Add config for advertised address to GRPC proxy (#79)

* add advertised config address

* updated docs

* fmt

* minor update

provider_proxies/grpc/v1/README.md

@@ -1,12 +1,13 @@
-# GRPC Provider Proxy
+# gRPC Provider Proxy
 
-The GRPC Provider Proxy interfaces with providers which support GRPC. It acts as a consumer for digital twin providers. This proxy supports the `Get` and `Subscribe` operations as defined for the [Ibeji mixed sample](https://github.com/eclipse-ibeji/ibeji/tree/main/samples/mixed). To use this proxy with other providers, those providers will need to support the same API(s) as the provider in that sample (see [Integrating with this Proxy](#integrating-with-this-proxy) for more information).
+The gRPC Provider Proxy interfaces with providers which support gRPC. It acts as a consumer for digital twin providers. This proxy supports the `Get` and `Subscribe` operations as defined for the [Ibeji mixed sample](https://github.com/eclipse-ibeji/ibeji/tree/main/samples/mixed). To use this proxy with other providers, those providers will need to support the same API(s) as the provider in that sample (see [Integrating with this Proxy](#integrating-with-this-proxy) for more information).
 
 ## Configuration
 
 This proxy supports the following configuration settings:
 
-- `consumer_address`: The address for the proxy's consumer
+- `consumer_address`: The address for the proxy's consumer. The proxy's gRPC server will be hosted on this address.
+- `advertised_consumer_address`: (Optional) The advertised address for the proxy's consumer. This is the address that will be reported as the callback address to providers, enabling scenarios where the providers should use a different address from the actual hosting address. If not specified, this proxy will default to using the consumer address.
 
 This adapter supports [config overrides](../../../docs/config-overrides.md). The override filename is `grpc_proxy_config.json`, and the default config is located at `res/grpc_proxy_config.default.json`.
 

provider_proxies/grpc/v1/src/config.rs

@@ -7,6 +7,21 @@ use serde::{Deserialize, Serialize};
 /// The GRPC provider proxy config
 #[derive(Clone, Debug, Serialize, Deserialize)]
 pub struct Config {
-    /// The set of config values
+    /// The hosting address
     pub consumer_address: String,
+
+    /// The advertised address given to providers as the callback address
+    /// If not specified, the `consumer_address` will be used
+    pub advertised_consumer_address: Option<String>,
+}
+
+impl Config {
+    /// Gets the advertised address.
+    /// Returns the value of `self.advertised_consumer_address` if it's not `None`,
+    /// otherwise returns `self.consumer_address`.
+    pub fn get_advertised_address(&self) -> &String {
+        self.advertised_consumer_address
+            .as_ref()
+            .unwrap_or(&self.consumer_address)
+    }
 }

provider_proxies/grpc/v1/src/grpc_provider_proxy.rs

@@ -109,7 +109,7 @@ impl ProviderProxy for GRPCProviderProxy {
     /// # Arguments
     /// - `entity_id`: the entity id that needs a value
     async fn send_request_to_provider(&self, entity_id: &str) -> Result<(), ProviderProxyError> {
-        let consumer_uri = format!("http://{}", self.config.consumer_address); // Devskim: ignore DS137138
+        let consumer_uri = format!("http://{}", self.config.get_advertised_address()); // Devskim: ignore DS137138
 
         let operation_result;
         {
@@ -174,7 +174,7 @@ impl ProviderProxy for GRPCProviderProxy {
             .insert(String::from(entity_id), String::from(selected_operation));
 
         if selected_operation == SUBSCRIBE_OPERATION {
-            let consumer_uri = format!("http://{}", self.config.consumer_address); // Devskim: ignore DS137138
+            let consumer_uri = format!("http://{}", self.config.get_advertised_address()); // Devskim: ignore DS137138
             let mut client = self.provider_client.clone();
             let request = tonic::Request::new(SubscribeRequest {
                 entity_id: String::from(entity_id),
@@ -323,6 +323,7 @@ mod grpc_provider_proxy_v1_tests {
                 let grpc_provider_proxy = GRPCProviderProxy {
                     config: Config {
                         consumer_address: "[::1]:60010".to_string(),
+                        advertised_consumer_address: None,
                     },
                     provider_client: client,
                     entity_operation_map: Mutex::new(HashMap::new()),