# 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 to exclude (example: consul-agent-http,mesos-slave,mesos-agent-watcher)
<%

  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 = (ENV['EXCLUDE_SERVICES'] || '').split(',')
  # Compute the health of a Service
  def compute_state(snode)
    states = ['passing', []]
    snode['Checks'].each do |chk|
      st = chk['Status']
      states[1] << st
      if st == 'critical'
        states[0] = st
      elsif st == 'warning' && states[0] == 'passing'
        states[0] = st
      end
    end
    states
  end
  backends = {}
  service_count = 0
  services(tag: service_tag_filter).each do |service_name, tags|
    if !services_blacklist.include?(service_name) && (instance_must_tag.nil? || tags.include?(instance_must_tag))
      service_count += 1
      res = {
        'passing'  => 0,
        'warning'  => 0,
        'critical' => 0,
      }
      service(service_name).each do |snode|
        state = compute_state(snode)[0]
        res[state] += 1
      end
      backends[service_name] = {
        state: res,
        stats: service(service_name).endpoint.stats,
      }
    end
  end
%>
# HELP consul_datacenters_count A gauge of number of datacenters available
# TYPE consul_nodes_count gauge
consul_datacenters_count <%= datacenters().count %> <%= datacenters().endpoint.stats.last_success_or_error.to_i * 1000 %>

# HELP consul_nodes_count A gauge of number of nodes in the cluster
# TYPE consul_nodes_count gauge
consul_nodes_count <%= nodes().count %> <%= nodes().endpoint.stats.last_success_or_error.to_i * 1000 %>

# HELP consul_services_count A gauge of the number of services
# TYPE consul_services_count gauge
consul_services_count <%= service_count %> <%= services(tag: service_tag_filter).endpoint.stats.last_success_or_error.to_i * 1000 %>

# 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

<%
  json_backends = {}
  now = Time.now.utc
  backends.each_pair do |service_name, service_info|
    service_info[:state].each_pair do |state_name, state_count|
%>consul_service_count{service="<%= service_name %>",state="<%= state_name %>"} <%= state_count %>
<%
    end
    current_stats = service_info[:stats]
%>consul_service_stats_requests_total{service="<%= service_name %>",type="success"} <%= current_stats.successes %>
<%
    if current_stats.errors > 0
%>consul_service_stats_requests_total{service="<%= service_name %>",type="errors"} <%= current_stats.errors %>
<%
    end
%>consul_service_stats_requests_bytes{service="<%= service_name %>"} <%= service_info[:stats].body_bytes %>
consul_service_stats_requests_bytes_per_sec{service="<%= service_name %>"} <%= service_info[:stats].bytes_per_sec(now) %>
consul_service_changes_total{service="<%= service_name %>"} <%= service_info[:stats].changes %>

<%
  end
%>