Add Dockerfile for building docker image

.dockerignore

@@ -0,0 +1,2 @@
+Dockerfile
+.git/

Dockerfile

@@ -0,0 +1,32 @@
+# Using Debian bullseye for building regular image.
+# Using scratch image for minimal image size.
+# The final image has:
+#
+# - Timezone info file.
+# - CA certs file.
+# - /etc/{passwd,group} file.
+# - Non-cgo ctrld binary.
+#
+# CI_COMMIT_TAG is used to set the version of ctrld binary.
+FROM golang:bullseye as base
+
+WORKDIR /app
+
+RUN apt-get update && apt-get install -y upx-ucl
+
+COPY . .
+
+ARG tag=master
+ENV CI_COMMIT_TAG=$tag
+RUN CGO_ENABLED=0 ./scripts/build.sh linux/amd64
+
+FROM scratch
+
+COPY --from=base /usr/share/zoneinfo /usr/share/zoneinfo
+COPY --from=base /etc/ssl/certs/ca-certificates.crt /etc/ssl/certs/
+COPY --from=base /etc/passwd /etc/passwd
+COPY --from=base /etc/group /etc/group
+
+COPY --from=base /app/ctrld-linux-amd64-nocgo ctrld
+
+ENTRYPOINT ["./ctrld", "run"]

README.md

@@ -67,6 +67,13 @@ or
 $ go install github.com/Control-D-Inc/ctrld/cmd/ctrld@latest
 ```
 
+## Docker
+
+```
+$ docker build -t controld/ctrld .
+$ docker run -d --name=ctrld -p 53:53/tcp -p 53:53/udp controld/ctrld --cd=p2 -vv
+```
+
 
 # Usage
 The cli is self documenting, so free free to run `--help` on any sub-command to get specific usages.