Update makefile to generate requirements.

Author: nzlosh

Makefile

@@ -14,9 +14,8 @@ space_char +=
 comma := ,
 COMPONENT_PYTHONPATH = $(subst $(space_char),:,$(realpath $(COMPONENTS)))
 
-PYTHON_TARGET := 3.10
-
-REQUIREMENTS := test-requirements.txt requirements.txt
+PYTHON_VERSION := $(shell python3 --version | sed -r 's/.*([[0-9]+\.[0-9]+)\.[0-9]+.*/\1/g')
+REQUIREMENTS := test-requirements-$(PYTHON_VERSION).txt requirements.txt
 # Grab the version of pip from the Makefile in the st2 repository
 #
 # 1. Grab the st2 branch name from ST2_BRANCH
@@ -73,7 +72,7 @@ pylint: requirements .pylint
 	. $(VIRTUALENV_DIR)/bin/activate; pylint -E --rcfile=./lint-configs/python/.pylintrc packs/fixtures/actions/scripts/*/*.py || exit 1;
 	. $(VIRTUALENV_DIR)/bin/activate; pylint -E --rcfile=./lint-configs/python/.pylintrc packs/fixtures/sensors/*.py || exit 1;
 	. $(VIRTUALENV_DIR)/bin/activate; pylint -E --rcfile=./lint-configs/python/.pylintrc packs/asserts/actions/*.py || exit 1;
-	
+
 .PHONY: flake8
 flake8: requirements .flake8
 
@@ -140,3 +139,35 @@ $(VIRTUALENV_DIR)/bin/activate:
 	echo '  functions -e old_deactivate' >> $(VIRTUALENV_DIR)/bin/activate.fish
 	echo 'end' >> $(VIRTUALENV_DIR)/bin/activate.fish
 	touch $(VIRTUALENV_DIR)/bin/activate.fish
+
+.PHONY: piptools
+piptools: virtualenv
+	@echo
+	@echo "================== Install pip-tools ===================="
+	@echo
+	"$(VIRTUALENV_DIR)/bin/pip" install pip-tools
+
+.PHONY: generate_requirements
+generate_requirements: piptools
+	@echo
+	@echo "================== Generate requirements file ===================="
+	@echo
+	"$(VIRTUALENV_DIR)/bin/pip-compile" --output-file=$(ROOT_DIR)/test-requirements-$(PYTHON_VERSION).txt $(ROOT_DIR)/test-requirements.in
+
+.PHONY: check_generated_files
+check_generated_files:
+	# Verify that all the files that are automatically generated have been regenerated and committed.
+	@echo "==================== Check requirements file ===================="
+	make generate_requirements
+	export NEED_COMMIT=0; \
+	export REQ_FILE="$(ROOT_DIR)/test-requirements-$(PYTHON_VERSION).txt"
+	export FILE=$$(git status -s "$$REQ_FILE"); \
+	if grep -E " M $$REQ_FILE" <<<$$FILE ; then \
+		echo "$$REQ_FILE hasn't been re-generated and committed. Please run \"make generate_requirements\" then include and commit the generated file."; \
+		export NEED_COMMIT=1; \
+		git diff "$$REQ_FILE" | cat; \
+	elif grep -E "\?\? $$REQ_FILE" <<<$$FILE ; then \
+		echo "$$REQ_FILE does not appear to be under git control!?  Please add it to git or remove it from the directory."; \
+	fi; \
+	test $$NEED_COMMIT -eq 1 && exit 2 || true
+	@echo "All automatically generated files are up to date."

README.md

@@ -36,3 +36,9 @@ For example:
 git subtree pull --prefix test_helpers/bats-assert https://github.com/ztombol/bats-assert.git master --squash
 git subtree pull --prefix test_helpers/bats-support https://github.com/ztombol/bats-support.git master --squash
 ```
+
+## Supported Python versions
+
+StackStorm supports mulitple versions of python across numerous GNU/Linux distributions.  To define python dependencies in a
+reproducible fashion, the `pip-compile` tool is used to resolve dependencies from the `requirements.in` file.  The requirements
+are kept up to date with the `st2` repository and should be regenerated when requirements are updated.