Chef report handler for Consul

consul_handler.rb

## chef report handler for Consul
## depends on a chef-client check being registered with the agent
## • pings TTL-style check with ok/warning status on chef run pass/fail
## • stores run report and node attributes in chef/reports/<datacenter>/<consul_node_name>

require "chef/handler"
require "rest_client"

class ConsulHandler < Chef::Handler
    attr_reader :config
    attr_reader :base_url
    
    def initialize(config = {})
        @config = config
        
        @config[:check_id]   ||= "chef-client"
        @config[:agent_port] ||= 8500
        
        ## run_status is not set, yet, so node property will be nil.  defer
        ## setting @config[:report_key_path] until it's needed.
        
        @base_url = "http://localhost:#{config[:agent_port]}/v1"
    end
    
    def report
        if node[:consul][:node_name].nil? or node[:consul][:node_name].empty? then
            Chef::Log.error("empty Consul node name")
        else
            submit_health_check()
            update_report()
        end
    end
    
    private

    def submit_health_check
        ## status is pass, warn, fail
        ## "fail" causes services on this host to be unreachable via Consul
        ## An immediate "fail" feels too strict, but never failing as long as
        ## chef continues to run (and fail) feels too loose.  May need to keep
        ## track of how many chef failures there are and fail after > 1 (?)
        status = run_status.success? ? "pass" : "warn"
        
        params = {}
        
        if run_status.success? then
            params[:note] = "chef run completed successfully in #{run_status.elapsed_time} seconds"
        else
            params[:note] = "chef run failed: #{run_status.formatted_exception}"
        end
        
        Chef::Log.info("submitting Consul health check with status #{status}")
        
        begin
            RestClient.get(
                "#{base_url}/agent/check/#{status}/#{config[:check_id]}",
                :params => params
            )
        rescue RestClient::Exception, Errno::ECONNREFUSED => e
            Chef::Log.error("Could not submit health check to Consul: #{e.message}")
        end
    end
    
    def update_report
        @config[:report_key_path] ||= "chef/reports/#{node[:consul][:datacenter]}"
        full_key_path = "#{config[:report_key_path]}/#{node[:consul][:node_name]}"

        ## *all* recipes! Chef -- at least this version -- doesn't consider foo
        ## and foo::default equivalent, so they would appear twice.
        recipes = node.run_state[:seen_recipes].map{ |k, v| k.include?("::") ? k : k + "::default" }.uniq
        
        report_data = {
            :node_name    => node.name,
            :fqdn         => node["fqdn"],
            :environment  => node.chef_environment,
            :run_list     => node.run_list,
            :roles        => node["roles"],
            :recipes      => recipes,
            :attrs        => {
                :normal    => node.normal_attrs,
                :default   => node.default_attrs,
                :override  => node.override_attrs,
                :automatic => node.automatic_attrs,
            },
            :end_time     => run_status.end_time.utc.iso8601,
            :elapsed_time => run_status.elapsed_time,
        }
        
        Chef::Log.info("updating Consul report at #{full_key_path}")
        
        begin
            RestClient.put(
                "#{base_url}/kv/#{full_key_path}",
                Chef::JSONCompat.to_json(report_data)
            )
        rescue RestClient::Exception, Errno::ECONNREFUSED => e
            Chef::Log.error("Could not submit report data to Consul: #{e.message}")
        end
    end
end