add script to retrieve supported Python versions, optionally from package source metadata

Author: zacharyburnett

.github/workflows/tox.yml

@@ -123,6 +123,17 @@ jobs:
       - uses: actions/setup-python@e797f83bcb11b83ae66e0230d6156d7c80228e7c # v6.0.0
         with:
           python-version: '3.12'
+      - if: inputs.envs == ''
+        run: echo $SUPPORTED_PYTHONS_SCRIPT | base64 --decode > supported_pythons.py
+        env:
+          SUPPORTED_PYTHONS_SCRIPT: IyAvLy8gc2NyaXB0CiMgcmVxdWlyZXMtcHl0aG9uID0gIj49My4xMiIKIyBkZXBlbmRlbmNpZXMgPSBbCiMgICAgICJjbGljaz09OC4yLjEiLAojICAgICAicGVwcHlwcm9qZWN0PT0xLjAuMiIsCiMgICAgICJyZXF1ZXN0cz09Mi4zMi41IiwKIyAgICAgInBhY2thZ2luZz09MjUuMCIsCiMgXQojIC8vLwoKaW1wb3J0IGpzb24KaW1wb3J0IG9zCmZyb20gcGF0aGxpYiBpbXBvcnQgUGF0aAppbXBvcnQgd2FybmluZ3MKCmltcG9ydCBjbGljawppbXBvcnQgcmVxdWVzdHMKZnJvbSBwYWNrYWdpbmcuc3BlY2lmaWVycyBpbXBvcnQgU3BlY2lmaWVyU2V0CmZyb20gcGFja2FnaW5nLnZlcnNpb24gaW1wb3J0IFZlcnNpb24KZnJvbSBwZXBweXByb2plY3QgaW1wb3J0IFB5UHJvamVjdENvbmZpZ3VyYXRpb24KCgpAY2xpY2suY29tbWFuZCgpCkBjbGljay5vcHRpb24oIi0tc291cmNlIiwgZGVmYXVsdD1Ob25lKQpAY2xpY2sub3B0aW9uKCItLWZsYWdzIiwgZGVmYXVsdD1Ob25lKQpAY2xpY2sub3B0aW9uKCItLW5vLWVvYXMiLCBpc19mbGFnPVRydWUsIGRlZmF1bHQ9RmFsc2UpCmRlZiBwcmludF9zdXBwb3J0ZWRfcHl0aG9ucygKICAgIHNvdXJjZTogUGF0aCA9IE5vbmUsCiAgICBmbGFnczogbGlzdFtzdHJdID0gTm9uZSwKICAgIG5vX2VvYXM6IGJvb2wgPSBGYWxzZSwKKToKICAgICIiImVudW1lcmF0ZSB0b3hlbnZzIFB5dGhvbiBmcm9tIGEgcGFja2FnZSBzb3VyY2UiIiIKCiAgICB0b3hlbnZzID0gc3VwcG9ydGVkX3B5dGhvbl90b3hlbnZzKHNvdXJjZSwgZmxhZ3MsIG5vX2VvYXMpCiAgICBwcmludChqc29uLmR1bXBzKHRveGVudnMsIGluZGVudD0yKSkKICAgIHdpdGggb3Blbihvcy5lbnZpcm9uWyJHSVRIVUJfT1VUUFVUIl0sICJhIikgYXMgZjoKICAgICAgICBmLndyaXRlKGYiZW52cz17anNvbi5kdW1wcyh0b3hlbnZzKX1cbiIpCgoKZGVmIHN1cHBvcnRlZF9weXRob25fdG94ZW52cygKICAgIHNvdXJjZTogUGF0aCA9IE5vbmUsCiAgICBmbGFnczogbGlzdFtzdHJdID0gTm9uZSwKICAgIG5vX2VvYXM6IGJvb2wgPSBGYWxzZSwKKSAtPiBsaXN0W3N0cl06CiAgICBweXRob25zID0gY3VycmVudF9weXRob25fdmVyc2lvbnMobm9fZW9hcz1ub19lb2FzKQoKICAgIGlmIHNvdXJjZSBpcyBOb25lIG9yIHNvdXJjZSA9PSAiIjoKICAgICAgICBzdXBwb3J0ZWRfcHl0aG9ucyA9IHB5dGhvbnMKICAgIGVsc2U6CiAgICAgICAgY29uZmlndXJhdGlvbiA9IFB5UHJvamVjdENvbmZpZ3VyYXRpb24uZnJvbV9kaXJlY3Rvcnkoc291cmNlKQogICAgICAgIHRyeToKICAgICAgICAgICAgcHl0aG9uX3JlcXVpcmVtZW50cyA9IFNwZWNpZmllclNldChjb25maWd1cmF0aW9uWyJwcm9qZWN0Il1bInJlcXVpcmVzLXB5dGhvbiJdKQoKICAgICAgICAgICAgc3VwcG9ydGVkX3B5dGhvbnMgPSBbcHl0aG9uIGZvciBweXRob24gaW4gcHl0aG9ucyBpZiBweXRob24gaW4gcHl0aG9uX3JlcXVpcmVtZW50c10KICAgICAgICBleGNlcHQgKEtleUVycm9yLCBUeXBlRXJyb3IpOgogICAgICAgICAgICB3YXJuaW5ncy53YXJuKCJjb3VsZCBub3QgZmluZCBgcmVxdWlyZXMtcHl0aG9uYCBpbiBtZXRhZGF0YTsgZmFsbGluZyBiYWNrIHRvIGN1cnJlbnQgUHl0aG9uIHZlcnNpb25zLi4uIikKICAgICAgICAgICAgc3VwcG9ydGVkX3B5dGhvbnMgPSBweXRob25zCgogICAgcmV0dXJuIFsKICAgICAgICBmInB5e3N0cihweXRob24pLnJlcGxhY2UoJy4nLCAnJyl9eyctJyArICctJy5qb2luKGZsYWdzKSBpZiBmbGFncyBpcyBub3QgTm9uZSBhbmQgbGVuKGZsYWdzKSA+IDAgZWxzZSAnJ30iCiAgICAgICAgZm9yIHB5dGhvbiBpbiBzdXBwb3J0ZWRfcHl0aG9ucwogICAgXQoKCmRlZiBjdXJyZW50X3B5dGhvbl92ZXJzaW9ucyhub19lb2FzOiBib29sID0gRmFsc2UpIC0+IGxpc3RbVmVyc2lvbl06CiAgICB1cmwgPSAiaHR0cHM6Ly9lbmRvZmxpZmUuZGF0ZS9hcGkvdjEvcHJvZHVjdHMvcHl0aG9uIgogICAgcmVzcG9uc2UgPSByZXF1ZXN0cy5nZXQoImh0dHBzOi8vZW5kb2ZsaWZlLmRhdGUvYXBpL3YxL3Byb2R1Y3RzL3B5dGhvbiIpCiAgICBpZiByZXNwb25zZS5zdGF0dXNfY29kZSA9PSAyMDA6CiAgICAgICAgcmV0dXJuIFsKICAgICAgICAgICAgVmVyc2lvbihweXRob25bIm5hbWUiXSkKICAgICAgICAgICAgZm9yIHB5dGhvbiBpbiByZXNwb25zZS5qc29uKClbInJlc3VsdCJdWyJyZWxlYXNlcyJdCiAgICAgICAgICAgIGlmIG5vdCBweXRob25bImlzRW9hcyIgaWYgbm9fZW9hcyBlbHNlICJpc0VvbCJdCiAgICAgICAgXQogICAgZWxzZToKICAgICAgICByYWlzZSBWYWx1ZUVycm9yKGYicmVxdWVzdCByZXR1cm5lZCBzdGF0dXMgY29kZSB7cmVzcG9uc2Uuc3RhdHVzX2NvZGV9IFt7dXJsfV0iKQoKCmlmIF9fbmFtZV9fID09ICJfX21haW5fXyI6CiAgICBwcmludF9zdXBwb3J0ZWRfcHl0aG9ucygpCg==
+      - if: inputs.envs == ''
+        run: cat supported_pythons.py
+      - id: get-envs
+        run: |
+          pipx run supported_pythons.py
+        shell: sh
+      - run: cat ${{ steps.get-envs.outputs.envs }}
       - run: echo $TOX_MATRIX_SCRIPT | base64 --decode > tox_matrix.py
         env:
           TOX_MATRIX_SCRIPT: # /// script
# requires-python = "==3.12"
# dependencies = [
#     "click==8.2.1",
#     "pyyaml==6.0.2",
# ]
# ///
import json
import os
import re

