Update keyword "data" -> "buffer", upgrade eventheader version to latest for user-event metrics exporter

opentelemetry-user-events-metrics/Cargo.toml

@@ -13,7 +13,7 @@ rust-version = "1.60"
 [dependencies]
 opentelemetry_api = { version = "0.19", path = "../opentelemetry-api", features = ["metrics"] }
 opentelemetry_sdk = { version = "0.19", path = "../opentelemetry-sdk", features = ["metrics", "rt-tokio"] }
-eventheader = { version = "= 0.2.0" }
+eventheader = { version = "= 0.3.1" }
 opentelemetry-proto = { version = "0.2", path = "../opentelemetry-proto", features = ["gen-tonic", "metrics"] }
 async-trait = "0.1"
 prost = "0.11"

opentelemetry-user-events-metrics/src/tracepoint/mod.rs

@@ -12,39 +12,39 @@ use std::pin::Pin;
 /// For this event:
 ///
 /// - Event is named "otlp_metrics".
-/// - Field 1 is named "data" and has type "variable-length array of u8".
+/// - Field 1 is named "buffer" and has type "variable-length array of u8".
 ///
 /// "__rel_loc" is a special type for variable-length fields. It requires
 /// special handling in the write() method.
-const METRICS_EVENT_DEF: &[u8] = b"otlp_metrics __rel_loc u8[] data\0";
+const METRICS_EVENT_DEF: &[u8] = b"otlp_metrics __rel_loc u8[] buffer\0";
 
 /// If the tracepoint is registered and enabled, writes an event. If the tracepoint
 /// is unregistered or disabled, this does nothing and returns 0. You should usually
-/// check [`enabled()`] and only build the data and call `write()` if `enabled()`
+/// check [`enabled()`] and only build the buffer and call `write()` if `enabled()`
 /// returns true.
 ///
-/// Requires: data.len() < 65536.
+/// Requires: buffer.len() < 65536.
 ///
 /// Return value is 0 for success or an errno code for error. The return value is
 /// provided to help with debugging and should usually be ignored in release builds.
-pub fn write(trace_point: &ehi::TracepointState, data: &[u8]) -> i32 {
+pub fn write(trace_point: &ehi::TracepointState, buffer: &[u8]) -> i32 {
     // This must stay in sync with the METRICS_EVENT_DEF string.
-    // Return error -1 if data exceeds max size
-    if data.len() > u16::MAX as usize {
-        eprintln!("Data exceeds max length.");
+    // Return error -1 if buffer exceeds max size
+    if buffer.len() > u16::MAX as usize {
+        eprintln!("Buffer exceeds max length.");
         return -1;
     }
 
-    // The rel_loc for the data field stores the size and offset of the data.
-    // - High 16 bits store the size = data.len()
-    // - Low 16 bits store the offset of the data from the end of the rel_loc field = 0.
-    let data_rel_loc: u32 = (data.len() as u32) << 16;
+    // The rel_loc for the buffer field stores the size and offset of the buffer.
+    // - High 16 bits store the size = buffer.len()
+    // - Low 16 bits store the offset of the buffer from the end of the rel_loc field = 0.
+    let buffer_rel_loc: u32 = (buffer.len() as u32) << 16;
 
     trace_point.write(&mut [
         // mut because the write method does some fix-ups.
         ehi::EventDataDescriptor::zero(), // First item in array MUST be zero().
-        ehi::EventDataDescriptor::from_value(&data_rel_loc), // rel_loc for the data field.
-        ehi::EventDataDescriptor::from_slice(data), // data field.
+        ehi::EventDataDescriptor::from_value(&buffer_rel_loc), // rel_loc for the buffer field.
+        ehi::EventDataDescriptor::from_slice(buffer), // buffer field.
     ])
 }