fix(proto): use camelCase for json (de)serialization. (#1462)

Part of the effort of #1327 as we need json formats for assertation in
integration tests.

## Changes

- add configuration to serde to deserialize the json in camelCase field
name
- add custom (de)serialization for traceId, spanId as they are
case-insensitive hex encoded string(see
[here](https://opentelemetry.io/docs/specs/otlp/#json-protobuf-encoding))
- add custom (de)serialization for `KeyValue`
- add tests for above, and a test using example json files

## Merge requirement checklist

* [ x]
[CONTRIBUTING](https://github.com/open-telemetry/opentelemetry-rust/blob/main/CONTRIBUTING.md)
guidelines followed
* [x] Unit tests added/updated (if applicable)
* [x] Appropriate `CHANGELOG.md` files updated for non-trivial,
user-facing changes
* [] Changes in public API reviewed (if applicable)

Author: TommyCpp

opentelemetry-proto/Cargo.toml

@@ -23,6 +23,11 @@ doctest = false
 name = "grpc_build"
 path = "tests/grpc_build.rs"
 
+[[test]]
+name = "json_deserialize"
+path = "tests/json_deserialize.rs"
+
+
 [features]
 default = []
 
@@ -42,7 +47,7 @@ zpages = ["trace"]
 
 # add ons
 with-schemars = ["schemars"]
-with-serde = ["serde"]
+with-serde = ["serde", "hex"]
 
 [dependencies]
 grpcio = { workspace = true, optional = true, features = ["prost-codec"] }
@@ -52,9 +57,11 @@ opentelemetry = { version = "0.21", default-features = false, path = "../opentel
 opentelemetry_sdk = { version = "0.21", default-features = false, path = "../opentelemetry-sdk" }
 schemars = { version = "0.8", optional = true }
 serde = { workspace = true, optional = true, features = ["serde_derive"] }
+hex = { version = "0.4.3", optional = true }
 
 [dev-dependencies]
 grpcio-compiler = { version = "0.12.1", default-features = false, features = ["prost-codec"] }
 tonic-build = { version = "0.9.0" }
 prost-build = { version = "0.11.1" }
 tempfile = "3.3.0"
+serde_json = "1.0"

opentelemetry-proto/src/proto.rs

@@ -1,3 +1,77 @@
+/// provide serde support for proto traceIds and spanIds.
+/// Those are hex encoded strings in the jsons but they are byte arrays in the proto.
+/// See https://opentelemetry.io/docs/specs/otlp/#json-protobuf-encoding for more details
+#[cfg(all(feature = "with-serde", feature = "gen-tonic-messages"))]
+pub(crate) mod serializers {
+    use crate::tonic::common::v1::any_value::Value;
+    use crate::tonic::common::v1::AnyValue;
+    use serde::de::{self, MapAccess, Visitor};
+    use serde::ser::SerializeStruct;
+    use serde::{Deserialize, Deserializer, Serialize, Serializer};
+    use std::fmt;
+
+    // hex string <-> bytes conversion
+
+    pub fn serialize_to_hex_string<S>(bytes: &[u8], serializer: S) -> Result<S::Ok, S::Error>
+    where
+        S: Serializer,
+    {
+        let hex_string = hex::encode(bytes);
+        serializer.serialize_str(&hex_string)
+    }
+
+    pub fn deserialize_from_hex_string<'de, D>(deserializer: D) -> Result<Vec<u8>, D::Error>
+    where
+        D: Deserializer<'de>,
+    {
+        struct BytesVisitor;
+
+        impl<'de> Visitor<'de> for BytesVisitor {
+            type Value = Vec<u8>;
+
+            fn expecting(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
+                formatter.write_str("a string representing hex-encoded bytes")
+            }
+
+            fn visit_str<E>(self, value: &str) -> Result<Vec<u8>, E>
+            where
+                E: de::Error,
+            {
+                hex::decode(value).map_err(E::custom)
+            }
+        }
+
+        deserializer.deserialize_str(BytesVisitor)
+    }
+
+    // AnyValue <-> KeyValue conversion
+    pub fn serialize_to_value<S>(value: &Option<AnyValue>, serializer: S) -> Result<S::Ok, S::Error>
+        where
+            S: Serializer,
+    {
+        // Serialize any_value::Value using its own implementation
+        // If value is None, it will be serialized as such
+        match value {
+            Some(value) => value.value.serialize(serializer),
+            None => serializer.serialize_none(),
+        }
+
+    }
+
+    pub fn deserialize_from_value<'de, D>(deserializer: D) -> Result<Option<AnyValue>, D::Error>
+    where
+        D: Deserializer<'de>,
+    {
+        // Deserialize any_value::Value using its own implementation
+        let value = Option::<Value>::deserialize(deserializer)?;
+
+        // Wrap the deserialized value in AnyValue
+        Ok(Some(AnyValue { value }))
+    }
+
+
+}
+
 #[cfg(feature = "gen-tonic-messages")]
 #[path = "proto/tonic"]
 /// Generated files using [`tonic`](https://docs.rs/crate/tonic) and [`prost`](https://docs.rs/crate/prost)

