how to generate requirements.txt from BUILD file?

[jessehersch]

Hi pants experts!

Anyone know how to generate a python requirements.txt file from all the libs in 3rdparty/BUILD? I am using pants 2.15.0

in pants 1.3.0 (ancient I know 😊) I used to do this.

./pants dependencies2 --dependencies2-type=3rdparty :: | sort -u > ./requirements.txt

In 2.15 there does not seem to be an equivalent of the type arg:

`dependencies` goal options
---------------------------

List the dependencies of the input files/targets.
 
Activated by pants.backend.project_info
Config section: [dependencies]
 
  --dependencies-output-file=<path>
  PANTS_DEPENDENCIES_OUTPUT_FILE
  output_file
      default: None
      current value: None
      Output the goal's stdout to this file. If unspecified, outputs to stdout.

  --dependencies-sep=<separator>
  PANTS_DEPENDENCIES_SEP
  sep
      default: \n
      current value: \n
      String to use to separate lines in line-oriented output.

  --[no-]dependencies-transitive
  PANTS_DEPENDENCIES_TRANSITIVE
  transitive
      default: False
      current value: False
      List all transitive dependencies. If unspecified, list direct dependencies only.

  --[no-]dependencies-closed
  PANTS_DEPENDENCIES_CLOSED
  closed
      default: False
      current value: False
      Include the input targets in the output, along with the dependencies.

Jesse

[benjyw]

Interesting question. Typically there is already a requirements.txt from which the targets are generated. But it sounds like you have manual python_requirement targets or something like that?

Anyway, in v2 you can do something like:

./pants peek 3rdparty/python/:: | jq -r ".[].requirements | select( . != null ) | flatten[]"

[jessehersch]

I wanted this just so I could quickly setup a venv that has all the right dependencies installed for local dev.

[benjyw]

Gotcha! Well, ./pants peek 3rdparty/python/:: dumps out a ton of info, and then you can munge it with your favourite JSON manipulation tool. That jq example above should work.

[huonw]

For the specific task of creating a venv of a resolve's set of requirements, there's the pants export goal. There's some more details about it at https://www.pantsbuild.org/docs/setting-up-an-ide#python-third-party-dependencies-and-tools. Does that help with the overall task here?