debian: add package building (#20)

This only builds on a debian system, because it uses the dpkg-helper
and other utils. But it builds! Multiarch is supported, you can easily
build a package for amd64, arm and arm64. The Makefile does this by
default.

Massively update the systemd file.

debian/Corefile

@@ -0,0 +1,9 @@
+# Default Corefile, see https://coredns.io for more information.
+
+# Answer every below the root, with the whoami plugin. Log all queries
+# and errors on standard output.
+. {
+    whoami  # coredns.io/plugins/whoami
+    log     # coredns.io/plugins/log
+    errors  # coredns.io/plugins/errors
+}

debian/changelog

@@ -0,0 +1,5 @@
+coredns (0-0) UNRELEASED; urgency=medium
+
+  * Package for Debian.
+
+ -- Miek Gieben <miek@coredns.io>  Sat, 11 Nov 2017 09:52:00 +0000

debian/compat

@@ -0,0 +1 @@
+10

debian/control

@@ -0,0 +1,8 @@
+Source: coredns
+Maintainer: Miek Gieben <miek@coredns.io>
+Build-Depends: debhelper (>= 9), ca-certificates, wget, dh-systemd
+
+Package: coredns
+Architecture: any
+Description: DNS server that chains plugins
+Depends: adduser

debian/coredns.service

@@ -0,0 +1,20 @@
+[Unit]
+Description=CoreDNS DNS server
+Documentation=https://coredns.io
+After=network.target
+
+[Service]
+PermissionsStartOnly=true
+LimitNOFILE=1048576
+LimitNPROC=512
+CapabilityBoundingSet=CAP_NET_BIND_SERVICE 
+AmbientCapabilities=CAP_NET_BIND_SERVICE 
+NoNewPrivileges=true 
+User=coredns
+WorkingDirectory=~
+ExecStart=/usr/bin/coredns -conf=/etc/coredns/Corefile
+ExecReload=/bin/kill -SIGUSR1 $MAINPID
+Restart=on-failure
+
+[Install]
+WantedBy=multi-user.target

debian/rules

@@ -0,0 +1,29 @@
+#!/usr/bin/make -f
+
+VERSION := 0.9.10
+
+DEB_HOST_ARCH   := $(DEB_TARGET_ARCH)
+DISTRIBUTION    := $(shell lsb_release -sr)
+PACKAGEVERSION  := $(VERSION)-0~$(DISTRIBUTION)0
+TARBALL         := coredns_$(VERSION)_linux_$(DEB_TARGET_ARCH).tgz
+URL             := https://github.com/coredns/coredns/releases/download/v$(VERSION)/$(TARBALL)
+
+%:
+	dh_clean
+	dh $@ --with systemd
+
+override_dh_strip:
+	# don't perform dh_strip
+	echo dh_strip
+
+override_dh_auto_clean:
+override_dh_auto_test:
+override_dh_auto_build:
+override_dh_auto_install:
+	wget -N --progress=dot:mega $(URL)
+	mkdir -p debian/coredns/usr/bin debian/coredns/etc/coredns
+	tar -xf $(TARBALL) -C debian/coredns/usr/bin
+	cp debian/Corefile debian/coredns/etc/coredns/Corefile
+
+override_dh_gencontrol:
+	dh_gencontrol -- -v$(PACKAGEVERSION)