Convert Value::String type to Cow<'static, str> (see #317)

examples/actix-http/src/main.rs

@@ -38,7 +38,8 @@ async fn main() -> std::io::Result<()> {
             .wrap(Logger::default())
             .wrap_fn(move |req, srv| {
                 tracer.in_span("middleware", move |cx| {
-                    cx.span().set_attribute(Key::new("path").string(req.path()));
+                    cx.span()
+                        .set_attribute(Key::new("path").string(req.path().to_string()));
                     srv.call(req).with_context(cx)
                 })
             })

examples/actix-udp/src/main.rs

@@ -38,7 +38,8 @@ async fn main() -> std::io::Result<()> {
             .wrap_fn(|req, srv| {
                 let tracer = global::tracer("request");
                 tracer.in_span("middleware", move |cx| {
-                    cx.span().set_attribute(Key::new("path").string(req.path()));
+                    cx.span()
+                        .set_attribute(Key::new("path").string(req.path().to_string()));
                     srv.call(req).with_context(cx)
                 })
             })

opentelemetry-contrib/src/datadog/model/v03.rs

@@ -27,7 +27,7 @@ pub(crate) fn encode(service_name: &str, spans: Vec<trace::SpanData>) -> Result<
         if let Some(Value::String(s)) = span.attributes.get(&Key::new("span.type")) {
             rmp::encode::write_map_len(&mut encoded, 11)?;
             rmp::encode::write_str(&mut encoded, "type")?;
-            rmp::encode::write_str(&mut encoded, s.as_str())?;
+            rmp::encode::write_str(&mut encoded, s.as_ref())?;
         } else {
             rmp::encode::write_map_len(&mut encoded, 10)?;
         }

opentelemetry-contrib/src/datadog/model/v05.rs

@@ -94,7 +94,7 @@ fn encode_spans(
             .unwrap_or(0);
 
         let span_type = match span.attributes.get(&Key::new("span.type")) {
-            Some(Value::String(s)) => interner.intern(s.as_str()),
+            Some(Value::String(s)) => interner.intern(s.as_ref()),
             _ => interner.intern(""),
         };
 

opentelemetry-jaeger/src/lib.rs

@@ -474,7 +474,7 @@ impl Into<jaeger::Tag> for KeyValue {
     fn into(self) -> jaeger::Tag {
         let KeyValue { key, value } = self;
         match value {
-            Value::String(s) => jaeger::Tag::new(key.into(), jaeger::TagType::String, Some(s), None, None, None, None),
+            Value::String(s) => jaeger::Tag::new(key.into(), jaeger::TagType::String, Some(s.into()), None, None, None, None),
             Value::F64(f) => jaeger::Tag::new(key.into(), jaeger::TagType::Double, None, Some(f.into()), None, None, None),
             Value::Bool(b) => jaeger::Tag::new(key.into(), jaeger::TagType::Bool, None, None, Some(b), None, None),
             Value::I64(i) => jaeger::Tag::new(key.into(), jaeger::TagType::Long, None, None, None, Some(i), None),

opentelemetry-otlp/src/transform/common.rs

@@ -44,7 +44,7 @@ impl From<Value> for AnyValue {
             Value::Bool(val) => any_value.set_bool_value(val),
             Value::I64(val) => any_value.set_int_value(val),
             Value::F64(val) => any_value.set_double_value(val),
-            Value::String(val) => any_value.set_string_value(val),
+            Value::String(val) => any_value.set_string_value(val.into_owned()),
             Value::Array(vals) => any_value.set_array_value({
                 let mut array_value = ArrayValue::new();
                 array_value.set_values(RepeatedField::from_vec(