import click
import yaml


@click.command()
@click.option("--envs", default="")
@click.option("--libraries", default="")
@click.option("--posargs", default="")
@click.option("--toxdeps", default="")
@click.option("--toxargs", default="")
@click.option("--pytest", default="true")
@click.option("--pytest-results-summary", default="false")
@click.option("--coverage", default="")
@click.option("--conda", default="auto")
@click.option("--setenv", default="")
@click.option("--display", default="false")
@click.option("--cache-path", default="")
@click.option("--cache-key", default="")
@click.option("--cache-restore-keys", default="")
@click.option("--artifact-path", default="")
@click.option("--runs-on", default="")
@click.option("--default-python", default="")
@click.option("--timeout-minutes", default="360")
def load_tox_targets(envs, libraries, posargs, toxdeps, toxargs, pytest, pytest_results_summary,
                     coverage, conda, setenv, display, cache_path, cache_key,
                     cache_restore_keys, artifact_path, runs_on, default_python, timeout_minutes):
    """Script to load tox targets for GitHub Actions workflow."""
    # Load envs config
    envs = yaml.load(envs, Loader=yaml.BaseLoader)
    print(json.dumps(envs, indent=2))

    # Load global libraries config
    global_libraries = {
        "brew": [],
        "brew-cask": [],
        "apt": [],
        "choco": [],
    }
    libraries = yaml.load(libraries, Loader=yaml.BaseLoader)
    if libraries is not None:
        global_libraries.update(libraries)
    print(json.dumps(global_libraries, indent=2))

    # Default images to use for runners
    default_runs_on = {
        "linux": "ubuntu-latest",
        "macos": "macos-latest",
        "windows": "windows-latest",
    }
    custom_runs_on = yaml.load(runs_on, Loader=yaml.BaseLoader)
    if isinstance(custom_runs_on, dict):
        default_runs_on.update(custom_runs_on)
    print(json.dumps(default_runs_on, indent=2))

    # Default string parameters which can be overwritten by each env
    string_parameters = {
        "posargs": posargs,
        "toxdeps": toxdeps,
        "toxargs": toxargs,
        "pytest": pytest,
        "pytest-results-summary": pytest_results_summary,
        "coverage": coverage,
        "conda": conda,
        "setenv": setenv,
        "display": display,
        "cache-path": cache_path,
        "cache-key": cache_key,
        "cache-restore-keys": cache_restore_keys,
        "artifact-path": artifact_path,
        "timeout-minutes": timeout_minutes,
    }

    # Create matrix
    matrix = {"include": []}
    for env in envs:
        matrix["include"].append(get_matrix_item(
            env,
            global_libraries=global_libraries,
            global_string_parameters=string_parameters,
            runs_on=default_runs_on,
            default_python=default_python,
        ))

    # Output matrix
    print(json.dumps(matrix, indent=2))
    with open(os.environ["GITHUB_OUTPUT"], "a") as f:
        f.write(f"matrix={json.dumps(matrix)}\n")


def get_matrix_item(env, global_libraries, global_string_parameters,
                    runs_on, default_python):

    # define spec for each matrix include (+ global_string_parameters)
    item = {
        "os": None,
        "toxenv": None,
        "python_version": None,
        "name": None,
        "pytest_flag": None,
        "libraries_brew": None,
        "libraries_brew_cask": None,
        "libraries_apt": None,
        "libraries_choco": None,
        "cache-path": None,
        "cache-key": None,
        "cache-restore-keys": None,
        "artifact-name": None,
        "artifact-path": None,
        "timeout-minutes": None,
    }
    for string_param, default in global_string_parameters.items():
        env_value = env.get(string_param)
        item[string_param] = default if env_value is None else env_value

    # set os and toxenv
    for k, v in runs_on.items():
        if k in env:
            platform = k
            item["os"] = env.get("runs-on", v)
            item["toxenv"] = env[k]
    assert item["os"] is not None and item["toxenv"] is not None

    # set python_version
    python_version = env.get("python-version")
    m = re.search("^py(2|3)([0-9]+t?)", item["toxenv"])
    if python_version is not None:
        item["python_version"] = python_version
    elif m is not None:
        major, minor = m.groups()
        item["python_version"] = f"{major}.{minor}"
    else:
        item["python_version"] = env.get("default_python") or default_python

    # set name
    item["name"] = env.get("name") or f'{item["toxenv"]} ({item["os"]})'

    # set artifact-name (replace invalid path characters)
    item["artifact-name"] = re.sub(r"[\\ /:<>|*?\"']", "-", item["name"])
    item["artifact-name"] = re.sub(r"-+", "-", item["artifact-name"])

    # set pytest_flag
    item["pytest_flag"] = ""
    sep = r"\\" if platform == "windows" else "/"
    if item["pytest"] == "true" and "codecov" in item.get("coverage", ""):
        item["pytest_flag"] += (
            rf"--cov-report=xml:${{GITHUB_WORKSPACE}}{sep}coverage.xml ")
    if item["pytest"] == "true" and item["pytest-results-summary"] == "true":
        item["pytest_flag"] += rf"--junitxml ${{GITHUB_WORKSPACE}}{sep}results.xml "

