Makefile: add some convenenience functions

The on-prem version of this repo depends on the `cockpit` project. Some
of the files from the `cockpit` repo are needed to build and run this
project. These files are saved into the `pkg/lib` directory, this commit
adds some convenience scripts to the Makefile to do this.

.gitignore

@@ -36,3 +36,6 @@ cockpit/public/main*
 
 # Sentry Config File
 .sentryclirc
+
+# cockpit lib dir
+pkg/lib

Makefile

@@ -1,17 +1,52 @@
-INSTALL_DIR := ~/.local/share/cockpit/image-builder-frontend
+PACKAGE_NAME = image-builder-frontend
+INSTALL_DIR = /share/cockpit/$(PACKAGE_NAME)
 
-cockpit/all: devel-uninstall devel-install build
+# TODO: figure out a strategy for keeping this updated
+COCKPIT_REPO_COMMIT = b0e82161b4afcb9f0a6fddd8ff94380e983b2238
+COCKPIT_REPO_URL = https://github.com/cockpit-project/cockpit.git
+COCKPIT_REPO_TREE = '$(strip $(COCKPIT_REPO_COMMIT))^{tree}'
 
-devel-install:
-	mkdir -p ~/.local/share/cockpit
-	ln -s $(shell pwd)/cockpit/public $(INSTALL_DIR)
+# checkout common files from Cockpit repository required to build this project;
+# this has no API stability guarantee, so check out a stable tag when you start
+# a new project, use the latest release, and update it from time to time
+COCKPIT_REPO_FILES = \
+	pkg/lib \
+	$(NULL)
 
-build:
+help:
+	@cat Makefile
+
+#
+# Cockpit related targets
+#
+
+.PHONY: cockpit/clean
+cockpit/clean:
+	rm -f cockpit/public/*.css
+	rm -f cockpit/public/*.js
+
+.PHONY: cockpit/devel-uninstall
+cockpit/devel-uninstall: PREFIX=~/.local
+cockpit/devel-uninstall:
+	rm -rf $(PREFIX)$(INSTALL_DIR)
+
+.PHONY: cockpit/devel-install
+cockpit/devel-install: PREFIX=~/.local
+cockpit/devel-install:
+	PREFIX="~/.local"
+	mkdir -p $(PREFIX)$(INSTALL_DIR)
+	ln -s $(shell pwd)/cockpit/public $(PREFIX)$(INSTALL_DIR)
+
+.PHONY: cockpit/download
+cockpit/download: Makefile
+	@git rev-list --quiet --objects $(COCKPIT_REPO_TREE) -- 2>/dev/null || \
+	    git fetch --no-tags --no-write-fetch-head --depth=1 $(COCKPIT_REPO_URL) $(COCKPIT_REPO_COMMIT)
+	git archive $(COCKPIT_REPO_TREE) -- $(COCKPIT_REPO_FILES) | tar x
+
+.PHONY: cockpit/build
+cockpit/build: cockpit/download
+	npm ci
 	npm run build:cockpit
 
-devel-uninstall:
-	rm -rf $(INSTALL_DIR)
-	rm cockpit/public/*.css
-	rm cockpit/public/*.js
-
-.PHONY: cockpit/all devel-install build devel-uninstall
+.PHONY: cockpit/devel
+cockpit/devel: cockpit/devel-uninstall cockpit/build cockpit/devel-install