Introduction to MicroProfile Metrics (2018-05-26)

1. Introduction to
MicroProfile Metrics
HASUNUMA Kenji
GlassFish Users Group Japan
k.hasunuma@coppermine.jp
Twitter: @khasunuma
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2. 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
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3. MicroProfie Metrics
• Included MicroProfile 1.2 or later
• Built on JAX-RS and CDI
• Expose system and user metrics
• Using generic text format
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4. Key features
• REST endpoint
• Registry -- i.e. Scope
Base, Vendor and Application
• Format
• Prometheus text format: text/plain
• JSON format: application/json
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5. REST endpoint
• /metrics by default
e.g. http://localhost:8080/metrics
• With Registry (see later)
• /metrics/base
• /metrics/vendor
• /metrics/application
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6. Registry
Store of metrics values:
• Base -- JVM metrics, Required
• Typically obtained from MBean
• Vendor -- Vendor specific metrics
• Application -- User metrics
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7. 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
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8. Format (JSON)
{
"base": {
"cpu.systemLoadAverage": -1,
"thread.count": 90,
"classloader.currentLoadedClass.count": 11150,
"classloader.totalLoadedClass.count": 11193,
},
"vendor": {"system.cpu.load": 0.1491192437579042}
}
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9. Simple Metrics
Counter
Gauge
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10. Complex Metrics
Meter Histogram Timer
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11. 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
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12. To denote metrics
@Inject
@Metric
Counter counter;
Same as ...
- Meter
- Histogram
- Timer
@Gauge
int gauge() {
...
return value;
}
and more ...
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13. To update metrics
• Counter#inc() or Counter#dec()
• Meter#mark()
• Histogram#update()
• Timer#time() & Timer.Context#close()
• Call annotated method:
@Counted, @Metered, @Timed
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14. 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";
}
}
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15. 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}}
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16. 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
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