Some Docker-refinements

- use multi-stage build: build the binary in a `alpine:golang3.11` image
  but use `busybox:stable` for the run time image and just pick the
  build artifacts ... this reduces the image size from 384mb -> 12.4mb
- build with CGO_ENABLED=0 to avoid dependency to glibc: this makes it
  more compatible with different types of linux images
- add EXPOSE statement to Dockerfile
- add `USER=nobody` statement to avoid running as root within the
  container
- remove `-it` option from README: this is only needed if you want to
  interactively use the container
- use 0.0.0.0 as the default listing host ... otherwise requests from
  other hosts will not be responded to

However: `sendmail` is missing from the container and therefore this
will not run correctly. As I don't know whether it usually runs with
sendmail I stopped at this point -- happy to support again

Dockerfile

@@ -1,7 +1,16 @@
-FROM golang:alpine3.11
+FROM golang:alpine3.11 as base
 
 WORKDIR /app
 COPY . /app
 
+ENV CGO_ENABLED=0
 RUN go build -o bin/naveed
-CMD ["/app/bin/naveed"]
+
+FROM busybox
+
+COPY --from=base /app/bin/naveed /usr/bin/naveed
+COPY --from=base /app/naveed.ini /
+
+EXPOSE 8465/tcp
+USER nobody
+CMD ["/usr/bin/naveed"]

README.md

@@ -65,8 +65,8 @@ NB:
 
 * run:
 
-        $ docker run -it --rm --name naveed -p8080:8465
-                -v "$(pwd)/config:/app/config" \
+        $ docker run --rm --name naveed -p8080:8465
+                -v "$(pwd)/config:/" \
                 -e NAVEED_USERS_URL=… \
                 -e NAVEED_USERS_USERNAME=… \
                 -e NAVEED_USERS_PASSWORD=… \

naveed.ini

@@ -2,7 +2,7 @@
 # * relative paths originate from the application's working directory
 # * changes require restarting the server
 
-host = "localhost"
+host = "0.0.0.0"
 port = 8465
 path-prefix = "/naveed"
 external-root = "https://example.org/naveed/"