opentelemetry-proto/src/proto/tonic/opentelemetry.proto.collector.logs.v1.rs

@@ -1,5 +1,6 @@
 #[cfg_attr(feature = "with-schemars", derive(schemars::JsonSchema))]
 #[cfg_attr(feature = "with-serde", derive(serde::Serialize, serde::Deserialize))]
+#[cfg_attr(feature = "with-serde", serde(rename_all = "camelCase"))]
 #[allow(clippy::derive_partial_eq_without_eq)]
 #[derive(Clone, PartialEq, ::prost::Message)]
 pub struct ExportLogsServiceRequest {
@@ -15,6 +16,7 @@ pub struct ExportLogsServiceRequest {
 }
 #[cfg_attr(feature = "with-schemars", derive(schemars::JsonSchema))]
 #[cfg_attr(feature = "with-serde", derive(serde::Serialize, serde::Deserialize))]
+#[cfg_attr(feature = "with-serde", serde(rename_all = "camelCase"))]
 #[allow(clippy::derive_partial_eq_without_eq)]
 #[derive(Clone, PartialEq, ::prost::Message)]
 pub struct ExportLogsServiceResponse {
@@ -38,6 +40,7 @@ pub struct ExportLogsServiceResponse {
 }
 #[cfg_attr(feature = "with-schemars", derive(schemars::JsonSchema))]
 #[cfg_attr(feature = "with-serde", derive(serde::Serialize, serde::Deserialize))]
+#[cfg_attr(feature = "with-serde", serde(rename_all = "camelCase"))]
 #[allow(clippy::derive_partial_eq_without_eq)]
 #[derive(Clone, PartialEq, ::prost::Message)]
 pub struct ExportLogsPartialSuccess {

opentelemetry-proto/src/proto/tonic/opentelemetry.proto.collector.metrics.v1.rs

@@ -1,5 +1,6 @@
 #[cfg_attr(feature = "with-schemars", derive(schemars::JsonSchema))]
 #[cfg_attr(feature = "with-serde", derive(serde::Serialize, serde::Deserialize))]
+#[cfg_attr(feature = "with-serde", serde(rename_all = "camelCase"))]
 #[allow(clippy::derive_partial_eq_without_eq)]
 #[derive(Clone, PartialEq, ::prost::Message)]
 pub struct ExportMetricsServiceRequest {
@@ -15,6 +16,7 @@ pub struct ExportMetricsServiceRequest {
 }
 #[cfg_attr(feature = "with-schemars", derive(schemars::JsonSchema))]
 #[cfg_attr(feature = "with-serde", derive(serde::Serialize, serde::Deserialize))]
+#[cfg_attr(feature = "with-serde", serde(rename_all = "camelCase"))]
 #[allow(clippy::derive_partial_eq_without_eq)]
 #[derive(Clone, PartialEq, ::prost::Message)]
 pub struct ExportMetricsServiceResponse {
@@ -38,6 +40,7 @@ pub struct ExportMetricsServiceResponse {
 }
 #[cfg_attr(feature = "with-schemars", derive(schemars::JsonSchema))]
 #[cfg_attr(feature = "with-serde", derive(serde::Serialize, serde::Deserialize))]
+#[cfg_attr(feature = "with-serde", serde(rename_all = "camelCase"))]
 #[allow(clippy::derive_partial_eq_without_eq)]
 #[derive(Clone, PartialEq, ::prost::Message)]
 pub struct ExportMetricsPartialSuccess {