    # set libraries
    env_libraries = env.get("libraries")
    if isinstance(env_libraries, str) and len(env_libraries.strip()) == 0:
        env_libraries = {}  # no libraries requested for environment
    libraries = global_libraries if env_libraries is None else env_libraries
    for manager in ["brew", "brew_cask", "apt", "choco"]:
        item[f"libraries_{manager}"] = " ".join(libraries.get(manager, []))

    # set "auto" conda value
    if item["conda"] == "auto":
        item["conda"] = "true" if "conda" in item["toxenv"] else "false"

    # inject toxdeps for conda
    if item["conda"] == "true" and "tox-conda" not in item["toxdeps"].lower():
        item["toxdeps"] = ("tox-conda " + item["toxdeps"]).strip()

    # make timeout-minutes a number
    item["timeout-minutes"] = int(item["timeout-minutes"])

    # verify values
    assert item["pytest"] in {"true", "false"}
    assert item["conda"] in {"true", "false"}
    assert item["display"] in {"true", "false"}

    return item


if __name__ == "__main__":
    load_tox_targets()


tools/supported_pythons.py

@@ -0,0 +1,79 @@
+# /// script
+# requires-python = ">=3.12"
+# dependencies = [
+#     "click==8.2.1",
+#     "peppyproject==1.0.2",
+#     "requests==2.32.5",
+#     "packaging==25.0",
+# ]
+# ///
+
+import json
+import os
+from pathlib import Path
+import warnings
+
+import click
+import requests
+from packaging.specifiers import SpecifierSet
+from packaging.version import Version
+from peppyproject import PyProjectConfiguration
+
+
+@click.command()
+@click.option("--source", default=None)
+@click.option("--flags", default=None)
+@click.option("--no-eoas", is_flag=True, default=False)
+def print_supported_pythons(
+    source: Path = None,
+    flags: list[str] = None,
+    no_eoas: bool = False,
+):
+    """enumerate toxenvs Python from a package source"""
+
+    toxenvs = supported_python_toxenvs(source, flags, no_eoas)
+    print(json.dumps(toxenvs, indent=2))
+    with open(os.environ["GITHUB_OUTPUT"], "a") as f:
+        f.write(f"envs={json.dumps(toxenvs)}\n")
+
+
+def supported_python_toxenvs(
+    source: Path = None,
+    flags: list[str] = None,
+    no_eoas: bool = False,
+) -> list[str]:
+    pythons = current_python_versions(no_eoas=no_eoas)
+
+    if source is None or source == "":
+        supported_pythons = pythons
+    else:
+        configuration = PyProjectConfiguration.from_directory(source)
+        try:
+            python_requirements = SpecifierSet(configuration["project"]["requires-python"])
+
+            supported_pythons = [python for python in pythons if python in python_requirements]
+        except (KeyError, TypeError):
+            warnings.warn("could not find `requires-python` in metadata; falling back to current Python versions...")
+            supported_pythons = pythons
+
+    return [
+        f"py{str(python).replace('.', '')}{'-' + '-'.join(flags) if flags is not None and len(flags) > 0 else ''}"
+        for python in supported_pythons
+    ]
+
+
+def current_python_versions(no_eoas: bool = False) -> list[Version]:
+    url = "https://endoflife.date/api/v1/products/python"
+    response = requests.get("https://endoflife.date/api/v1/products/python")
+    if response.status_code == 200:
+        return [
+            Version(python["name"])
+            for python in response.json()["result"]["releases"]
+            if not python["isEoas" if no_eoas else "isEol"]
+        ]
+    else:
+        raise ValueError(f"request returned status code {response.status_code} [{url}]")
+
+
+if __name__ == "__main__":
+    print_supported_pythons()

update_scripts_in_yml.py

@@ -32,3 +32,4 @@ def base64_encode_into(script, yml_file, env_var):
 base64_encode_into('set_env.py', 'tox.yml', 'SET_ENV_SCRIPT')
 base64_encode_into('set_env.py', 'publish.yml', 'SET_ENV_SCRIPT')
 base64_encode_into('set_env.py', 'publish_pure_python.yml', 'SET_ENV_SCRIPT')
+base64_encode_into('supported_pythons.py', 'tox.yml', 'SUPPORTED_PYTHONS_SCRIPT')