remove grpcio

We do not need to use two different gRPC implementations for OTLP, and
grpcio greatly increases the compilation times and CI cache size, so
we're choosing to use tonic instead

* make the OTLP exporters non exclusive

We should be able to build a router with both OTLP/HTTP and OTLP/gRPC
exporters

update the opentelemetry dependency to get access to
SpanExporterBuilder that was not public before

.circleci/config.yml

@@ -144,16 +144,6 @@ commands:
 
   windows_prepare_rust_env:
     steps:
-      #            - run:
-      #                # TODO compiling grpcio on Windows is still not working
-      #                #      using boringssl gives an error message
-      #                #      using openssl hangs indefinitely
-      #                name: Install grpcio build dependencies
-      #                command: |
-      #                  choco install activeperl -y
-      #                  choco install cmake -y --installargs 'ADD_CMAKE_TO_PATH=System'
-      #                  choco install yasm -y
-      #                  choco install openssl -y
       - run:
           name: Install rustup
           environment:
@@ -255,7 +245,7 @@ commands:
       - build_common_permutations
       - rust/build:
           with_cache: false
-          crate: --no-default-features --features otlp-grpcio -p apollo-router -p apollo-router-core
+          crate: --no-default-features -p apollo-router -p apollo-router-core
   build_workspace:
     parameters:
       os:

Cargo.toml

@@ -3,5 +3,5 @@ default-members = ["crates/apollo-router", "crates/apollo-router-core"]
 members = ["crates/apollo-router", "crates/apollo-router-core", "xtask"]
 
 [patch.crates-io]
-opentelemetry = { git = "https://github.com/open-telemetry/opentelemetry-rust.git", rev = "414b3f459" }
-opentelemetry-otlp = { git = "https://github.com/open-telemetry/opentelemetry-rust.git", rev = "414b3f459" }
+opentelemetry = { git = "https://github.com/open-telemetry/opentelemetry-rust.git", rev = "6b3aa02aa" }
+opentelemetry-otlp = { git = "https://github.com/open-telemetry/opentelemetry-rust.git", rev = "6b3aa02aa" }

crates/apollo-router/Cargo.toml

@@ -10,14 +10,13 @@ name = "router"
 path = "src/main.rs"
 
 [features]
-default = ["otlp-tonic"]
-otlp-tonic = [
+default = ["otlp-grpc"]
+otlp-grpc = [
     "opentelemetry-otlp/tonic",
     "opentelemetry-otlp/tonic-build",
     "opentelemetry-otlp/prost",
     "tonic",
 ]
-otlp-grpcio = ["opentelemetry-otlp/grpc-sys", "opentelemetry-otlp/openssl"]
 otlp-http = ["opentelemetry-otlp/http-proto"]
 tls = ["opentelemetry-otlp/tls", "tonic/transport", "tonic/tls"]
 

crates/apollo-router/src/configuration/mod.rs

@@ -1,15 +1,6 @@
 //! Logic for loading configuration in to an object model
 
-#[cfg(any(
-    all(
-        feature = "otlp-tonic",
-        any(feature = "otlp-grpcio", feature = "otlp-http")
-    ),
-    all(feature = "otlp-grpcio", feature = "otlp-http")
-))]
-compile_error!("you can select only one feature otlp-*!");
-
-#[cfg(any(feature = "otlp-tonic", feature = "otlp-grpcio", feature = "otlp-http"))]
+#[cfg(any(feature = "otlp-tonic", feature = "otlp-http"))]
 pub mod otlp;
 
 use apollo_router_core::prelude::*;
@@ -32,6 +23,10 @@ pub enum ConfigurationError {
     CannotReadSecretFromFile(std::io::Error),
     /// Could not read secret from environment variable: {0}
     CannotReadSecretFromEnv(std::env::VarError),
+    /// Missing environment variable: {0}
+    MissingEnvironmentVariable(String),
+    /// Invalid environment variable: {0}
+    InvalidEnvironmentVariable(String),
     /// Could not setup OTLP tracing: {0}
     OtlpTracing(opentelemetry::trace::TraceError),
     /// The configuration could not be loaded because it requires the feature {0:?}
@@ -204,7 +199,7 @@ impl Cors {
 #[allow(clippy::large_enum_variant)]
 pub enum OpenTelemetry {
     Jaeger(Option<Jaeger>),
-    #[cfg(any(feature = "otlp-tonic", feature = "otlp-grpcio", feature = "otlp-http"))]
+    #[cfg(any(feature = "otlp-tonic", feature = "otlp-http"))]
     Otlp(otlp::Otlp),
 }
 
@@ -317,13 +312,21 @@ mod tests {
         assert_config_snapshot!("testdata/config_opentelemetry_jaeger_full.yml");
     }
 
-    #[cfg(any(feature = "otlp-tonic", feature = "otlp-grpcio", feature = "otlp-http"))]
+    #[cfg(any(feature = "otlp-tonic", feature = "otlp-http"))]
     #[test]
     fn ensure_configuration_api_does_not_change_common() {
         // NOTE: don't take a snapshot here because the optional fields appear with ~ and they vary
         // per implementation
+
+        #[cfg(feature = "otlp-http")]
+        serde_yaml::from_str::<Configuration>(include_str!(
+            "testdata/config_opentelemetry_otlp_tracing_http_common.yml"
+        ))
+        .unwrap();
+
+        #[cfg(feature = "otlp-tonic")]
         serde_yaml::from_str::<Configuration>(include_str!(
-            "testdata/config_opentelemetry_otlp_tracing_common.yml"
+            "testdata/config_opentelemetry_otlp_tracing_tonic_common.yml"
         ))
         .unwrap();
     }
@@ -335,13 +338,6 @@ mod tests {
         assert_config_snapshot!("testdata/config_opentelemetry_otlp_tracing_tonic_full.yml");
     }
 
-    #[cfg(feature = "otlp-grpcio")]
-    #[test]
-    fn ensure_configuration_api_does_not_change_grpcio() {
-        assert_config_snapshot!("testdata/config_opentelemetry_otlp_tracing_grpcio_basic.yml");
-        assert_config_snapshot!("testdata/config_opentelemetry_otlp_tracing_grpcio_full.yml");
-    }
-
     #[cfg(feature = "otlp-http")]
     #[test]
     fn ensure_configuration_api_does_not_change_http() {
@@ -352,7 +348,7 @@ mod tests {
     #[cfg(all(feature = "tls", feature = "otlp-tonic"))]
     #[test]
     fn ensure_configuration_api_does_not_change_tls_config() {
-        assert_config_snapshot!("testdata/config_opentelemetry_otlp_tls.yml");
+        assert_config_snapshot!("testdata/config_opentelemetry_otlp_tracing_tonic_tls.yml");
     }
 
     #[test]