements such as the structure, labels, or the base image. The `content` attribute can be used to read or write the full Dockerfile string.

from pprint import pprint
from dockerfile_parse import DockerfileParser

dfp = DockerfileParser()
dfp.content = """
FROM base
LABEL foo="bar baz"
USER me
"""

# Print the parsed structure:
print("--- Structure ---")
pprint(dfp.structure)

# Print labels:
print("\n--- Labels ---")
pprint(dfp.labels)

# Set a new base image:
dfp.baseimage = 'centos:7'

# Print the new Dockerfile content with an updated FROM line:
print("\n--- Updated Dockerfile Content ---")
print(dfp.content)

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