Treat log's key-values as attributes in log bridge

Cargo.toml

@@ -45,7 +45,7 @@ futures-util = { version = "0.3", default-features = false }
 hyper = { version = "0.14", default-features = false }
 http = { version = "0.2", default-features = false }
 isahc = { version = "1.4", default-features = false }
-log = "0.4"
+log = "0.4.21"
 once_cell = "1.13"
 ordered-float = "4.0"
 pin-project-lite = "0.2"

opentelemetry-appender-log/Cargo.toml

@@ -12,12 +12,16 @@ edition = "2021"
 
 [dependencies]
 opentelemetry = { version = "0.22", path = "../opentelemetry", features = ["logs"]}
-log = { workspace = true, features = ["kv_unstable", "std"]}
+log = { workspace = true, features = ["kv", "std"]}
+serde = { workspace = true, optional = true, features = ["std"] }
 
 [features]
 logs_level_enabled = ["opentelemetry/logs_level_enabled"]
+with_serde = ["log/kv_serde", "serde"]
 default = ["logs_level_enabled"]
 
 [dev-dependencies]
 opentelemetry_sdk = { path = "../opentelemetry-sdk", features = [ "testing", "logs_level_enabled" ] }
+log = { workspace = true, features = ["kv_serde"] }
 tokio = { workspace = true }
+serde = { workspace = true, features = ["std", "derive"] }

opentelemetry-appender-log/examples/logs-basic-in-memory.rs

@@ -25,7 +25,10 @@ async fn main() {
     log::set_max_level(Level::Info.to_level_filter());
 
     // Emit logs using macros from the log crate.
-    error!("hello from {}. My price is {}", "apple", 2.99);
+    let user = "apple";
+    let price = 2.99;
+
+    error!(user, price; "hello from {user}. My price is {price}");
     warn!("warn!");
     info!("test log!");