Default init seed nodes based on network choice

And more flushed out but incomplete

zebra-network/src/config.rs

@@ -1,4 +1,7 @@
-use std::{net::SocketAddr, time::Duration};
+use std::{
+    net::{SocketAddr, ToSocketAddrs},
+    time::Duration,
+};
 
 use crate::network::Network;
 
@@ -8,29 +11,59 @@ use crate::network::Network;
 pub struct Config {
     /// The address on which this node should listen for connections.
     pub listen_addr: SocketAddr,
+
     /// The network to connect to.
     pub network: Network,
+
     /// The user-agent to advertise.
     pub user_agent: String,
-    /// A list of initial peers for the peerset.
+
+    /// A list of initial peers for the peerset when operating on
+    /// mainnet.
     ///
     /// XXX this should be replaced with DNS names, not SocketAddrs
-    pub initial_peers: Vec<SocketAddr>,
+    pub initial_mainnet_peers: Vec<SocketAddr>,
+
+    /// A list of initial peers for the peerset when operating on
+    /// testnet.
+    pub initial_testnet_peers: Vec<SocketAddr>,
+
     /// The outgoing request buffer size for the peer set.
     pub peerset_request_buffer_size: usize,
 
     // Note: due to the way this is rendered by the toml
     // serializer, the Duration fields should come last.
     /// The default RTT estimate for peer responses, used in load-balancing.
     pub ewma_default_rtt: Duration,
+
     /// The decay time for the exponentially-weighted moving average response time.
     pub ewma_decay_time: Duration,
+
     /// The timeout for peer handshakes.
     pub handshake_timeout: Duration,
+
     /// How frequently we attempt to connect to a new peer.
     pub new_peer_interval: Duration,
 }
 
+impl Config {
+    fn parse_peers<S: ToSocketAddrs>(peers: Vec<S>) -> Vec<SocketAddr> {
+        peers
+            .iter()
+            .flat_map(|s| s.to_socket_addrs())
+            .flatten()
+            .collect::<Vec<SocketAddr>>()
+    }
+
+    /// Get the initial seed peers based on the configured network.
+    pub fn initial_peers(&self) -> Vec<SocketAddr> {
+        match self.network {
+            Network::Mainnet => self.initial_mainnet_peers.clone(),
+            Network::Testnet => self.initial_testnet_peers.clone(),
+        }
+    }
+}
+
 impl Default for Config {
     fn default() -> Config {
         Config {
@@ -39,7 +72,12 @@ impl Default for Config {
                 .expect("Hardcoded address should be parseable"),
             user_agent: crate::constants::USER_AGENT.to_owned(),
             network: Network::Mainnet,
-            initial_peers: Vec::new(),
+            initial_mainnet_peers: Config::parse_peers(vec![
+                "dnsseed.z.cash:8233",
+                "dnsseed.str4d.xyz:8233",
+                "dnsseed.znodes.org:8233",
+            ]),
+            initial_testnet_peers: Config::parse_peers(vec!["dnsseed.testnet.z.cash:18233"]),
             ewma_default_rtt: Duration::from_secs(1),
             ewma_decay_time: Duration::from_secs(60),
             peerset_request_buffer_size: 1,

zebra-network/src/peer_set.rs

@@ -103,7 +103,7 @@ where
 
     // 1. Initial peers, specified in the config.
     tokio::spawn(add_initial_peers(
-        config.initial_peers.clone(),
+        config.initial_peers(),
         connector.clone(),
         peerset_tx.clone(),
     ));

zebrad/src/commands.rs

@@ -12,10 +12,13 @@
 
 mod config;
 mod connect;
+mod seed;
 mod start;
 mod version;
 
