refactor!: make our own key-value type

.github/workflows/ci.yml

@@ -99,7 +99,7 @@ jobs:
           cargo run --features="starter-log" --example single_file
           cargo run --features="starter-log,diagnostic-task-local" --example task_local
           cargo run --features="starter-log,append-async" --example asynchronous
-          cargo run --features="starter-log,diagnostic-fastrace,layout-google-cloud-logging" --example google_cloud_logging
+          cargo run --features="starter-log,bridge-log-serde,diagnostic-fastrace,layout-google-cloud-logging" --example google_cloud_logging
           cargo run --features="starter-log,append-fastrace,diagnostic-fastrace" --example fastrace
 
           cargo test --features="starter-log" --example testing -- --show-output

Cargo.toml

@@ -62,7 +62,7 @@ fasyslog = { version = "1.0.0" }
 insta = { version = "1.43.2" }
 jiff = { version = "0.2" }
 libc = { version = "0.2.162" }
-log = { version = "0.4.27", features = ["kv_std", "kv_sval"] }
+log = { version = "0.4.27", default-features = false }
 oneshot = { version = "0.2.1", default-features = false, features = ["std"] }
 opentelemetry = { version = "0.32.0", default-features = false }
 opentelemetry-otlp = { version = "0.32.0", default-features = false }
@@ -73,7 +73,6 @@ serde = { version = "1.0", features = ["derive"] }
 serde_json = { version = "1.0" }
 tempfile = { version = "3.16" }
 tokio = { version = "1.47.1" }
-value-bag = { version = "1.11.1", features = ["inline-i128", "owned", "sval"] }
 which = { version = "8.0.0" }
 
 [workspace.lints.rust]

appenders/async/src/append.rs

@@ -159,7 +159,7 @@ impl AsyncBuilder {
 struct DiagnosticCollector<'a>(&'a mut Vec<(kv::KeyOwned, kv::ValueOwned)>);
 
 impl<'a> Visitor for DiagnosticCollector<'a> {
-    fn visit(&mut self, key: kv::Key, value: kv::Value) -> Result<(), Error> {
+    fn visit(&mut self, key: kv::KeyView, value: kv::ValueView) -> Result<(), Error> {
         self.0.push((key.to_owned(), value.to_owned()));
         Ok(())
     }

appenders/async/src/worker.rs

@@ -54,7 +54,7 @@ impl Worker {
                     let diags: &[Box<dyn Diagnostic>] = if diags.is_empty() {
                         &[]
                     } else {
-                        &[Box::new(OwnedDiagnostic(diags))]
+                        &[Box::new(AsyncDiagnostic(diags))]
                     };
 
                     record.with(|record| {
@@ -80,12 +80,12 @@ impl Worker {
 }
 
 #[derive(Debug)]
-struct OwnedDiagnostic(Vec<(kv::KeyOwned, kv::ValueOwned)>);
+struct AsyncDiagnostic(Vec<(kv::KeyOwned, kv::ValueOwned)>);
 
-impl Diagnostic for OwnedDiagnostic {
+impl Diagnostic for AsyncDiagnostic {
     fn visit(&self, visitor: &mut dyn Visitor) -> Result<(), Error> {
         for (key, value) in &self.0 {
-            visitor.visit(key.by_ref(), value.by_ref())?;
+            visitor.visit(key.view(), value.view())?;
         }
         Ok(())
     }

appenders/fastrace/src/lib.rs

@@ -23,8 +23,8 @@ use jiff::Zoned;
 use logforth_core::Diagnostic;
 use logforth_core::Error;
 use logforth_core::append::Append;
-use logforth_core::kv::Key;
-use logforth_core::kv::Value;
+use logforth_core::kv::KeyView;
+use logforth_core::kv::ValueView;
 use logforth_core::kv::Visitor;
 use logforth_core::record::Record;
 
@@ -68,12 +68,7 @@ impl Append for FastraceEvent {
                     (Cow::from("timestamp"), Cow::from(Zoned::now().to_string())),
                 ]
                 .into_iter()
-                .chain(
-                    collector
-                        .kv
-                        .into_iter()
-                        .map(|(k, v)| (Cow::from(k), Cow::from(v))),
-                )
+                .chain(collector.kv)
             },
         ));
 
@@ -87,12 +82,18 @@ impl Append for FastraceEvent {
 }
 
 struct KvCollector {
-    kv: Vec<(String, String)>,
+    kv: Vec<(Cow<'static, str>, Cow<'static, str>)>,
 }
 
 impl Visitor for KvCollector {
-    fn visit(&mut self, key: Key, value: Value) -> Result<(), Error> {
-        self.kv.push((key.to_string(), value.to_string()));
+    fn visit(&mut self, key: KeyView, value: ValueView) -> Result<(), Error> {
+        let k = key.to_cow();
+        let v = if let Some(s) = value.to_static_str() {
+            Cow::Borrowed(s)
+        } else {
+            Cow::Owned(value.to_string())
+        };
+        self.kv.push((k, v));
         Ok(())
     }
 }

appenders/journald/src/field.rs

@@ -18,7 +18,7 @@
 
 use std::io::Write;
 
-use logforth_core::kv::Value;
+use logforth_core::kv::ValueView;
 
 pub(super) enum FieldName<'a> {
     WellFormed(&'a str),
@@ -90,7 +90,7 @@ impl PutAsFieldValue for std::fmt::Arguments<'_> {
     }
 }
 
