Some build improvements

- All targets in the `Makefile` now work
- Upated the documentation on getting started

Author: cread

.gitignore

@@ -1,2 +1,3 @@
 bin/
+go/
 *.snap

DEVELOPMENT.md

@@ -1,8 +1,10 @@
+# Development
+
 Setup the development environment on a node with access to the Slurm user
 command-line interface, in particular with the `sinfo`, `squeue`, and `sdiag`
 commands.
 
-### Install Go from source
+## Install Go from source
 
 ```bash
 export VERSION=1.15 OS=linux ARCH=amd64
@@ -13,51 +15,40 @@ export PATH=$PWD/go/bin:$PATH
 
 _Alternatively install Go using the packaging system of your Linux distribution._
 
-Use Git to clone the source code of the exporter, and download all Go dependency
-modules:
+## Clone this repository and build
+
+Use Git to clone the source code of the exporter, run all the tests and build the binary:
 
 ```bash
 # clone the source code
 git clone https://github.com/vpenso/prometheus-slurm-exporter.git
 cd prometheus-slurm-exporter
-# download dependencies
-export GOPATH=$PWD/go/modules
-go mod download
-```
-
-### Build
-
-Build the exporter:
-
-```bash
-go build -o bin/prometheus-slurm-exporter {main,accounts,cpus,gpus,partitions,nodes,queue,scheduler,sshare,users}.go
+make
 ```
 
-Run all tests included in `_test.go` files:
+To just run the tests:
 
 ```bash
-go test -v *.go
+make test
 ```
 
 Start the exporter (foreground), and query all metrics:
 
 ```bash
-bin/prometheus-slurm-exporter
+./bin/prometheus-slurm-exporter
 ```
 
 If you wish to run the exporter on a different port, or the default port (8080) is already in use, run with the following argument:
 
 ```bash
-bin/prometheus-slurm-exporter --listen-address="0.0.0.0:<port>"
+./bin/prometheus-slurm-exporter --listen-address="0.0.0.0:<port>"
 ...
 
 # query all metrics (default port)
 curl http://localhost:8080/metrics
 ```
 
-### Development
-
-References:
+## References
 
 * [GOlang Package Documentation](https://godoc.org/github.com/prometheus/client_golang/prometheus)
 * [Metric Types](https://prometheus.io/docs/concepts/metric_types/)

Makefile

@@ -1,20 +1,28 @@
 PROJECT_NAME = prometheus-slurm-exporter
-ifndef GOPATH
-	GOPATH=$(shell pwd):/usr/share/gocode
-endif
-GOFILES=accounts.go cpus.go gpus.go main.go nodes.go partitions.go queue.go scheduler.go sshare.go users.go
-GOBIN=bin/$(PROJECT_NAME)
+SHELL := $(shell which bash) -eu -o pipefail
 
-build:
-	mkdir -p $(shell pwd)/bin
-	@echo "Build $(GOFILES) to $(GOBIN)"
-	@GOPATH=$(GOPATH) go build -o $(GOBIN) $(GOFILES)
+GOPATH := $(shell pwd)/go/modules
+GOBIN := bin/$(PROJECT_NAME)
+GOFILES := $(shell ls *.go)
 
-test:
-	@GOPATH=$(GOPATH) go test -v *.go
+.PHONY: build
+build: test $(GOBIN)
 
-run:
-	@GOPATH=$(GOPATH) go run $(GOFILES)
+$(GOBIN): go/modules/pkg/mod $(GOFILES)
+	mkdir -p bin
+	@echo "Building $(GOBIN)"
+	go build -v -o $(GOBIN)
+
+go/modules/pkg/mod: go.mod
+	go mod download
+
+.PHONY: test
+test: go/modules/pkg/mod $(GOFILES)
+	go test -v
+
+run: $(GOBIN)
+	$(GOBIN)
 
 clean:
-	if [ -f ${GOBIN} ] ; then rm -f ${GOBIN} ; fi
+	go clean -modcache
+	rm -fr bin/ go/