Resolver: New image.

Migrated from https://git.shore.co.il/nimrod/resolver.

.gitlab-ci.yml

@@ -244,3 +244,19 @@ push-workbench:
   needs:
     - job: build-workbench
       artifacts: true
+
+# resolver image:
+
+build-resolver:
+  extends: .container-build
+  variables:
+    CONTEXT: resolver
+
+push-resolver:
+  extends: .container-push
+  variables:
+    CONTEXT: resolver
+    IMAGE: resolver
+  needs:
+    - job: build-resolver
+      artifacts: true

resolver/.dockerignore

+*
+!entrypoint

resolver/Dockerfile

+FROM alpine:3.13
+# hadolint ignore=DL3018
+RUN echo '@testing http://dl-cdn.alpinelinux.org/alpine/edge/testing' >> /etc/apk/repositories && \
+    echo '@community http://dl-cdn.alpinelinux.org/alpine/edge/community' >> /etc/apk/repositories && \
+    apk add --update --no-cache \
+        bash \
+        dma@testing \
+        gosu@testing \
+        iproute2 \
+        knot-resolver@community \
+        knot-utils \
+        mailx \
+        mtr \
+    && \
+    ln -s /usr/bin/kdig /usr/local/bin/dig && \
+    ln -s /usr/bin/khost /usr/local/bin/host
+COPY entrypoint /usr/local/sbin/entrypoint
+WORKDIR /
+ENTRYPOINT [ "entrypoint" ]
+CMD [ "bash", "--login" ]

resolver/README.md

+# Resolver
+
+[![pipeline status](https://git.shore.co.il/nimrod/resolver/badges/master/pipeline.svg)](https://git.shore.co.il/nimrod/resolver/-/commits/master)
+
+Testing DNS with a clean cache resolver. More info at
+https://www.shore.co.il/blog/resolver/.
+
+## Usage
+
+```
+docker run --rm -it registry.shore.co.il/resolver
+```
+
+## License
+
+This software is licensed under the MIT license (see `LICENSE.txt`).
+
+## Author Information
+
+Nimrod Adar, [contact me](mailto:nimrod@shore.co.il) or visit my
+[website](https://www.shore.co.il/). Patches are welcome via
+[`git send-email`](http://git-scm.com/book/en/v2/Git-Commands-Email). The repository
+is located at: <https://git.shore.co.il/explore/>.

resolver/entrypoint

+#!/bin/sh
+set -eux
+kresd --addr '127.0.0.1' --noninteractive &
+echo 'nameserver 127.0.0.1' > /etc/resolv.conf
+# shellcheck disable=SC2294
+eval exec gosu nobody:nobody "$@"