opentelemetry/src/api/baggage.rs

@@ -39,7 +39,7 @@ impl Baggage {
     /// let mut cc = Baggage::new();
     /// let _ = cc.insert("my-name", "my-value");
     ///
-    /// assert_eq!(cc.get("my-name"), Some(&Value::String("my-value".to_string())))
+    /// assert_eq!(cc.get("my-name"), Some(&Value::from("my-value")))
     /// ```
     pub fn get<T: Into<Key>>(&self, key: T) -> Option<&Value> {
         self.inner.get(&key.into()).map(|(value, _metadata)| value)
@@ -55,7 +55,7 @@ impl Baggage {
     /// let _ = cc.insert("my-name", "my-value");
     ///
     /// // By default, the metadata is empty
-    /// assert_eq!(cc.get_with_metadata("my-name"), Some(&(Value::String("my-value".to_string()), BaggageMetadata::from(""))))
+    /// assert_eq!(cc.get_with_metadata("my-name"), Some(&(Value::from("my-value"), BaggageMetadata::from(""))))
     /// ```
     pub fn get_with_metadata<T: Into<Key>>(&self, key: T) -> Option<&(Value, BaggageMetadata)> {
         self.inner.get(&key.into())
@@ -74,7 +74,7 @@ impl Baggage {
     /// let mut cc = Baggage::new();
     /// let _ = cc.insert("my-name", "my-value");
     ///
-    /// assert_eq!(cc.get("my-name"), Some(&Value::String("my-value".to_string())))
+    /// assert_eq!(cc.get("my-name"), Some(&Value::from("my-value")))
     /// ```
     pub fn insert<K, V>(&mut self, key: K, value: V) -> Option<Value>
     where
@@ -98,7 +98,7 @@ impl Baggage {
     /// let mut cc = Baggage::new();
     /// let _ = cc.insert_with_metadata("my-name", "my-value", "test");
     ///
-    /// assert_eq!(cc.get_with_metadata("my-name"), Some(&(Value::String("my-value".to_string()), BaggageMetadata::from("test"))))
+    /// assert_eq!(cc.get_with_metadata("my-name"), Some(&(Value::from("my-value"), BaggageMetadata::from("test"))))
     /// ```
     pub fn insert_with_metadata<K, V, S>(
         &mut self,
@@ -257,7 +257,7 @@ pub trait BaggageExt {
     ///
     /// assert_eq!(
     ///     cx.baggage().get("my-name"),
-    ///     Some(&Value::String("my-value".to_string())),
+    ///     Some(&Value::from("my-value")),
     /// )
     /// ```
     fn with_baggage<T: IntoIterator<Item = I>, I: Into<KeyValueMetadata>>(
@@ -276,7 +276,7 @@ pub trait BaggageExt {
     ///
     /// assert_eq!(
     ///     cx.baggage().get("my-name"),
-    ///     Some(&Value::String("my-value".to_string())),
+    ///     Some(&Value::from("my-value")),
     /// )
     /// ```
     fn current_with_baggage<T: IntoIterator<Item = I>, I: Into<KeyValueMetadata>>(

opentelemetry/src/api/core.rs

@@ -44,7 +44,7 @@ impl Key {
     }
 
     /// Create a `KeyValue` pair for `String` values.
-    pub fn string<T: Into<String>>(&self, value: T) -> KeyValue {
+    pub fn string<T: Into<Cow<'static, str>>>(&self, value: T) -> KeyValue {
         KeyValue {
             key: self.clone(),
             value: Value::String(value.into()),
@@ -97,7 +97,7 @@ pub enum Value {
     /// f64 values
     F64(f64),
     /// String values
-    String(String),
+    String(Cow<'static, str>),
     /// Array of homogeneous values
     Array(Vec<Value>),
 }
@@ -122,14 +122,20 @@ from_values!(
     (bool, Value::Bool);
     (i64, Value::I64);
     (f64, Value::F64);
-    (String, Value::String);
     (Vec<Value>, Value::Array);
 );
 
-impl From<&str> for Value {
-    /// Convenience method for creating a `Value` from a `&str`.
-    fn from(value_str: &str) -> Self {
-        Value::String(value_str.to_string())
+impl From<&'static str> for Value {
+    /// Convenience method for creating a `Value` from a `&'static str`.
+    fn from(s: &'static str) -> Self {
+        Value::String(s.into())
+    }
+}
+
+impl From<String> for Value {
+    /// Convenience method for creating a `Value` from a `String`.
+    fn from(s: String) -> Self {
+        Value::String(s.into())
     }
 }
 