-impl PutAsFieldValue for Value<'_> {
+impl PutAsFieldValue for ValueView<'_> {
     fn put_field_value(self, buffer: &mut Vec<u8>) {
         // SAFETY: no more than an allocate-less version
         //  buffer.extend_from_slice(format!("{}", self))

appenders/journald/src/lib.rs

@@ -24,8 +24,8 @@ use std::os::unix::net::UnixDatagram;
 use logforth_core::Append;
 use logforth_core::Diagnostic;
 use logforth_core::Error;
-use logforth_core::kv::Key;
-use logforth_core::kv::Value;
+use logforth_core::kv::KeyView;
+use logforth_core::kv::ValueView;
 use logforth_core::kv::Visitor;
 use logforth_core::record::Level;
 use logforth_core::record::Record;
@@ -237,7 +237,7 @@ impl Journald {
 struct WriteKeyValues<'a>(&'a mut Vec<u8>);
 
 impl Visitor for WriteKeyValues<'_> {
-    fn visit(&mut self, key: Key, value: Value) -> Result<(), Error> {
+    fn visit(&mut self, key: KeyView, value: ValueView) -> Result<(), Error> {
         let key = key.as_str();
         field::put_field_length_encoded(self.0, field::FieldName::WriteEscaped(key), value);
         Ok(())

appenders/opentelemetry/src/lib.rs

@@ -18,19 +18,21 @@
 #![deny(missing_docs)]
 
 use std::borrow::Cow;
+use std::collections::HashMap;
 use std::fmt;
 use std::time::SystemTime;
 
 use logforth_core::Diagnostic;
 use logforth_core::Error;
 use logforth_core::Layout;
 use logforth_core::append::Append;
-use logforth_core::kv::Key;
-use logforth_core::kv::Value;
+use logforth_core::kv::KeyView;
+use logforth_core::kv::ValueView;
 use logforth_core::kv::Visitor;
 use logforth_core::record::Level;
 use logforth_core::record::Record;
 use opentelemetry::InstrumentationScope;
+use opentelemetry::Key;
 use opentelemetry::logs::AnyValue;
 use opentelemetry::logs::LogRecord;
 use opentelemetry::logs::Logger;
@@ -361,10 +363,67 @@ struct KvExtractor<'a> {
 }
 
 impl Visitor for KvExtractor<'_> {
-    fn visit(&mut self, key: Key, value: Value) -> Result<(), Error> {
-        let key = key.to_cow();
-        let value = value.to_string();
+    fn visit(&mut self, key: KeyView, value: ValueView) -> Result<(), Error> {
+        let key = key_to_key(key);
+        let value = value_to_any_value(value);
         self.record.add_attribute(key, value);
         Ok(())
     }
 }
+
+fn key_to_key(key: KeyView) -> Key {
+    Key::from(key.to_cow())
+}
+
+fn value_to_any_value(value: ValueView) -> AnyValue {
+    match value {
+        // TODO(@tisonkun): see https://github.com/open-telemetry/opentelemetry-rust/issues/3528
+        ValueView::None => AnyValue::String("null".into()),
+        ValueView::BorrowedStr(v) => AnyValue::String(v.to_string().into()),
+        ValueView::StaticStr(v) => AnyValue::String(v.into()),
+        ValueView::Char(v) => AnyValue::String(v.to_string().into()),
+        ValueView::Debug(v) => AnyValue::String(v.to_string().into()),
+        ValueView::Display(v) => AnyValue::String(v.to_string().into()),
+        ValueView::Bool(v) => AnyValue::Boolean(v),
+        ValueView::I64(v) => AnyValue::Int(v),
+        ValueView::F64(v) => AnyValue::Double(v),
+        // the following three integer transforms follow what `opentelemetry-appender-log` does:
+        // https://github.com/open-telemetry/opentelemetry-rust/blob/f7b0dd99/opentelemetry-appender-log/src/lib.rs#L259-L287
+        ValueView::U64(v) => {
+            if let Ok(i) = i64::try_from(v) {
+                AnyValue::Int(i)
+            } else {
+                AnyValue::String(v.to_string().into())
+            }
+        }
+        ValueView::I128(v) => {
+            if let Ok(i) = i64::try_from(v) {
+                AnyValue::Int(i)
+            } else {
+                AnyValue::String(v.to_string().into())
+            }
+        }
+        ValueView::U128(v) => {
+            if let Ok(i) = i64::try_from(v) {
+                AnyValue::Int(i)
+            } else {
+                AnyValue::String(v.to_string().into())
+            }
+        }
+        ValueView::List(v) => {
+            let mut l = Vec::new();
+            for item in v.iter() {
+                l.push(value_to_any_value(item));
+            }
+            AnyValue::ListAny(Box::new(l))
+        }
+        ValueView::Map(v) => {
+            let mut m = HashMap::new();
+            for (k, v) in v.iter() {
+                m.insert(key_to_key(k), value_to_any_value(v));
+            }
+            AnyValue::Map(Box::new(m))
+        }
+        v => AnyValue::String(v.to_string().into()),
+    }
+}

bridges/log/Cargo.toml

@@ -31,9 +31,16 @@ rust-version.workspace = true
 all-features = true
 rustdoc-args = ["--cfg", "docsrs"]
 
+[features]
+default = []
+serde = ["dep:serde", "log/kv_serde", "logforth-core/serde"]
+
 [dependencies]
-log = { workspace = true }
+log = { workspace = true, features = ["kv", "std"] }
 logforth-core = { workspace = true }
 
+# Optional dependencies
+serde = { workspace = true, optional = true }
+
 [lints]
 workspace = true