Introduction to MicroProfile Metrics HASUNUMA Kenji GlassFish Users Group Japan k.hasunuma@coppermine.jp Twitter: @khasunuma #jjug_ccc #ccc_i1

Why not JMX? • JXM/RMI is not easy to deal with • Integration with non-Java is too hard • Microservices may include 
 Java and non-Java environments -> REST based Metrics API #jjug_ccc #ccc_i1 @khasunuma

MicroProfie Metrics • Included MicroProfile 1.2 or later • Built on JAX-RS and CDI • Expose system and user metrics • Using generic text format #jjug_ccc #ccc_i1 @khasunuma

Key features • REST endpoint • Registry -- i.e. Scope
 Base, Vendor and Application • Format • Prometheus text format: text/plain • JSON format: application/json #jjug_ccc #ccc_i1 @khasunuma

REST endpoint • /metrics by default
 e.g. http://localhost:8080/metrics • With Registry (see later) • /metrics/base • /metrics/vendor • /metrics/application #jjug_ccc #ccc_i1 @khasunuma

Registry Store of metrics values: • Base -- JVM metrics, Required • Typically obtained from MBean • Vendor -- Vendor specific metrics • Application -- User metrics #jjug_ccc #ccc_i1 @khasunuma

Format (Prometheus) # TYPE base:cpu_system_load_average gauge # HELP base:cpu_system_load_average Displays... base:cpu_system_load_average -1.0 # TYPE base:thread_count counter # HELP base:thread_count Displays... base:thread_count 90 # TYPE base:classloader_current_loaded_class_count counter # HELP base:classloader_current_loaded_class_count Displays... base:classloader_current_loaded_class_count 11150 # TYPE base:classloader_total_loaded_class_count counter # HELP base:classloader_total_loaded_class_count Displays... base:classloader_total_loaded_class_count 11193 # TYPE vendor:system_cpu_load gauge # HELP vendor:system_cpu_load Display... vendor:system_cpu_load 0.1491192437579042 #jjug_ccc #ccc_i1 @khasunuma

Format (JSON) { "base": { "cpu.systemLoadAverage": -1, "thread.count": 90, "classloader.currentLoadedClass.count": 11150, "classloader.totalLoadedClass.count": 11193, }, "vendor": {"system.cpu.load": 0.1491192437579042} } #jjug_ccc #ccc_i1 @khasunuma

Simple Metrics Counter Gauge #jjug_ccc #ccc_i1 @khasunuma

Complex Metrics Meter Histogram Timer #jjug_ccc #ccc_i1 @khasunuma

How to expose metrics 1. Denote metric(s) as field, method, constructor, parameter or class • The way depends on metric types 2. Fire an event to update metric(s) 3. Show metrics using REST endpoint #jjug_ccc #ccc_i1 @khasunuma

To denote metrics @Inject @Metric Counter counter; Same as ... - Meter - Histogram - Timer @Gauge int gauge() { ... return value; } and more ... #jjug_ccc #ccc_i1 @khasunuma

To update metrics • Counter#inc() or Counter#dec() • Meter#mark() • Histogram#update() • Timer#time() & Timer.Context#close() • Call annotated method:
 @Counted, @Metered, @Timed #jjug_ccc #ccc_i1 @khasunuma

Example: Counter @Path("ping") @ApplicationScoped public class PingResource { // Expose metrics as counter // Metrics is exposed as entity name with package // (Metric name can be customized) @Inject @Metric private Counter counter; // Increment the counter each method call @GET public String ping() { counter.inc(); return "pong"; } } #jjug_ccc #ccc_i1 @khasunuma

Example: Counter $ curl http://localhost:8080/app/rest/ping pong $ curl -H "Accept: application/json" http://localhost:8080/ metrics {"vendor":{"system.cpu.load":0.06088091680189212}, "base":{"classloader.totalLoadedClass.count": 15949,"cpu.systemLoadAverage":-1.0,"thread.count": 158,"classloader.currentLoadedClass.count": 15944,"jvm.uptime":80989,"memory.committedNonHeap": 127795200,"gc.PS MarkSweep.count":4,"memory.committedHeap": 415760384,"thread.max.count":160,"gc.PS Scavenge.count": 21,"cpu.availableProcessors":4,"thread.daemon.count": 144,"classloader.totalUnloadedClass.count": 5,"memory.usedNonHeap":113395160,"memory.maxHeap": 477626368,"memory.usedHeap":77223776,"gc.PS MarkSweep.time": 1394,"memory.maxNonHeap":-1,"gc.PS Scavenge.time":325} "application":{"com.example.app.PingResource.counter":1}} #jjug_ccc #ccc_i1 @khasunuma

What's Metrics? • New feature of MicroProfile 1.2+ • API for expose metrics value • Using REST for polyglot environment • Built on JAX-RS and CDI • Simple, flexible and generic #jjug_ccc #ccc_i1 @khasunuma