Add http-json feature flag

opentelemetry-otlp/Cargo.toml

@@ -42,6 +42,7 @@ reqwest = { workspace = true, optional = true }
 http = { workspace = true, optional = true }
 serde = { workspace = true, features = ["derive"], optional = true }
 thiserror = { workspace = true }
+serde_json = { workspace = true, optional = true }
 
 [dev-dependencies]
 tokio-stream = { workspace = true, features = ["net"] }
@@ -58,7 +59,7 @@ metrics = ["opentelemetry/metrics", "opentelemetry_sdk/metrics", "opentelemetry-
 logs = ["opentelemetry/logs", "opentelemetry_sdk/logs", "opentelemetry-proto/logs"]
 
 # add ons
-serialize = ["serde"]
+serialize = ["serde", "serde_json"]
 
 default = ["grpc-tonic", "trace"]
 
@@ -73,6 +74,8 @@ http-proto = ["prost", "opentelemetry-http", "opentelemetry-proto/gen-tonic-mess
 reqwest-blocking-client = ["reqwest/blocking", "opentelemetry-http/reqwest"]
 reqwest-client = ["reqwest", "opentelemetry-http/reqwest"]
 reqwest-rustls = ["reqwest", "reqwest/rustls-tls-native-roots"]
+# http json
+http-json = ["serde_json", "prost", "opentelemetry-http", "opentelemetry-proto/gen-tonic-messages", "http", "trace", "metrics"]
 
 # test
 integration-testing = ["tonic", "prost", "tokio/full", "trace"]

opentelemetry-otlp/examples/basic-otlp-http/Cargo.toml

@@ -9,7 +9,7 @@ publish = false
 once_cell = { workspace = true }
 opentelemetry = { path = "../../../opentelemetry" }
 opentelemetry_sdk = { path = "../../../opentelemetry-sdk", features = ["rt-tokio", "metrics", "logs"] }
-opentelemetry-otlp = { path = "../..", features = ["http-proto", "reqwest-client", "logs"] }
+opentelemetry-otlp = { path = "../..", features = ["http-proto", "http-json", "reqwest-client", "logs"] }
 opentelemetry-appender-tracing = { path = "../../../opentelemetry-appender-tracing", default-features = false}
 opentelemetry-semantic-conventions = { path = "../../../opentelemetry-semantic-conventions" }
 

opentelemetry-otlp/src/exporter/http/mod.rs

@@ -22,7 +22,7 @@ mod logs;
 mod trace;
 
 /// Configuration of the http transport
-#[cfg(feature = "http-proto")]
+#[cfg(any(feature = "http-proto", feature = "http-json"))]
 #[derive(Debug)]
 #[cfg_attr(
     all(

opentelemetry-otlp/src/exporter/http/trace.rs

@@ -68,7 +68,7 @@ impl SpanExporter for OtlpHttpClient {
     }
 }
 
-#[cfg(feature = "http-proto")]
+#[cfg(any(feature = "http-proto", feature = "http-json"))]
 fn build_body(spans: Vec<SpanData>) -> TraceResult<(Vec<u8>, &'static str)> {
     use opentelemetry_proto::tonic::collector::trace::v1::ExportTraceServiceRequest;
     use prost::Message;
@@ -79,12 +79,12 @@ fn build_body(spans: Vec<SpanData>) -> TraceResult<(Vec<u8>, &'static str)> {
     let mut buf = vec![];
     req.encode(&mut buf).map_err(crate::Error::from)?;
 
-    Ok((buf, "application/x-protobuf"))
+    Ok((buf, "application/x-protobuf"))    
 }
 
-#[cfg(not(feature = "http-proto"))]
+#[cfg(not(any(feature = "http-proto", feature = "http-json")))]
 fn build_body(spans: Vec<SpanData>) -> TraceResult<(Vec<u8>, &'static str)> {
     Err(TraceError::Other(
-        "No http protocol configured. Enable one via `http-proto`".into(),
+        "No http protocol configured. Enable one via `http-proto` or `http-json`".into(),
     ))
 }

opentelemetry-otlp/src/exporter/mod.rs

@@ -2,7 +2,7 @@
 //!
 //! OTLP supports sending data via different protocols and formats.
 
