Read version from file

Dockerfile

@@ -25,6 +25,7 @@ COPY lib lib
 COPY priv/repo/migrations priv/repo/migrations
 COPY priv/gettext priv/gettext
 COPY grafana/dashboards grafana/dashboards
+COPY VERSION VERSION
 
 RUN mkdir -p /opt/built && \
     mix "do" compile, release --path /opt/built

Makefile

@@ -1,17 +1,19 @@
-.PHONY: help grafana teslamate
+.PHONY: help vsn grafana teslamate
 
 APP_NAME ?= `grep 'app:' mix.exs | sed -e 's/\[//g' -e 's/ //g' -e 's/app://' -e 's/[:,]//g'`
-APP_VSN ?= `grep 'version:' mix.exs | cut -d '"' -f2`
+APP_VSN ?= `cat VERSION`
 BUILD ?= `git rev-parse --short HEAD`
 
-help:
-	@echo "$(APP_NAME):$(APP_VSN)-$(BUILD)"
+help: vsn
 	@perl -nle'print $& if m{^[a-zA-Z_-]+:.*?## .*$$}' $(MAKEFILE_LIST) | sort | awk 'BEGIN {FS = ":.*?## "}; {printf "\033[36m%-30s\033[0m %s\n", $$1, $$2}'
 
-teslamate: ## Build teslamate Docker image
+vsn:
+	@echo "$(APP_NAME):$(APP_VSN)-$(BUILD)"
+
+teslamate: vsn ## Build teslamate Docker image
 	@docker build --pull \
 			-t $(APP_NAME):$(APP_VSN)-$(BUILD) \
 			-t $(APP_NAME) .
 
-grafana: ## Build  teslamate-grafana Docker image
+grafana: vsn ## Build  teslamate-grafana Docker image
 	@cd grafana && docker build --pull -t teslamate-grafana .

VERSION

@@ -0,0 +1 @@
+1.21.0-dev

mix.exs

@@ -4,7 +4,7 @@ defmodule TeslaMate.MixProject do
   def project do
     [
       app: :teslamate,
-      version: "1.20.0",
+      version: version(),
       elixir: "~> 1.10",
       elixirc_paths: elixirc_paths(Mix.env()),
       compilers: [:phoenix, :gettext] ++ Mix.compilers(),
@@ -81,4 +81,11 @@ defmodule TeslaMate.MixProject do
       ]
     ]
   end
+
+  defp version do
+    case File.read("VERSION") do
+      {:ok, version} -> String.trim(version)
+      {:error, _reason} -> "0.0.0"
+    end
+  end
 end