-use self::{config::ConfigCmd, connect::ConnectCmd, start::StartCmd, version::VersionCmd};
+use self::{
+    config::ConfigCmd, connect::ConnectCmd, seed::SeedCmd, start::StartCmd, version::VersionCmd,
+};
 use crate::config::ZebradConfig;
 use abscissa_core::{
     config::Override, Command, Configurable, FrameworkError, Help, Options, Runnable,
@@ -47,6 +50,10 @@ pub enum ZebradCmd {
     /// The `connect` subcommand
     #[options(help = "testing stub for dumping network messages")]
     Connect(ConnectCmd),
+
+    /// The `seed` subcommand
+    #[options(help = "dns seeder")]
+    Seed(SeedCmd),
 }
 
 /// This trait allows you to define how application configuration is loaded.

zebrad/src/commands/connect.rs

@@ -66,9 +66,7 @@ impl ConnectCmd {
             1,
         );
 
-        let mut config = app_config().network.clone();
-
-        config.initial_peers = vec![self.addr];
+        let config = app_config().network.clone();
 
         let (mut peer_set, address_book) = zebra_network::init(config, node).await;
 

zebrad/src/commands/seed.rs

@@ -0,0 +1,99 @@
+//! `seed` subcommand - test stub for talking to zcashd
+
+use crate::{config::ZebradConfig, prelude::*};
+
+use abscissa_core::{config, Command, FrameworkError, Options, Runnable};
+
+/// `seed` subcommand
+///
+/// A DNS seeder command to spider and collect as many valid peer
+/// addresses as we can.
+#[derive(Command, Debug, Options)]
+pub struct SeedCmd {
+    /// Filter strings
+    #[options(free)]
+    filters: Vec<String>,
+}
+
+impl config::Override<ZebradConfig> for SeedCmd {
+    // Process the given command line options, overriding settings
+    // from a configuration file using explicit flags taken from
+    // command-line arguments.
+    fn override_config(&self, mut config: ZebradConfig) -> Result<ZebradConfig, FrameworkError> {
+        if !self.filters.is_empty() {
+            config.tracing.filter = self.filters.join(",");
+        }
+
+        Ok(config)
+    }
+}
+
+impl Runnable for SeedCmd {
+    /// Start the application.
+    fn run(&self) {
+        use crate::components::tokio::TokioComponent;
+
+        let wait = tokio::future::pending::<()>();
+        // Combine the seed future with an infinite wait
+        // so that the program has to be explicitly killed and
+        // won't die before all tracing messages are written.
+        let fut = futures::future::join(
+            async {
+                match self.seed().await {
+                    Ok(()) => {}
+                    Err(e) => {
+                        // Print any error that occurs.
+                        error!(?e);
+                    }
+                }
+            },
+            wait,
+        );
+
+        let _ = app_reader()
+            .state()
+            .components
+            .get_downcast_ref::<TokioComponent>()
+            .expect("TokioComponent should be available")
+            .rt
+            .block_on(fut);
+    }
+}
+
+impl SeedCmd {
+    async fn seed(&self) -> Result<(), failure::Error> {
+        use failure::Error;
+        use futures::stream::{FuturesUnordered, StreamExt};
+        use tower::{buffer::Buffer, service_fn, Service, ServiceExt};
+        use zebra_network::{AddressBook, Request, Response};
+
+        info!("begin tower-based peer handling test stub");
+
+        let node = Buffer::new(
+            service_fn(|req| {
+                async move {
+                    info!(?req);
+                    Ok::<Response, failure::Error>(Response::Ok)
+                }
+            }),
+            1,
+        );
+
+        let config = app_config().network.clone();
+
+        // XXX How do I create a service above that answers questions
+        // about this specific address book?
+        let (mut peer_set, address_book) = zebra_network::init(config, node).await;
+
+        // XXX Do not tell our DNS seed queries about gossiped addrs
+        // that we have not connected to before?
+        info!("waiting for peer_set ready");
+        peer_set.ready().await.map_err(Error::from_boxed_compat)?;
+
+        info!("peer_set became ready");
+
+        loop {}
+
+        Ok(())
+    }
+}