add simplfified ecr build/push script

scripts/ecr.mk

@@ -0,0 +1,67 @@
+# This file is based on binaries.mk and dockerhub.mk. It's simplified to
+# build just the platform we need, and push to ECR.
+#
+# This file assumes you already have a valid ECR login, see Amazon's
+# instructions: https://docs.aws.amazon.com/AmazonECR/latest/userguide/getting-started-cli.html#cli-authenticate-registry
+#
+BINARY_NAME = mediamtx
+
+define DOCKERFILE_BINARIES
+FROM $(BASE_IMAGE) AS build-base
+RUN apk add --no-cache zip make git tar
+WORKDIR /s
+COPY go.mod go.sum ./
+RUN go mod download
+COPY . ./
+ARG VERSION
+ENV CGO_ENABLED 0
+RUN rm -rf tmp binaries
+RUN mkdir tmp binaries
+RUN cp mediamtx.yml LICENSE tmp/
+RUN go generate ./...
+
+FROM build-base AS build-linux-amd64
+RUN GOOS=linux GOARCH=amd64 go build -ldflags "-X github.com/bluenviron/mediamtx/internal/core.version=$$VERSION" -o tmp/$(BINARY_NAME)
+RUN tar -C tmp -czf binaries/$(BINARY_NAME)_$${VERSION}_linux_amd64.tar.gz --owner=0 --group=0 $(BINARY_NAME) mediamtx.yml LICENSE
+
+FROM $(BASE_IMAGE)
+COPY --from=build-linux-amd64 /s/binaries /s/binaries
+endef
+export DOCKERFILE_BINARIES
+
+ecr-binaries:
+	echo "$$DOCKERFILE_BINARIES" | DOCKER_BUILDKIT=1 docker build . -f - \
+	--build-arg VERSION=$$(git describe --tags) \
+	-t temp
+	docker run --rm -v $(PWD):/out \
+	temp sh -c "rm -rf /out/binaries && cp -r /s/binaries /out/"
+
+define DOCKERFILE_ECR
+FROM scratch
+ARG TARGETPLATFORM
+ADD tmp/binaries/$$TARGETPLATFORM.tar.gz /
+ENTRYPOINT [ "/mediamtx" ]
+endef
+export DOCKERFILE_ECR
+
+ecr-push:
+	$(eval VERSION := $(shell git describe --tags | tr -d v))
+
+	if [ -z "$(ECR_TAG)" ]; then \
+		echo "ECR_TAG is required"; \
+		exit 1; \
+	fi
+
+	rm -rf tmp
+	mkdir -p tmp tmp/binaries/linux/arm tmp/rpi_base/linux/arm
+
+	cp binaries/*linux_amd64.tar.gz tmp/binaries/linux/amd64.tar.gz
+
+	echo "$$DOCKERFILE_ECR" | docker buildx build . -f - \
+	--provenance=false \
+	--platform=linux/amd64 \
+	-t $(ECR_TAG) \
+	--push
+
+	docker buildx rm builder || true
+	rm -rf $$HOME/.docker/manifests/*