-#[cfg(feature = "http-proto")]
+#[cfg(any(feature = "http-proto", feature = "http-json"))]
 use crate::exporter::http::HttpExporterBuilder;
 #[cfg(feature = "grpc-tonic")]
 use crate::exporter::tonic::TonicExporterBuilder;
@@ -31,15 +31,19 @@ pub const OTEL_EXPORTER_OTLP_COMPRESSION: &str = "OTEL_EXPORTER_OTLP_COMPRESSION
 #[cfg(feature = "http-proto")]
 /// Default protocol, using http-proto.
 pub const OTEL_EXPORTER_OTLP_PROTOCOL_DEFAULT: &str = OTEL_EXPORTER_OTLP_PROTOCOL_HTTP_PROTOBUF;
-#[cfg(all(feature = "grpc-tonic", not(feature = "http-proto")))]
-/// Default protocol, using grpc as http-proto feature is not enabled.
+#[cfg(all(feature = "http-json", feature = "trace", not(any(feature = "http-proto", feature = "grpc-tonic"))))]
+/// Default protocol, using http-json.
+pub const OTEL_EXPORTER_OTLP_PROTOCOL_DEFAULT: &str = OTEL_EXPORTER_OTLP_PROTOCOL_HTTP_JSON;
+#[cfg(all(feature = "grpc-tonic", not(any(feature = "http-proto", feature = "http-json"))))]
+/// Default protocol, using grpc as http-proto or http-json feature is not enabled.
 pub const OTEL_EXPORTER_OTLP_PROTOCOL_DEFAULT: &str = OTEL_EXPORTER_OTLP_PROTOCOL_GRPC;
-#[cfg(not(any(any(feature = "grpc-tonic", feature = "http-proto"))))]
+#[cfg(not(any(any(feature = "grpc-tonic", feature = "http-proto", feature = "http-json"))))]
 /// Default protocol if no features are enabled.
 pub const OTEL_EXPORTER_OTLP_PROTOCOL_DEFAULT: &str = "";
 
 const OTEL_EXPORTER_OTLP_PROTOCOL_HTTP_PROTOBUF: &str = "http/protobuf";
 const OTEL_EXPORTER_OTLP_PROTOCOL_GRPC: &str = "grpc";
+const OTEL_EXPORTER_OTLP_PROTOCOL_HTTP_JSON: &str = "http/json";
 
 /// Max waiting time for the backend to process each signal batch, defaults to 10 seconds.
 pub const OTEL_EXPORTER_OTLP_TIMEOUT: &str = "OTEL_EXPORTER_OTLP_TIMEOUT";
@@ -50,7 +54,7 @@ pub const OTEL_EXPORTER_OTLP_TIMEOUT_DEFAULT: u64 = 10;
 const OTEL_EXPORTER_OTLP_GRPC_ENDPOINT_DEFAULT: &str = "http://localhost:4317";
 const OTEL_EXPORTER_OTLP_HTTP_ENDPOINT_DEFAULT: &str = "http://localhost:4318";
 
-#[cfg(feature = "http-proto")]
+#[cfg(any(feature = "http-proto", feature = "http-json"))]
 pub(crate) mod http;
 #[cfg(feature = "grpc-tonic")]
 pub(crate) mod tonic;
@@ -112,6 +116,7 @@ fn default_protocol() -> Protocol {
     match OTEL_EXPORTER_OTLP_PROTOCOL_DEFAULT {
         OTEL_EXPORTER_OTLP_PROTOCOL_HTTP_PROTOBUF => Protocol::HttpBinary,
         OTEL_EXPORTER_OTLP_PROTOCOL_GRPC => Protocol::Grpc,
+        OTEL_EXPORTER_OTLP_PROTOCOL_HTTP_JSON => Protocol::HttpJson,
         _ => Protocol::HttpBinary,
     }
 }
@@ -121,11 +126,12 @@ fn default_endpoint(protocol: Protocol) -> String {
     match protocol {
         Protocol::Grpc => OTEL_EXPORTER_OTLP_GRPC_ENDPOINT_DEFAULT.to_string(),
         Protocol::HttpBinary => OTEL_EXPORTER_OTLP_HTTP_ENDPOINT_DEFAULT.to_string(),
+        Protocol::HttpJson => OTEL_EXPORTER_OTLP_HTTP_ENDPOINT_DEFAULT.to_string(),
     }
 }
 
