create nutcracker exporter for prometheus (#835)

app-metrics/twemproxy_exporter/files/nutcracker_exporter.confd

@@ -0,0 +1,2 @@
+# arguments for ceph exporter
+command_args="-web.listen-address 0.0.0.0:9012 -twemproxy.stats-address localhost:12"

app-metrics/twemproxy_exporter/files/nutcracker_exporter.initd

@@ -0,0 +1,16 @@
+#!/sbin/openrc-run
+# Copyright 2016-2017 Gentoo Foundation
+# Distributed under the terms of the GNU General Public License v2
+
+description="Nutcracker metrics exporter"
+pidfile=${pidfile:-"/run/${RC_SVCNAME}.pid"}
+user=${user:-nobody}
+group=${group:-nobody}
+
+command="/usr/bin/nutcracker_exporter"
+command_background="true"
+start_stop_daemon_args="--user ${user} --group ${group}"
+
+depend() {
+	after net
+}

app-metrics/twemproxy_exporter/files/nutcracker_socket_exporter.confd

@@ -0,0 +1,2 @@
+# arguments for ceph exporter
+command_args="-web.listen-address 0.0.0.0:9146 -twemproxy.stats-address localhost:146"

app-metrics/twemproxy_exporter/files/nutcracker_socket_exporter.initd

@@ -0,0 +1,16 @@
+#!/sbin/openrc-run
+# Copyright 2016-2017 Gentoo Foundation
+# Distributed under the terms of the GNU General Public License v2
+
+description="Nutcracker metrics exporter"
+pidfile=${pidfile:-"/run/${RC_SVCNAME}.pid"}
+user=${user:-nobody}
+group=${group:-nobody}
+
+command="/usr/bin/nutcracker_exporter"
+command_background="true"
+start_stop_daemon_args="--user ${user} --group ${group}"
+
+depend() {
+	after net
+}

app-metrics/twemproxy_exporter/metadata.xml

@@ -0,0 +1,8 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE pkgmetadata SYSTEM "https://www.gentoo.org/dtd/metadata.dtd">
+<pkgmetadata>
+<maintainer type="person">
+<email>[email protected]</email>
+<name>Sherif Labib</name>
+</maintainer>
+</pkgmetadata>

app-metrics/twemproxy_exporter/twemproxy_exporter-0.1.0.ebuild

@@ -0,0 +1,27 @@
+# Copyright 1999-2023 Gentoo Authors
+# Distributed under the terms of the GNU General Public License v2
+
+EAPI=7
+inherit go-module
+inherit git-r3
+
+DESCRIPTION="Prometheus exporter that scrapes metrics from a nutcracker"
+HOMEPAGE="https://github.com/stuartnelson3/twemproxy_exporter"
+EGIT_REPO_URI="https://github.com/stuartnelson3/twemproxy_exporter.git"
+LICENSE="Apache-2.0"
+SLOT="0"
+KEYWORDS="~amd64"
+
+DEPEND="dev-lang/go"
+
+src_compile() {
+		go build -o nutcracker_exporter || die
+}
+
+src_install() {
+		dobin nutcracker_exporter
+		newconfd "${FILESDIR}"/nutcracker_exporter.confd nutcracker_exporter
+		newinitd "${FILESDIR}"/nutcracker_exporter.initd nutcracker_exporter
+		newconfd "${FILESDIR}"/nutcracker_socket_exporter.confd nutcracker_socket_exporter
+		newinitd "${FILESDIR}"/nutcracker_socket_exporter.initd nutcracker_socket_exporter
+}