#2: Rewrite as a composite action

action.py

@@ -0,0 +1,61 @@
+import os
+import subprocess
+
+
+def run_command(command: str) -> str:
+    print("Running command: {}".format(command))
+    result = subprocess.run(command, check=True, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
+    return result.stdout.decode("utf-8").strip()
+
+
+def set_output(name: str, value: str) -> None:
+    with open(os.environ["GITHUB_OUTPUT"], "a") as file:
+        file.write(["{}={}\n".format(name, value)])
+
+
+def export_variable(name: str, value: str) -> None:
+    print("Setting environment variable: {}".format(name))
+    with open(os.environ["GITHUB_ENV"], "a") as file:
+        file.write(["{}={}\n".format(name, value)])
+
+
+def set_failed(error: Exception) -> None:
+    print("::error::{}".format(error))
+
+    stdout = getattr(error, "stdout", None)
+    if stdout is not None:
+        print("stdout: {}".format(stdout))
+
+    stderr = getattr(error, "stderr", None)
+    if stderr is not None:
+        print("stderr: {}".format(stdout))
+
+
+def main() -> None:
+    install = os.environ["INPUT_INSTALL"]
+    env_var = os.environ["INPUT_ENV_VAR"]
+    command = os.environ["INPUT_COMMAND"]
+    args = os.environ["INPUT_ARGS"]
+
+    if install == "none":
+        # No install.
+        pass
+    elif install == "latest":
+        run_command("pip install dunamai")
+    else:
+        run_command("pip install dunamai=={}", install)
+
+    version = run_command("{} {}".format(command, args))
+    set_output("version", version)
+    print("Dynamic version: {}".format(version))
+
+    if env_var != "":
+        export_variable(env_var, version)
+
+
+if __name__ == "__main__":
+    try:
+        main()
+    except Exception as error:
+        set_failed(error)
+        exit(1)