Add make builder and make build-docker

Makefile

@@ -1,5 +1,12 @@
 GOPATH=$(shell cd ../../../.. && pwd)
 
+VERSION=$(shell git describe --long --tags --dirty --always)
+
+# Apply -dirty version suffix if there are staged or unstaged changes in ./builder
+BUILDER_DIRTY=$(shell git diff-files --quiet -- "builder" && git diff-index --quiet --cached HEAD -- "builder" || echo "-dirty")
+# Version builder by short commit sha of the builder dir, not the last probe version tag
+BUILDER_VERSION=$(shell git rev-list -1 HEAD -- "builder" | cut -c1-7)${BUILDER_DIRTY}
+
 default: all
 
 all: restoredeps test build
@@ -46,3 +53,12 @@ clean:
 
 env:
 	@godep go env
+
+.PHONY: builder
+builder:
+	@echo "--> Building builder: karlkfi/probe-builder:${BUILDER_VERSION}"
+	@docker build -t karlkfi/probe-builder:${BUILDER_VERSION} ./builder
+
+build-docker:
+	@echo "--> Building probe (in karlkfi/probe-builder:${BUILDER_VERSION})"
+	@docker run -v "$(shell pwd):/go/src/github.com/karlkfi/probe" karlkfi/probe-builder:${BUILDER_VERSION}

README.md

@@ -47,6 +47,27 @@ probe -t 1s https://example.com/
 The error description will be printed to STDERR.
 
 
+### Building
+
+Build locally:
+
+```
+make
+```
+
+Build in docker:
+
+```
+make build-docker
+```
+
+Build docker builder:
+
+```
+make builder
+```
+
+
 ### TODO
 
 1. Add SSL certificate validation options (currently ignores cert validity).