feat(mux): add HTTP source in loader (#255)

Author: kamsz

config.example.toml

@@ -120,6 +120,13 @@ validator_pubkeys = [
 #   - SSV: SSV API
 # OPTIONAL
 loader = "./tests/data/mux_keys.example.json"
+# URL to HTTP endpoint returning JSON list of validator pubkeys
+# Example response:
+# [
+#   "0x80c7f782b2467c5898c5516a8b6595d75623960b4afc4f71ee07d40985d20e117ba35e7cd352a3e75fb85a8668a3b745",
+#   "0xa119589bb33ef52acbb8116832bec2b58fca590fe5c85eac5d3230b44d5bc09fe73ccd21f88eab31d6de16194d17782e"
+#]
+# loader = { url = "http://localhost:8000/keys" }
 # loader = { registry = "lido", node_operator_id = 8 }
 # loader = { registry = "ssv", node_operator_id = 8 }
 timeout_get_header_ms = 900

crates/common/src/config/mux.rs

@@ -129,6 +129,7 @@ impl MuxConfig {
 
                 Some((get_mux_env(&self.id), path.to_owned(), internal_path))
             }
+            MuxKeysLoader::HTTP { .. } => None,
             MuxKeysLoader::Registry { .. } => None,
         })
     }
@@ -139,6 +140,9 @@ impl MuxConfig {
 pub enum MuxKeysLoader {
     /// A file containing a list of validator pubkeys
     File(PathBuf),
+    HTTP {
+        url: String,
+    },
     Registry {
         registry: NORegistry,
         node_operator_id: u64,
@@ -170,6 +174,14 @@ impl MuxKeysLoader {
                 serde_json::from_str(&file).wrap_err("failed to parse mux keys file")
             }
 
+            Self::HTTP { url } => {
+                let client = reqwest::Client::new();
+                let response = client.get(url).send().await?;
+                let pubkeys = response.text().await?;
+                serde_json::from_str(&pubkeys)
+                    .wrap_err("failed to fetch mux keys from http endpoint")
+            }
+
             Self::Registry { registry, node_operator_id } => match registry {
                 NORegistry::Lido => {
                     let Some(rpc_url) = rpc_url else {