From f47c83b63672547aba5ede8db5982a1763e80299 Mon Sep 17 00:00:00 2001
From: Jonatan Ivanov <jonatan.ivanov@gmail.com>
Date: Mon, 27 Mar 2023 16:46:19 -0700
Subject: [PATCH] Hack Timer UX

---
 .../core/instrument/AbstractTimerBuilder.java |  8 +++++
 .../io/micrometer/core/instrument/Timer.java  | 14 +++++---
 .../DistributionStatisticConfig.java          | 14 ++++++++
 .../java/io/micrometer/core/samples/Demo.java | 33 +++++++++++++++++++
 4 files changed, 64 insertions(+), 5 deletions(-)
 create mode 100644 samples/micrometer-samples-core/src/main/java/io/micrometer/core/samples/Demo.java

diff --git a/micrometer-core/src/main/java/io/micrometer/core/instrument/AbstractTimerBuilder.java b/micrometer-core/src/main/java/io/micrometer/core/instrument/AbstractTimerBuilder.java
index 84c57e3227..09c03ab9b2 100644
--- a/micrometer-core/src/main/java/io/micrometer/core/instrument/AbstractTimerBuilder.java
+++ b/micrometer-core/src/main/java/io/micrometer/core/instrument/AbstractTimerBuilder.java
@@ -51,6 +51,14 @@ protected AbstractTimerBuilder(String name) {
         maximumExpectedValue(Duration.ofSeconds(30));
     }
 
+    protected AbstractTimerBuilder(B builder) {
+        this.name = builder.name;
+        tags(builder.tags);
+        this.distributionConfigBuilder = new DistributionStatisticConfig.Builder(builder.distributionConfigBuilder);
+        description(builder.description);
+        pauseDetector(builder.pauseDetector);
+    }
+
     /**
      * @param tags Must be an even number of arguments representing key/value pairs of
      * tags.
diff --git a/micrometer-core/src/main/java/io/micrometer/core/instrument/Timer.java b/micrometer-core/src/main/java/io/micrometer/core/instrument/Timer.java
index 8e6c90caa7..b5f45f85c0 100644
--- a/micrometer-core/src/main/java/io/micrometer/core/instrument/Timer.java
+++ b/micrometer-core/src/main/java/io/micrometer/core/instrument/Timer.java
@@ -27,11 +27,7 @@
 import java.util.Arrays;
 import java.util.concurrent.Callable;
 import java.util.concurrent.TimeUnit;
-import java.util.function.BooleanSupplier;
-import java.util.function.DoubleSupplier;
-import java.util.function.IntSupplier;
-import java.util.function.LongSupplier;
-import java.util.function.Supplier;
+import java.util.function.*;
 
 /**
  * Timer intended to track of a large number of short running events. Example would be
@@ -354,6 +350,14 @@ class Builder extends AbstractTimerBuilder<Builder> {
             super(name);
         }
 
+        Builder(Builder builder) {
+            super(builder);
+        }
+
+        public Function<Tags, Timer> with(MeterRegistry registry) {
+            return tags -> new Builder(this).tags(tags).register(registry);
+        }
+
         @Override
         public Builder tags(String... tags) {
             return super.tags(tags);
diff --git a/micrometer-core/src/main/java/io/micrometer/core/instrument/distribution/DistributionStatisticConfig.java b/micrometer-core/src/main/java/io/micrometer/core/instrument/distribution/DistributionStatisticConfig.java
index c21ebf2832..cbe31c713a 100644
--- a/micrometer-core/src/main/java/io/micrometer/core/instrument/distribution/DistributionStatisticConfig.java
+++ b/micrometer-core/src/main/java/io/micrometer/core/instrument/distribution/DistributionStatisticConfig.java
@@ -272,6 +272,20 @@ public static class Builder {
 
         private final DistributionStatisticConfig config = new DistributionStatisticConfig();
 
+        public Builder() {
+        }
+
+        public Builder(Builder builder) {
+            percentilesHistogram(builder.config.isPublishingHistogram());
+            percentiles(builder.config.getPercentiles());
+            percentilePrecision(builder.config.getPercentilePrecision());
+            serviceLevelObjectives(builder.config.getServiceLevelObjectiveBoundaries());
+            expiry(builder.config.getExpiry());
+            bufferLength(builder.config.getBufferLength());
+            minimumExpectedValue(builder.config.getMinimumExpectedValueAsDouble());
+            maximumExpectedValue(builder.config.getMaximumExpectedValueAsDouble());
+        }
+
         public Builder percentilesHistogram(@Nullable Boolean enabled) {
             config.percentileHistogram = enabled;
             return this;
diff --git a/samples/micrometer-samples-core/src/main/java/io/micrometer/core/samples/Demo.java b/samples/micrometer-samples-core/src/main/java/io/micrometer/core/samples/Demo.java
new file mode 100644
index 0000000000..5e7f141b8e
--- /dev/null
+++ b/samples/micrometer-samples-core/src/main/java/io/micrometer/core/samples/Demo.java
@@ -0,0 +1,33 @@
+package io.micrometer.core.samples;
+
+import io.micrometer.core.instrument.Tags;
+import io.micrometer.core.instrument.Timer;
+import io.micrometer.prometheus.PrometheusConfig;
+import io.micrometer.prometheus.PrometheusMeterRegistry;
+
+import java.time.Duration;
+import java.util.function.Function;
+
+public class Demo {
+
+    private static final PrometheusMeterRegistry registry = new PrometheusMeterRegistry(PrometheusConfig.DEFAULT);
+
+    private static final Function<Tags, Timer> timerFactory = Timer.builder("cache.initialization.latency")
+        .description("Time initialize cache from database")
+        .tag("static", "abc")
+        .publishPercentiles(0.99, 0.999)
+        .publishPercentileHistogram()
+        .minimumExpectedValue(Duration.ofSeconds(10))
+        .maximumExpectedValue(Duration.ofSeconds(600))
+        .with(registry);
+
+    public static void main(String[] args) {
+        doSomething("test");
+    }
+
+    private static void doSomething(String cacheName) {
+        timerFactory.apply(Tags.of("cacheName", cacheName)).record(Duration.ofMillis(100));
+        System.out.println(registry.scrape());
+    }
+
+}