 /// default user-agent headers
-#[cfg(any(feature = "grpc-tonic", feature = "http-proto"))]
+#[cfg(any(feature = "grpc-tonic", feature = "http-proto", feature = "http-json"))]
 fn default_headers() -> std::collections::HashMap<String, String> {
     let mut headers = std::collections::HashMap::new();
     headers.insert(
@@ -148,7 +154,7 @@ impl HasExportConfig for TonicExporterBuilder {
     }
 }
 
-#[cfg(feature = "http-proto")]
+#[cfg(any(feature = "http-proto", feature = "http-json"))]
 impl HasExportConfig for HttpExporterBuilder {
     fn export_config(&mut self) -> &mut ExportConfig {
         &mut self.exporter_config
@@ -210,15 +216,15 @@ impl<B: HasExportConfig> WithExportConfig for B {
     }
 }
 
-#[cfg(any(feature = "grpc-tonic", feature = "http-proto"))]
+#[cfg(any(feature = "grpc-tonic", feature = "http-proto", feature = "http-json"))]
 fn parse_header_string(value: &str) -> impl Iterator<Item = (&str, &str)> {
     value
         .split_terminator(',')
         .map(str::trim)
         .filter_map(parse_header_key_value_string)
 }
 
-#[cfg(any(feature = "grpc-tonic", feature = "http-proto"))]
+#[cfg(any(feature = "grpc-tonic", feature = "http-proto", feature = "http-json"))]
 fn parse_header_key_value_string(key_value_string: &str) -> Option<(&str, &str)> {
     key_value_string
         .split_once('=')
@@ -227,7 +233,7 @@ fn parse_header_key_value_string(key_value_string: &str) -> Option<(&str, &str)>
 }
 
 #[cfg(test)]
-#[cfg(any(feature = "grpc-tonic", feature = "http-proto"))]
+#[cfg(any(feature = "grpc-tonic", feature = "http-proto", feature = "http-json"))]
 mod tests {
 
     pub(crate) fn run_env_test<T, F>(env_vars: T, f: F)
@@ -245,7 +251,7 @@ mod tests {
         )
     }
 
-    #[cfg(feature = "http-proto")]
+    #[cfg(any(feature = "http-proto", feature = "http-json"))]
     #[test]
     fn test_default_http_endpoint() {
         let exporter_builder = crate::new_exporter().http();

opentelemetry-otlp/src/lib.rs

@@ -104,6 +104,7 @@
 //! * `reqwest-blocking-client`: Use reqwest blocking http client.
 //! * `reqwest-client`: Use reqwest http client.
 //! * `reqwest-rustls`: Use reqwest with TLS.
+//! * `http-json`: Use http as transport layer, JSON as body format.
 //!
 //! # Kitchen Sink Full Configuration
 //!
@@ -247,7 +248,7 @@ pub use crate::exporter::{
 
 use opentelemetry_sdk::export::ExportError;
 
-#[cfg(feature = "http-proto")]
+#[cfg(any(feature = "http-proto", feature = "http-json"))]
 pub use crate::exporter::http::HttpExporterBuilder;
 
 #[cfg(feature = "grpc-tonic")]
@@ -278,7 +279,7 @@ impl OtlpExporterPipeline {
     /// and build the exporter.
     ///
     /// This exporter can be used in both `tracing` and `metrics` pipeline.
-    #[cfg(feature = "http-proto")]
+    #[cfg(any(feature = "http-proto", feature = "http-json"))]
     pub fn http(self) -> HttpExporterBuilder {
         HttpExporterBuilder::default()
     }
@@ -314,7 +315,7 @@ pub enum Error {
     Transport(#[from] tonic::transport::Error),
 
