update container entrypoint to restart when config file changes

Dockerfile

@@ -1,12 +1,18 @@
-FROM golang:1.13
+FROM golang:1.13-alpine
 
 COPY . /work
+
 WORKDIR /work
+
 RUN CGO_ENABLED=0 GOOS=linux go build -a -installsuffix cgo -o prometheus-nginxlog-exporter
 
-FROM scratch
+FROM alpine
+
+RUN apk add --no-cache -X http://dl-cdn.alpinelinux.org/alpine/edge/testing watchexec
 
 COPY --from=0 /work/prometheus-nginxlog-exporter /prometheus-nginxlog-exporter
+ADD entrypoint.sh /entrypoint.sh
 
 EXPOSE 4040
-ENTRYPOINT ["/prometheus-nginxlog-exporter"]
+
+ENTRYPOINT ["/entrypoint.sh"]

entrypoint.sh

@@ -0,0 +1,3 @@
+#!/bin/sh
+
+watchexec  -v -w "/etc/prometheus-nginxlog-exporter/" -n -r /prometheus-nginxlog-exporter