feat(pegboard): add support for custom host entries

packages/edge/infra/client/config/src/manager.rs

@@ -101,6 +101,10 @@ pub struct Runner {
 
 	pub container_runner_binary_path: Option<PathBuf>,
 	pub isolate_runner_binary_path: Option<PathBuf>,
+
+	/// Custom host entries to append to /etc/hosts in actor containers.
+	#[serde(default)]
+	pub custom_hosts: Option<Vec<HostEntry>>,
 }
 
 impl Runner {
@@ -127,6 +131,10 @@ impl Runner {
 			.clone()
 			.unwrap_or_else(|| Path::new("/usr/local/bin/rivet-isolate-v8-runner").into())
 	}
+
+	pub fn custom_hosts(&self) -> &[HostEntry] {
+		self.custom_hosts.as_deref().unwrap_or(&[])
+	}
 }
 
 #[derive(Clone, Deserialize, JsonSchema, Default)]
@@ -292,3 +300,10 @@ pub enum Addresses {
 pub struct Vector {
 	pub address: String,
 }
+
+#[derive(Clone, Deserialize, JsonSchema)]
+#[serde(rename_all = "snake_case", deny_unknown_fields)]
+pub struct HostEntry {
+	pub ip: String,
+	pub hostname: String,
+}

packages/edge/infra/client/manager/src/actor/setup.rs

@@ -242,12 +242,7 @@ impl Actor {
 		);
 
 		// hosts file content
-		let hosts_content = indoc!(
-			"
-			127.0.0.1	localhost
-			::1			localhost ip6-localhost ip6-loopback
-			"
-		);
+		let hosts_content = build_hosts_content(ctx);
 
 		// Write all files in parallel
 		tracing::info!(
@@ -775,6 +770,21 @@ impl Actor {
 	}
 }
 
+fn build_hosts_content(ctx: &Ctx) -> String {
+	let mut content = indoc!(
+		"
+		127.0.0.1	localhost
+		::1			localhost ip6-localhost ip6-loopback
+		"
+	).to_string();
+
+	for host_entry in ctx.config().runner.custom_hosts() {
+		content.push_str(&format!("{}\t{}\n", host_entry.ip, host_entry.hostname));
+	}
+
+	content
+}
+
 async fn bind_ports_inner(
 	ctx: &Ctx,
 	actor_id: Uuid,