Class: PrometheusExporter::Server::WebServer
- Inherits:
-
Object
- Object
- PrometheusExporter::Server::WebServer
- Defined in:
- lib/prometheus_exporter/server/web_server.rb
Instance Attribute Summary collapse
-
#collector ⇒ Object
readonly
Returns the value of attribute collector.
Instance Method Summary collapse
- #add_gauge(name, help, value) ⇒ Object
- #get_rss ⇒ Object
- #handle_metrics(req, res) ⇒ Object
-
#initialize(port:, collector: nil) ⇒ WebServer
constructor
A new instance of WebServer.
- #metrics ⇒ Object
- #start ⇒ Object
- #stop ⇒ Object
Constructor Details
#initialize(port:, collector: nil) ⇒ WebServer
Returns a new instance of WebServer.
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# File 'lib/prometheus_exporter/server/web_server.rb', line 12 def initialize(port: , collector: nil) @total_metrics = PrometheusExporter::Metric::Counter.new("total_collector_metrics", "total metrics processed by exporter web") @total_sessions = PrometheusExporter::Metric::Counter.new("total_collector_sessions", "total send_metric sessions processed by exporter web") @total_bad_metrics = PrometheusExporter::Metric::Counter.new("total_collector_bad_metrics", "total mis-handled metrics by collector") @server = WEBrick::HTTPServer.new( Port: port, AccessLog: [], Logger: WEBrick::Log.new("/dev/null") ) @collector = collector || Collector.new @port = port @server.mount_proc '/' do |req, res| res['ContentType'] = 'text/plain; charset=utf-8' if req.path == '/metrics' res.status = 200 if req.header["accept-encoding"].to_s.include?("gzip") sio = StringIO.new collected_metrics = metrics begin writer = Zlib::GzipWriter.new(sio) writer.write(collected_metrics) ensure writer.close end res.body = sio.string res.header["content-encoding"] = "gzip" else res.body = metrics end elsif req.path == '/send-metrics' handle_metrics(req, res) else res.status = 404 res.body = "Not Found! The Prometheus Discourse plugin only listens on /metrics and /send-metrics" end end end |
Instance Attribute Details
#collector ⇒ Object (readonly)
Returns the value of attribute collector.
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# File 'lib/prometheus_exporter/server/web_server.rb', line 10 def collector @collector end |
Instance Method Details
#add_gauge(name, help, value) ⇒ Object
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# File 'lib/prometheus_exporter/server/web_server.rb', line 129 def add_gauge(name, help, value) gauge = PrometheusExporter::Metric::Gauge.new(name, help) gauge.observe(value) gauge end |
#get_rss ⇒ Object
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# File 'lib/prometheus_exporter/server/web_server.rb', line 123 def get_rss @pagesize ||= `getconf PAGESIZE`.to_i rescue 4096 @pid ||= Process.pid File.read("/proc/#{@pid}/statm").split(' ')[1].to_i * @pagesize rescue 0 end |
#handle_metrics(req, res) ⇒ Object
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# File 'lib/prometheus_exporter/server/web_server.rb', line 56 def handle_metrics(req, res) @total_sessions.observe req.body do |block| begin @total_metrics.observe @collector.process(block) rescue => e @total_bad_metrics.observe res.body = "Bad Metrics #{e}" res.status = e.respond_to?(:status_code) ? e.status_code : 500 return end end res.body = "OK" res.status = 200 end |
#metrics ⇒ Object
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# File 'lib/prometheus_exporter/server/web_server.rb', line 88 def metrics metric_text = nil begin Timeout::timeout(2) do metric_text = @collector.prometheus_metrics_text end rescue Timeout::Error # we timed out ... bummer STDERR.puts "Generating Prometheus metrics text timed out" end metrics = [] metrics << add_gauge( "collector_working", "Is the master process collector able to collect metrics", metric_text && metric_text.length > 0 ? 1 : 0 ) metrics << add_gauge( "collector_rss", "total memory used by collector process", get_rss ) metrics << @total_metrics metrics << @total_sessions metrics << @total_bad_metrics <<~TEXT #{metrics.map(&:to_prometheus_text).join("\n\n")} #{metric_text} TEXT end |
#start ⇒ Object
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# File 'lib/prometheus_exporter/server/web_server.rb', line 74 def start @runner ||= Thread.start do begin @server.start rescue => e STDERR.puts "Failed to start prometheus collector web on port #{@port}: #{e}" end end end |
#stop ⇒ Object
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# File 'lib/prometheus_exporter/server/web_server.rb', line 84 def stop @server.shutdown end |