# A template for exporting metrics for prometheus using consul-templaterb
# This template can be configure the following way with environment variables
# Environment variables to filter services/instances
#   SERVICES_TAG_FILTER: basic tag filter for service (default HTTP)
#   INSTANCE_MUST_TAG: Second level of filtering (optional, default to SERVICES_TAG_FILTER)
#   INSTANCE_EXCLUDE_TAG: Exclude instances having the given tag
#   EXCLUDE_SERVICES: comma-separated services regexps to exclude (example: lbl7.*,netsvc-probe.*,consul-probed.*)
#   PROMETHEUS_EXPORTED_SERVICE_META: comma-separated list of meta to export into metrics of service
<%
  service_metas_to_export = (ENV['PROMETHEUS_EXPORTED_SERVICE_META'] || 'OWNERS,version,os,criteo_flavor,node_group').split(',')

  service_tag_filter = ENV['SERVICES_TAG_FILTER'] || nil
  instance_must_tag = ENV['INSTANCE_MUST_TAG'] || service_tag_filter
  instance_exclude_tag = ENV['INSTANCE_EXCLUDE_TAG']

  # Services to hide
  services_blacklist_raw = (ENV['EXCLUDE_SERVICES'] || 'lbl7.*,netsvc-probe.*,consul-probed.*').split(',')
  services_blacklist = services_blacklist_raw.map { |v| Regexp.new(v) }

  backends = {}
  all_stats = {}
  service_count = 0

  statuses = agent_members().map {|m| m.status}.reduce({}) do |sum, s|
    v = sum[s] || 0
    sum[s] = v + 1
    sum
  end
%>
# HELP consul_members_count A gauge of number of serf members with their count and their status('alive', 'leaving', 'left', 'failed')
# TYPE consul_members_count gauge
<%
  statuses.each do |k, v|
%>
consul_members_count{serf="lan",status="<%= k %>"} <%= v %><%
  end

  services(tag: service_tag_filter).each do |service_name, tags|
    if !services_blacklist.any? {|r| r.match(service_name)} && (instance_must_tag.nil? || tags.include?(instance_must_tag))
      service_count += 1
      srv = service(service_name)
      all_stats[service_name] = srv.endpoint.stats
      srv.each do |snode|
        key = "#{snode['Service']['Service']}"
        metas = {}
        service_kind = snode['Service']['Kind']
        metas['__service_kind'] = service_kind if service_kind
        service_metas_to_export.each do |k|
          meta = snode.service_or_node_meta_value(k)
          if meta
            key += "::#{k}=#{meta}"
            metas[k] = meta
          end
        end
        back = backends[key]
        if back.nil?
          back = {
            metas: metas,
            service_name: service_name,
            state: {
              'passing' =>  {
                instances: 0,
                weight: 0
              },
              'warning' =>  {
                instances: 0,
                weight: 0
              },
              'critical' =>  {
                instances: 0,
                weight: 0
              }
            }
          }
          backends[key] = back
        end
        state = snode.status
        # Increment instance number.
        back[:state][state][:instances] += 1
        # Increment total weight regarding current node's state.
        if state == 'passing'
          back[:state][state][:weight] += snode['Service']['Weights']['Passing']
        elsif state == 'warning'
          back[:state][state][:weight] += snode['Service']['Weights']['Warning']
        end
      end
    end
  end
%>
# HELP consul_datacenters_count A gauge of number of datacenters available
# TYPE consul_nodes_count gauge
consul_datacenters_count <%= datacenters().count %>

# HELP consul_nodes_count A gauge of number of nodes in the cluster
# TYPE consul_nodes_count gauge
consul_nodes_count <%= nodes().count %>

# HELP consul_services_count A gauge of the number of services
# TYPE consul_services_count gauge
consul_services_count <%= service_count %>

<%
%i[success errors bytes_read changes network_bytes].each do |sym|
%>
# HELP consul_net_info_<%= sym.to_s %> consul-templaterb global stats for <%= sym.to_s %>
# TYPE consul_net_info_<%= sym.to_s %> counter
consul_net_info_<%= sym.to_s %> <%= @net_info[sym] %>
<%
end
%>

# HELP consul_service_count A gauge of number instances of service with their current state
# TYPE consul_service_count gauge
# HELP consul_service_stats_requests_total A counter of requests performed by consul-templaterb, shows activity on a service
# TYPE consul_service_stats_requests_total counter
# HELP consul_service_stats_requests_bytes A counter of bytes transfered from Consul Agent to consul-templaterb
# TYPE consul_service_stats_requests_bytes counter
# HELP consul_service_stats_requests_bytes_per_sec A counter of bytes transfered from Consul Agent to consul-templaterb
# TYPE consul_service_stats_requests_bytes_per_sec gauge
# HELP consul_service_changes_total A counter of changes that occured on a service
# TYPE consul_service_changes_total counter

<%
  def escape_meta(val)
    val.gsub('"', '\"')
  end

  json_backends = {}
  now = Time.now.utc
  backends.each_pair do |k, service_info|
    service_name = service_info[:service_name]
    meta_string = ""
    service_info[:metas].each_pair do |k,v|
      meta_string+=",#{k}=\"#{escape_meta(v)}\""
    end
    service_info[:state].each_pair do |state_name, state_count|
%>consul_service_count{service="<%= service_name %>",state="<%= state_name %>"<%= meta_string %>} <%= state_count[:instances] %>
consul_service_weight{service="<%= service_name %>",state="<%= state_name %>"<%= meta_string %>} <%= state_count[:weight] %>
<%
    end
  end

  # Global statistics
  all_stats.each_pair do |service_name, current_stats|
%>consul_service_stats_requests_total{service="<%= escape_meta(service_name) %>",type="success"} <%= current_stats.successes %>
<%
    if current_stats.errors > 0
%>consul_service_stats_requests_total{service="<%= escape_meta(service_name) %>",type="errors"} <%= current_stats.errors %>
<%
    end
%>consul_service_stats_requests_bytes{service="<%= escape_meta(service_name) %>"} <%= current_stats.body_bytes %>
consul_service_stats_requests_bytes_per_sec{service="<%= escape_meta(service_name) %>"} <%= current_stats.bytes_per_sec(now) %>
consul_service_changes_total{service="<%= escape_meta(service_name) %>"} <%= current_stats.changes %>

<%
  end
%>