Allow precreation of AttributeSets for metrics (open-telemetry#1421)

Author: KallDrexx

metrics_cached_attrs.rs

@@ -0,0 +1,53 @@
+use lazy_static::lazy_static;
+use opentelemetry::AttributeSet;
+use opentelemetry::{
+    metrics::{Counter, MeterProvider as _},
+    KeyValue,
+};
+use opentelemetry_sdk::metrics::{ManualReader, SdkMeterProvider};
+use rand::{rngs::SmallRng, Rng, SeedableRng};
+use std::borrow::Cow;
+
+mod throughput;
+
+lazy_static! {
+    static ref PROVIDER: SdkMeterProvider = SdkMeterProvider::builder()
+        .with_reader(ManualReader::builder().build())
+        .build();
+    static ref ATTRIBUTE_VALUES: [&'static str; 10] = [
+        "value1", "value2", "value3", "value4", "value5", "value6", "value7", "value8", "value9",
+        "value10"
+    ];
+    static ref COUNTER: Counter<u64> = PROVIDER
+        .meter(<&str as Into<Cow<'static, str>>>::into("test"))
+        .u64_counter("hello")
+        .init();
+    static ref ATTRIBUTE_SETS: Vec<AttributeSet> = {
+        let mut vec = Vec::new();
+        for i0 in 0..ATTRIBUTE_VALUES.len() {
+            for i1 in 0..ATTRIBUTE_VALUES.len() {
+                for i2 in 0..ATTRIBUTE_VALUES.len() {
+                    vec.push(AttributeSet::from(&[
+                        KeyValue::new("attribute1", ATTRIBUTE_VALUES[i0]),
+                        KeyValue::new("attribute2", ATTRIBUTE_VALUES[i1]),
+                        KeyValue::new("attribute3", ATTRIBUTE_VALUES[i2]),
+                    ]))
+                }
+            }
+        }
+
+        vec
+    };
+}
+
+fn main() {
+    throughput::test_throughput(test_counter);
+}
+
+fn test_counter() {
+    let mut rng = SmallRng::from_entropy();
+    let len = ATTRIBUTE_SETS.len();
+    let index = rng.gen_range(0..len);
+
+    COUNTER.add(1, ATTRIBUTE_SETS[index].clone());
+}