Add GOMAXPROCS support when building

Right now when we build the container (make docker-build) or the
controller (make build) the go compiler will try to use all the CPUs on
the machine.

This can become problematic in some systems that may suffer starvation
(eg: audio problems), so we add support for the `GOMAXPROCS` env var to
be passed to those 2 make targets.

Author: Akrog

Dockerfile

@@ -2,6 +2,7 @@
 FROM golang:1.24 AS builder
 ARG TARGETOS
 ARG TARGETARCH
+ARG GOMAXPROCS
 
 WORKDIR /workspace
 # Copy the Go Modules manifests
@@ -21,7 +22,7 @@ COPY internal/controller/ internal/controller/
 # was called. For example, if we call make docker-build in a local env which has the Apple Silicon M1 SO
 # the docker BUILDPLATFORM arg will be linux/arm64 when for Apple x86 it will be linux/amd64. Therefore,
 # by leaving it empty we can ensure that the container and binary shipped on it will have the same platform.
-RUN CGO_ENABLED=0 GOOS=${TARGETOS:-linux} GOARCH=${TARGETARCH} go build -a -o manager cmd/main.go
+RUN GOMAXPROCS=${GOMAXPROCS} CGO_ENABLED=0 GOOS=${TARGETOS:-linux} GOARCH=${TARGETARCH} go build -a -o manager cmd/main.go
 
 # Use distroless as minimal base image to package the manager binary
 # Refer to https://github.com/GoogleContainerTools/distroless for more details

Makefile

@@ -146,7 +146,7 @@ lint-fix: golangci-lint ## Run golangci-lint linter and perform fixes
 
 .PHONY: build
 build: manifests generate fmt vet ## Build manager binary.
-	go build -o bin/manager cmd/main.go
+	GOMAXPROCS=$(GOMAXPROCS) go build -o bin/manager cmd/main.go
 
 .PHONY: run
 run: manifests generate fmt vet ## Run a controller from your host.
@@ -157,7 +157,7 @@ run: manifests generate fmt vet ## Run a controller from your host.
 # More info: https://docs.docker.com/develop/develop-images/build_enhancements/
 .PHONY: docker-build
 docker-build: ## Build docker image with the manager.
-	$(CONTAINER_TOOL) build -t ${IMG} .
+	$(CONTAINER_TOOL) build --build-arg GOMAXPROCS=$(GOMAXPROCS) -t ${IMG} .
 
 .PHONY: docker-push
 docker-push: ## Push docker image with the manager.