feat(aggregator-discovery): implement aggregator discovery in client builder

Author: jpraynaud

mithril-client/src/client.rs

@@ -2,7 +2,8 @@ use anyhow::{Context, anyhow};
 #[cfg(feature = "fs")]
 use chrono::Utc;
 use mithril_aggregator_discovery::{
-    AggregatorDiscoverer, HttpConfigAggregatorDiscoverer, MithrilNetwork,
+    AggregatorDiscoverer, CapableAggregatorDiscoverer, HttpConfigAggregatorDiscoverer,
+    MithrilNetwork,
 };
 use mithril_common::messages::AggregatorCapabilities;
 use reqwest::Url;
@@ -258,6 +259,13 @@ impl ClientBuilder {
         self
     }
 
+    /// Sets the default aggregator discoverer to use to find the aggregator endpoint when in automatic discovery.
+    pub fn with_default_aggregator_discoverer(mut self) -> ClientBuilder {
+        self.aggregator_discoverer = Some(Arc::new(HttpConfigAggregatorDiscoverer::default()));
+
+        self
+    }
+
     /// Returns a `Client` that uses the dependencies provided to this `ClientBuilder`.
     ///
     /// The builder will try to create the missing dependencies using default implementations
@@ -390,18 +398,31 @@ impl ClientBuilder {
     ) -> Result<AggregatorHTTPClient, anyhow::Error> {
         let aggregator_endpoint = match self.aggregator_discovery {
             AggregatorDiscoveryType::Url(ref url) => url.clone(),
-            AggregatorDiscoveryType::Automatic(ref network) => match &self.aggregator_discoverer {
-                Some(discoverer) => discoverer
-                    .get_available_aggregators(network.to_owned())
-                    .await
-                    .with_context(|| "Discovering aggregator endpoint failed")?
-                    .next()
-                    .unwrap()
-                    .into(),
-                None => {
-                    return Err(anyhow!("The aggregator discoverer must be provided to build the client with automatic discovery using the 'with_aggregator_discoverer' function").into());
+            AggregatorDiscoveryType::Automatic(ref network) => {
+                match self.aggregator_discoverer.clone() {
+                    Some(discoverer) => {
+                        let discoverer = if let Some(capabilities) = &self.aggregator_capabilities {
+                            Arc::new(CapableAggregatorDiscoverer::new(
+                                capabilities.to_owned(),
+                                discoverer.clone(),
+                            )) as Arc<dyn AggregatorDiscoverer>
+                        } else {
+                            discoverer as Arc<dyn AggregatorDiscoverer>
+                        };
+
+                        discoverer
+                            .get_available_aggregators(network.to_owned())
+                            .await
+                            .with_context(|| "Discovering aggregator endpoint failed")?
+                            .next()
+                            .ok_or(anyhow!("No aggregator was available through discovery"))?
+                            .into()
+                    }
+                    None => {
+                        return Err(anyhow!("The aggregator discoverer must be provided to build the client with automatic discovery using the 'with_aggregator_discoverer' function").into());
+                    }
                 }
-            },
+            }
         };
         let endpoint_url = Url::parse(&aggregator_endpoint).with_context(|| {
             format!("Invalid aggregator endpoint, it must be a correctly formed url: '{aggregator_endpoint}'")