__prometheus_server: switch to packages; assume prometheus 2.x

cdist/conf/type/__prometheus_server/man.rst

@@ -10,18 +10,12 @@ DESCRIPTION
 -----------
 Install and configure Prometheus (https://prometheus.io/).
 
-This type creates a daemontools-compatible service directory under /service/prometheus.
-Daemontools (or something compatible) must be installed (in particular, the command `svc` must be executable).
-
+Note that due to significant differences between Prometheus 1.x and 2.x, only 2.x is supported.
 
 REQUIRED PARAMETERS
 -------------------
 config
    Prometheus configuration file. It will be saved as /etc/prometheus/prometheus.yml on the target.
-listen-address
-   Passed as web.listen-address.
-alertmanager-url
-   Passed as alertmanager.url
 
 
 OPTIONAL PARAMETERS
@@ -32,8 +26,6 @@ rule-files
    Path to rule files. They will be installed under /etc/prometheus/<filename>. You need to include `rule_files: [/etc/prometheus/<your-pattern>]` in the config file if you use this.
 storage-path
    Where to put data. Default: /data/prometheus. (Directory will be created if needed.)
-target-heap-size
-   Passed as storage.local.target-heap-size. Default: 1/2 of RAM.
 
 
 BOOLEAN PARAMETERS
@@ -49,22 +41,16 @@ EXAMPLES
     PROMPORT=9090
     ALERTPORT=9093
 
-    __daemontools
-    __golang_from_vendor --version 1.8.1  # required for prometheus and many exporters
-
-    require="__daemontools __golang_from_vendor" __prometheus_server \
-        --with-daemontools \
+    __prometheus_server \
         --config "$__manifest/files/prometheus.yml" \
         --retention-days 14 \
         --storage-path /data/prometheus \
-        --listen-address "[::]:$PROMPORT" \
-        --rule-files "$__manifest/files/*.rules" \
-        --alertmanager-url "http://monitoring1.node.consul:$ALERTPORT,http://monitoring2.node.consul:$ALERTPORT"
+        --rule-files "$__manifest/files/*.rules"
 
 
 SEE ALSO
 --------
-:strong:`cdist-type__prometheus_alertmanager`\ (7), :strong:`cdist-type__daemontools`\ (7),
+:strong:`cdist-type__prometheus_alertmanager`\ (7), :strong:`cdist-type__grafana_dashboard`\ (7),
 Prometheus documentation: https://prometheus.io/docs/introduction/overview/
 
 AUTHORS
@@ -73,7 +59,7 @@ Kamila Součková <kamila--@--ksp.sk>
 
 COPYING
 -------
-Copyright \(C) 2017 Kamila Součková. You can redistribute it
+Copyright \(C) 2018 Kamila Součková. You can redistribute it
 and/or modify it under the terms of the GNU General Public License as
 published by the Free Software Foundation, either version 3 of the
 License, or (at your option) any later version.

cdist/conf/type/__prometheus_server/manifest

@@ -1,52 +1,69 @@
 #!/bin/sh -e
 
-GOBIN=/opt/gocode/bin  # where to find go binaries
+##### HARD-CODED CONFIG #####################################################
+
 CONF_DIR=/etc/prometheus
 CONF=$CONF_DIR/prometheus.yml
-LOGLEVEL=info
+
+##### GET SETTINGS ##########################################################
 
 config="$(cat "$__object/parameter/config")"
 retention_days="$(cat "$__object/parameter/retention-days")"
 storage_path="$(cat "$__object/parameter/storage-path")"
-listen_address="$(cat "$__object/parameter/listen-address")"
-alertmanager_url="$(cat "$__object/parameter/alertmanager-url")"
-target_heap_size="$(cat "$__object/parameter/target-heap-size")"
 rule_files="$(cat "$__object/parameter/rule-files")"
 
 # explorer in kB => convert; by default we go with 1/2 RAM
 [ "$target_heap_size" = "auto" ] && target_heap_size=$(($(cat $__global/explorer/memory)*1024/2))
 
+##### INSTALL THE PACKAGE ###################################################
 
-FLAGS="config.file '$CONF'
-storage.local.path '$storage_path'
-storage.local.target-heap-size $(($target_heap_size))  # in bytes; should be 2/3 of available memory because it may be hungry
-storage.local.retention $(($retention_days*24))h  # golang doesn't have days :D
-web.listen-address '$listen_address'
-alertmanager.url '$alertmanager_url'
-log.level $LOGLEVEL"
+if [ -f "$__object/parameter/install-from-backports" ]; then
+	os=$(cat "$__global/explorer/os")
+	lsb_codename=$(cat "$__global/explorer/lsb_codename")
 
-REAL_FLAGS="$(echo "$FLAGS" | sed -nE 's/^([^#]+).*/ --\1 \\/p')"
+	case $os in
+		devuan)
+			if [ -z "$lsb_codename" ]; then
+				echo "Command `lsb_release` not functional -- is package `lsb-release` installed?" >&2
+				exit 1
+			fi
+			[ "$lsb_codename" = "n/a" ] && lsb_codename='ascii'  # TODO this is a devuan bug that should be fixed soon => remove when no longer needed
+			__apt_source backports --uri http://auto.mirror.devuan.org/merged --distribution $lsb_codename-backports --component main
+			require="$require __apt_source/backports" __package_apt prometheus --target-release $lsb_codename-backports
+		;;
+		*)
+			echo "--install-from-backports is only supported on Devuan -- ignoring" >&2
+			echo "send a pull request if you require it" >&2
+		;;
+	esac
+else
+	__package prometheus
+fi
 
-__go_get github.com/prometheus/prometheus/cmd/...
+##### PREPARE PATHS AND SUCH ################################################
 
-__user prometheus --system
-require="__user/prometheus" __directory "$storage_path" --owner prometheus --parents
-require="__user/prometheus" __directory "$CONF_DIR"     --owner prometheus --parents
+require="__package_apt/prometheus" __directory "$storage_path" --owner prometheus --parents
 
-__daemontools_service prometheus --run "setuidgid prometheus $GOBIN/prometheus $REAL_FLAGS"
+##### CONFIGURE #############################################################
 
-require="$require __directory/$storage_path __user/prometheus" \
+FLAGS="--storage.tsdb.path $storage_path --storage.tsdb.retention $(($retention_days*24))h"
+
+# TODO it would be neat to restart prometheus on change -- __key_value really should have an --onchange parameter
+require="$require __package_apt/prometheus" \
+__key_value prometheus_args --file /etc/default/prometheus --key "ARGS" --value "\"$FLAGS\"" --delimiter "="
+
+require="$require __directory/$storage_path __package_apt/prometheus" \
 __config_file $CONF \
 	--source $config \
 	--group prometheus --mode 640 \
-	--onchange "$GOBIN/promtool check-config $CONF && svc -h /service/prometheus"
+	--onchange "promtool check config $CONF && service prometheus reload"
 
 for file in $rule_files; do
 	dest=$CONF_DIR/$(basename $file)
-	require="$require __directory/$CONF_DIR __user/prometheus" \
+	require="$require __package_apt/prometheus" \
 	__config_file "$dest" \
 		--source "$file" \
 		--owner prometheus \
-		--onchange "$GOBIN/promtool check-rules '$dest' && svc -h /service/prometheus"
+		--onchange "promtool check rules '$dest' && service prometheus reload"
 done
 

cdist/conf/type/__prometheus_server/parameter/boolean

@@ -0,0 +1 @@
+install-from-backports

cdist/conf/type/__prometheus_server/parameter/required

@@ -1,3 +1 @@
-alertmanager-url
 config
-listen-address