opentelemetry-proto/src/proto/tonic/opentelemetry.proto.collector.trace.v1.rs

@@ -1,5 +1,6 @@
 #[cfg_attr(feature = "with-schemars", derive(schemars::JsonSchema))]
 #[cfg_attr(feature = "with-serde", derive(serde::Serialize, serde::Deserialize))]
+#[cfg_attr(feature = "with-serde", serde(rename_all = "camelCase"))]
 #[allow(clippy::derive_partial_eq_without_eq)]
 #[derive(Clone, PartialEq, ::prost::Message)]
 pub struct ExportTraceServiceRequest {
@@ -15,6 +16,7 @@ pub struct ExportTraceServiceRequest {
 }
 #[cfg_attr(feature = "with-schemars", derive(schemars::JsonSchema))]
 #[cfg_attr(feature = "with-serde", derive(serde::Serialize, serde::Deserialize))]
+#[cfg_attr(feature = "with-serde", serde(rename_all = "camelCase"))]
 #[allow(clippy::derive_partial_eq_without_eq)]
 #[derive(Clone, PartialEq, ::prost::Message)]
 pub struct ExportTraceServiceResponse {
@@ -38,6 +40,7 @@ pub struct ExportTraceServiceResponse {
 }
 #[cfg_attr(feature = "with-schemars", derive(schemars::JsonSchema))]
 #[cfg_attr(feature = "with-serde", derive(serde::Serialize, serde::Deserialize))]
+#[cfg_attr(feature = "with-serde", serde(rename_all = "camelCase"))]
 #[allow(clippy::derive_partial_eq_without_eq)]
 #[derive(Clone, PartialEq, ::prost::Message)]
 pub struct ExportTracePartialSuccess {

opentelemetry-proto/src/proto/tonic/opentelemetry.proto.common.v1.rs

@@ -3,6 +3,7 @@
 /// object containing arrays, key-value lists and primitives.
 #[cfg_attr(feature = "with-schemars", derive(schemars::JsonSchema))]
 #[cfg_attr(feature = "with-serde", derive(serde::Serialize, serde::Deserialize))]
+#[cfg_attr(feature = "with-serde", serde(rename_all = "camelCase"))]
 #[allow(clippy::derive_partial_eq_without_eq)]
 #[derive(Clone, PartialEq, ::prost::Message)]
 pub struct AnyValue {
@@ -17,6 +18,7 @@ pub mod any_value {
     /// in which case this AnyValue is considered to be "empty".
     #[cfg_attr(feature = "with-schemars", derive(schemars::JsonSchema))]
     #[cfg_attr(feature = "with-serde", derive(serde::Serialize, serde::Deserialize))]
+    #[cfg_attr(feature = "with-serde", serde(rename_all = "camelCase"))]
     #[allow(clippy::derive_partial_eq_without_eq)]
     #[derive(Clone, PartialEq, ::prost::Oneof)]
     pub enum Value {
@@ -40,6 +42,7 @@ pub mod any_value {
 /// since oneof in AnyValue does not allow repeated fields.
 #[cfg_attr(feature = "with-schemars", derive(schemars::JsonSchema))]
 #[cfg_attr(feature = "with-serde", derive(serde::Serialize, serde::Deserialize))]
+#[cfg_attr(feature = "with-serde", serde(rename_all = "camelCase"))]
 #[allow(clippy::derive_partial_eq_without_eq)]
 #[derive(Clone, PartialEq, ::prost::Message)]
 pub struct ArrayValue {
@@ -54,6 +57,7 @@ pub struct ArrayValue {
 /// are semantically equivalent.
 #[cfg_attr(feature = "with-schemars", derive(schemars::JsonSchema))]
 #[cfg_attr(feature = "with-serde", derive(serde::Serialize, serde::Deserialize))]
+#[cfg_attr(feature = "with-serde", serde(rename_all = "camelCase"))]
 #[allow(clippy::derive_partial_eq_without_eq)]
 #[derive(Clone, PartialEq, ::prost::Message)]
 pub struct KeyValueList {
@@ -68,18 +72,28 @@ pub struct KeyValueList {
 /// attributes, etc.
 #[cfg_attr(feature = "with-schemars", derive(schemars::JsonSchema))]
 #[cfg_attr(feature = "with-serde", derive(serde::Serialize, serde::Deserialize))]
+#[cfg_attr(feature = "with-serde", serde(rename_all = "camelCase"))]
 #[allow(clippy::derive_partial_eq_without_eq)]
 #[derive(Clone, PartialEq, ::prost::Message)]
 pub struct KeyValue {
     #[prost(string, tag = "1")]
     pub key: ::prost::alloc::string::String,
     #[prost(message, optional, tag = "2")]
+    #[cfg_attr(
+        feature = "with-serde",
+        serde(
+            serialize_with = "crate::proto::serializers::serialize_to_value",
+            deserialize_with = "crate::proto::serializers::deserialize_from_value"
+        )
+    )]
     pub value: ::core::option::Option<AnyValue>,
 }
 /// InstrumentationScope is a message representing the instrumentation scope information
 /// such as the fully qualified name and version.
 #[cfg_attr(feature = "with-schemars", derive(schemars::JsonSchema))]
 #[cfg_attr(feature = "with-serde", derive(serde::Serialize, serde::Deserialize))]
+#[cfg_attr(feature = "with-serde", serde(rename_all = "camelCase"))]
+#[cfg_attr(feature = "with-serde", serde(default))]
 #[allow(clippy::derive_partial_eq_without_eq)]
 #[derive(Clone, PartialEq, ::prost::Message)]
 pub struct InstrumentationScope {