@@ -141,7 +147,7 @@ impl From<Value> for String {
             Value::Bool(value) => value.to_string(),
             Value::I64(value) => value.to_string(),
             Value::F64(value) => value.to_string(),
-            Value::String(value) => value,
+            Value::String(value) => value.into_owned(),
             Value::Array(value) => format_value_array_as_string(&value),
         }
     }
@@ -155,7 +161,7 @@ impl From<&Value> for String {
             Value::Bool(value) => value.to_string(),
             Value::I64(value) => value.to_string(),
             Value::F64(value) => value.to_string(),
-            Value::String(value) => value.clone(),
+            Value::String(value) => value.to_string(),
             Value::Array(value) => format_value_array_as_string(value),
         }
     }

opentelemetry/src/exporter/metrics/stdout.rs

@@ -135,7 +135,7 @@ where
             let encoded_inst_labels = if !desc.instrumentation_name().is_empty() {
                 let inst_labels = LabelSet::from_labels(iter::once(KeyValue::new(
                     "instrumentation.name",
-                    desc.instrumentation_name(),
+                    desc.instrumentation_name().to_owned(),
                 )));
                 inst_labels.encoded(Some(self.label_encoder.as_ref()))
             } else {

opentelemetry/src/sdk/env.rs

@@ -62,7 +62,7 @@ mod tests {
     use crate::sdk::env::OTEL_RESOURCE_ATTRIBUTES;
     use crate::sdk::resource::{Resource, ResourceDetector};
     use crate::sdk::EnvResourceDetector;
-    use crate::{Key, KeyValue, Value};
+    use crate::{Key, KeyValue};
     use std::{env, time};
 
     #[test]
@@ -75,13 +75,10 @@ mod tests {
         assert_eq!(
             resource,
             Resource::new(vec![
-                KeyValue::new(
-                    Key::new("key".to_string()),
-                    Value::String("value".to_string())
-                ),
-                KeyValue::new(Key::new("k".to_string()), Value::String("v".to_string())),
-                KeyValue::new(Key::new("a".to_string()), Value::String("x".to_string())),
-                KeyValue::new(Key::new("a".to_string()), Value::String("z".to_string()))
+                KeyValue::new(Key::new("key".to_string()), "value"),
+                KeyValue::new(Key::new("k".to_string()), "v"),
+                KeyValue::new(Key::new("a".to_string()), "x"),
+                KeyValue::new(Key::new("a".to_string()), "z"),
             ])
         );
 

opentelemetry/src/sdk/propagation/baggage.rs

@@ -246,7 +246,7 @@ mod tests {
                 vec![
                     KeyValue::new("key1", Value::Array(vec![Value::Bool(true), Value::Bool(false)])),
                     KeyValue::new("key2", Value::Array(vec![Value::I64(123), Value::I64(456)])),
-                    KeyValue::new("key3", Value::Array(vec![Value::String("val1".to_string()), Value::String("val2".to_string())])),
+                    KeyValue::new("key3", Value::Array(vec!["val1".into(), "val2".into()])),
                 ],
                 vec![
                     "key1=[true%2Cfalse]",

opentelemetry/src/sdk/resource.rs

@@ -243,13 +243,10 @@ mod tests {
         assert_eq!(
             resource,
             Resource::new(vec![
-                KeyValue::new(
-                    Key::new("key".to_string()),
-                    Value::String("value".to_string())
-                ),
-                KeyValue::new(Key::new("k".to_string()), Value::String("v".to_string())),
-                KeyValue::new(Key::new("a".to_string()), Value::String("x".to_string())),
-                KeyValue::new(Key::new("a".to_string()), Value::String("z".to_string()))
+                KeyValue::new(Key::new("key".to_string()), "value"),
+                KeyValue::new(Key::new("k".to_string()), "v"),
+                KeyValue::new(Key::new("a".to_string()), "x"),
+                KeyValue::new(Key::new("a".to_string()), "z")
             ])
         )
     }