mgmt/modules/prometheus/main.mcl

import "deploy"
import "fmt"
import "golang"
import "golang/strings" as golang_strings
import "golang/strconv" as golang_strconv
import "local"
import "os"
import "strings"

class server() {
	pkg "golang-github-prometheus" { # fedora
		state => "installed",

		Before => File["/etc/prometheus/"],
		Before => Svc["prometheus"],
	}

	file "/etc/prometheus/" {
		state => $const.res.file.state.exists,
		recurse => true,
		purge => true,
		owner => "prometheus",
		group => "root",
		mode => "u=rwx,g=rx,o=", # dir
	}

	file "${vardir}prometheus.yml.header" {
		state => $const.res.file.state.exists,
		content => golang.template(deploy.readfile("/files/prometheus.yml.tmpl")),
		owner => "root",
		group => "root",
		mode => "u=rw,go=",
	}

	file "/etc/prometheus/prometheus.yml" {
		state => $const.res.file.state.exists,
		fragments => [
			"${vardir}prometheus.yml.header", # also pull this one file
			"${vardir}jobs.d/", # pull from this dir
		],
		owner => "prometheus",
		group => "root",
		mode => "u=rw,g=r,o=",

		Notify => Svc["prometheus"],
	}

	svc "prometheus" {
		state => "running",
		startup => "enabled",
	}

	# permissions are important for this dir, make sure they're correct
	file "/var/lib/prometheus/" {
		state => $const.res.file.state.exists,
		owner => "prometheus",
		group => "root",
		mode => "u=rwx,g=rx,o=", # dir
	}

	$vardir = local.vardir("prometheus/")

	# Add the default exporter.
	include job("node", struct{
		#host => "localhost",
		#port => 9100,
	})
}

class server:job_base() {
	file "${vardir}jobs.d/" {
		state => $const.res.file.state.exists,
		recurse => true,
		purge => true,
		owner => "root",
		group => "root",
		mode => "u=rwx,go=", # dir
	}
}

class server:job($name, $st) {
	# XXX: document why this is named job_base instead of base:job_base or
	# change the compiler to use the second version?
	include job_base

	$host = $st->host || "localhost"
	$port = $st->port || 9100
	$comment = $st->comment || ""

	$tmpl = struct{
		name => "${name}",
		host => "${host}",
		port => fmt.printf("%d", $port),
		comment => "${comment}",
	}

	file "${vardir}jobs.d/${name}.job" {
		state => $const.res.file.state.exists,
		content => golang.template(deploy.readfile("/files/prometheus.yml.frag.tmpl"), $tmpl),
		owner => "root",
		group => "root",
		mode => "u=rw,go=",
	}
}

class exporter() {
	if os.is_family_redhat() { # we only use fedora atm
		pkg "node-exporter" { # fedora
			state => "installed",

			#Before => File["/etc/default/prometheus-node-exporter"],
			Before => Svc["prometheus-node-exporter"],
		}
	}
	if os.is_family_debian() {
		pkg "prometheus-node-exporter" { # debian
			state => "installed",

			#Before => File["/etc/default/prometheus-node-exporter"],
			Before => Svc["prometheus-node-exporter"],
		}
	}

	# TODO: manage /etc/default/prometheus-node-exporter

	svc "prometheus-node-exporter" {
		state => "running",
		startup => "enabled",
	}
}

class postgresql_base() {

	#if os.is_family_redhat() {
	#	pkg [
	#		"", # XXX: No obvious Fedora package available
	#	] {
	#		state => "installed",
	#	}
	#}
	if os.is_family_debian() {
		pkg [
			"prometheus-postgres-exporter",
		] {
			state => "installed",

			Before => Svc["prometheus-postgres-exporter"],
		}
	}

	# systemd service template file to allow for multiple of these
	file "/etc/systemd/system/prometheus-postgres-exporter@.service" {
		state => $const.res.file.state.exists,
		content => deploy.readfile("/files/prometheus-postgres-exporter.service"),
		owner => "root",
		group => "root",
		mode => "u=rw,go=r",

#		Depend => Pkg["prometheus-postgres-exporter"],
#		Before => Svc["prometheus-postgres-exporter"],
	}

}

# We call this postgresql instead of postgres.
# XXX: you may not wish to have spaces in your passwords
class postgresql($config) {

	include postgresql_base

	$host = $config->host || "127.0.0.1"
	$port = $config->port || 5432
	$user = $config->user || "prometheus"
	$pass = $config->pass || ""
	$dbname = $config->dbname || ""
	$sslmode = $config->sslmode || false
	$listen_port = $config->listen_port || 9187

	panic($port <= 0)

	$h = if $host == "" {
		""
	} else {
		"host=${host}"
	}
	$o = fmt.printf("port=%d", $port)
	$u = if $user == "" {
		""
	} else {
		"user=${user}"
	}
	$p = if $pass == "" {
		""
	} else {
		"password=${pass}"
	}
	$d = if $dbname == "" {
		""
	} else {
		"dbname=${dbname}"
	}
	$m = if $sslmode {
		""
	} else {
		"sslmode=disable"
	}

	$l = [$h, $o, $u, $p, $d, $m,] # filter out empties first (IT'S REQUIRED)
	$dsn = strings.join_nonempty($l, " ") # trailing spaces break this exporter

	$str_port = golang_strconv.itoa($port)
	$str_listen_port = golang_strconv.itoa($listen_port)

	$args = "--web.listen-address=:${str_listen_port}"

	$tmpl = struct{
		# DATA_SOURCE_NAME='postgresql://login:password@hostname:port/' # untested?
		# DATA_SOURCE_NAME='user=prometheus host=/run/postgresql dbname=postgres' # untested?
		# DATA_SOURCE_NAME='host=127.0.0.1 port=5432 user=prometheus password=hunter2 dbname=postgres sslmode=disable' # works
		port => $port,
		dsn => $dsn,
		args => $args,
	}

	file "/etc/default/prometheus-postgres-exporter-${str_port}" {
		state => $const.res.file.state.exists,
		content => golang.template(deploy.readfile("/files/prometheus-postgres-exporter.default.tmpl"), $tmpl),
		owner => "prometheus",
		group => "root",
		mode => "ug=rw,o=",

		Depend => Pkg["prometheus-postgres-exporter"],
		Before => Svc["prometheus-postgres-exporter@${str_port}"],
	}

	svc "prometheus-postgres-exporter@${str_port}" {
		state => "running",
		startup => "enabled",
	}

	$vardir = local.vardir("prometheus/")
	# there can only be one on each listen port!
	# if more than one of these is set on the same machine we'd error
	file "${vardir}postgresql-${str_listen_port}" {
		state => $const.res.file.state.exists,
		content => "${str_port}",
		owner => "root",
		group => "root",
		mode => "u=rw,go=",
	}
}