opentelemetry-proto/src/proto/tonic/opentelemetry.proto.logs.v1.rs

@@ -10,6 +10,7 @@
 /// as well.
 #[cfg_attr(feature = "with-schemars", derive(schemars::JsonSchema))]
 #[cfg_attr(feature = "with-serde", derive(serde::Serialize, serde::Deserialize))]
+#[cfg_attr(feature = "with-serde", serde(rename_all = "camelCase"))]
 #[allow(clippy::derive_partial_eq_without_eq)]
 #[derive(Clone, PartialEq, ::prost::Message)]
 pub struct LogsData {
@@ -24,6 +25,7 @@ pub struct LogsData {
 /// A collection of ScopeLogs from a Resource.
 #[cfg_attr(feature = "with-schemars", derive(schemars::JsonSchema))]
 #[cfg_attr(feature = "with-serde", derive(serde::Serialize, serde::Deserialize))]
+#[cfg_attr(feature = "with-serde", serde(rename_all = "camelCase"))]
 #[allow(clippy::derive_partial_eq_without_eq)]
 #[derive(Clone, PartialEq, ::prost::Message)]
 pub struct ResourceLogs {
@@ -42,6 +44,7 @@ pub struct ResourceLogs {
 /// A collection of Logs produced by a Scope.
 #[cfg_attr(feature = "with-schemars", derive(schemars::JsonSchema))]
 #[cfg_attr(feature = "with-serde", derive(serde::Serialize, serde::Deserialize))]
+#[cfg_attr(feature = "with-serde", serde(rename_all = "camelCase"))]
 #[allow(clippy::derive_partial_eq_without_eq)]
 #[derive(Clone, PartialEq, ::prost::Message)]
 pub struct ScopeLogs {
@@ -61,6 +64,7 @@ pub struct ScopeLogs {
 /// <https://github.com/open-telemetry/oteps/blob/main/text/logs/0097-log-data-model.md>
 #[cfg_attr(feature = "with-schemars", derive(schemars::JsonSchema))]
 #[cfg_attr(feature = "with-serde", derive(serde::Serialize, serde::Deserialize))]
+#[cfg_attr(feature = "with-serde", serde(rename_all = "camelCase"))]
 #[allow(clippy::derive_partial_eq_without_eq)]
 #[derive(Clone, PartialEq, ::prost::Message)]
 pub struct LogRecord {
@@ -144,6 +148,7 @@ pub struct LogRecord {
 /// Possible values for LogRecord.SeverityNumber.
 #[cfg_attr(feature = "with-schemars", derive(schemars::JsonSchema))]
 #[cfg_attr(feature = "with-serde", derive(serde::Serialize, serde::Deserialize))]
+#[cfg_attr(feature = "with-serde", serde(rename_all = "camelCase"))]
 #[derive(Clone, Copy, Debug, PartialEq, Eq, Hash, PartialOrd, Ord, ::prost::Enumeration)]
 #[repr(i32)]
 pub enum SeverityNumber {
@@ -248,6 +253,7 @@ impl SeverityNumber {
 ///
 #[cfg_attr(feature = "with-schemars", derive(schemars::JsonSchema))]
 #[cfg_attr(feature = "with-serde", derive(serde::Serialize, serde::Deserialize))]
+#[cfg_attr(feature = "with-serde", serde(rename_all = "camelCase"))]
 #[derive(Clone, Copy, Debug, PartialEq, Eq, Hash, PartialOrd, Ord, ::prost::Enumeration)]
 #[repr(i32)]
 pub enum LogRecordFlags {