     /// Wrap the [`tonic::codegen::http::uri::InvalidUri`] error
-    #[cfg(any(feature = "grpc-tonic", feature = "http-proto"))]
+    #[cfg(any(feature = "grpc-tonic", feature = "http-proto", feature = "http-json"))]
     #[error("invalid URI {0}")]
     InvalidUri(#[from] http::uri::InvalidUri),
 
@@ -329,32 +330,32 @@ pub enum Error {
     },
 
     /// Http requests failed because no http client is provided.
-    #[cfg(feature = "http-proto")]
+    #[cfg(any(feature = "http-proto", feature = "http-json"))]
     #[error(
         "no http client, you must select one from features or provide your own implementation"
     )]
     NoHttpClient,
 
     /// Http requests failed.
-    #[cfg(feature = "http-proto")]
+    #[cfg(any(feature = "http-proto", feature = "http-json"))]
     #[error("http request failed with {0}")]
     RequestFailed(#[from] opentelemetry_http::HttpError),
 
     /// The provided value is invalid in HTTP headers.
-    #[cfg(any(feature = "grpc-tonic", feature = "http-proto"))]
+    #[cfg(any(feature = "grpc-tonic", feature = "http-proto", feature = "http-json"))]
     #[error("http header value error {0}")]
     InvalidHeaderValue(#[from] http::header::InvalidHeaderValue),
 
     /// The provided name is invalid in HTTP headers.
-    #[cfg(any(feature = "grpc-tonic", feature = "http-proto"))]
+    #[cfg(any(feature = "grpc-tonic", feature = "http-proto", feature = "http-json"))]
     #[error("http header name error {0}")]
     InvalidHeaderName(#[from] http::header::InvalidHeaderName),
 
     /// Prost encode failed
-    #[cfg(feature = "http-proto")]
+    #[cfg(any(feature = "http-proto", all(feature = "http-json", not(feature = "trace"))))]
     #[error("prost encoding error {0}")]
     EncodeError(#[from] prost::EncodeError),
-
+    
     /// The lock in exporters has been poisoned.
     #[cfg(feature = "metrics")]
     #[error("the lock of the {0} has been poisoned")]
@@ -393,10 +394,10 @@ impl ExportError for Error {
 pub enum Protocol {
     /// GRPC protocol
     Grpc,
-    // TODO add support for other protocols
-    // HttpJson,
     /// HTTP protocol with binary protobuf
     HttpBinary,
+    /// HTTP protocol with JSON payload
+    HttpJson,
 }
 
 #[derive(Debug, Default)]

opentelemetry-otlp/src/span.rs

@@ -19,7 +19,7 @@ use sdk::runtime::RuntimeChannel;
 #[cfg(feature = "grpc-tonic")]
 use crate::exporter::tonic::TonicExporterBuilder;
 
-#[cfg(feature = "http-proto")]
+#[cfg(any(feature = "http-proto", feature = "http-json"))]
 use crate::exporter::http::HttpExporterBuilder;
 
 use crate::{NoExporterConfig, OtlpPipeline};
@@ -187,7 +187,7 @@ pub enum SpanExporterBuilder {
     #[cfg(feature = "grpc-tonic")]
     Tonic(TonicExporterBuilder),
     /// Http span exporter builder
-    #[cfg(feature = "http-proto")]
+    #[cfg(any(feature = "http-proto", feature = "http-json"))]
     Http(HttpExporterBuilder),
 }
 
@@ -197,7 +197,7 @@ impl SpanExporterBuilder {
         match self {
             #[cfg(feature = "grpc-tonic")]
             SpanExporterBuilder::Tonic(builder) => builder.build_span_exporter(),
-            #[cfg(feature = "http-proto")]
+            #[cfg(any(feature = "http-proto", feature = "http-json"))]
             SpanExporterBuilder::Http(builder) => builder.build_span_exporter(),
         }
     }
@@ -210,7 +210,7 @@ impl From<TonicExporterBuilder> for SpanExporterBuilder {
     }
 }
 
-#[cfg(feature = "http-proto")]
+#[cfg(any(feature = "http-proto", feature = "http-json"))]
 impl From<HttpExporterBuilder> for SpanExporterBuilder {
     fn from(exporter: HttpExporterBuilder) -> Self {
         SpanExporterBuilder::Http(exporter)