Add new example showcasing apply_many
- Id
- 6aa9e9e2ce17cc70e503cc157cf7b0aaf212140b
- Author
- Caio
- Commit time
- 2026-07-03T09:47:23+02:00
Modified Cargo.toml
name = "foca_insecure_udp_agent"
required-features = ["std", "tracing", "bincode-codec"]
+[[example]]
+name = "bootstrap_with_wellknown"
+required-features = ["std", "bincode-codec"]
+
[dev-dependencies]
clap = { version = "2", default-features = false }
tokio = { version = "1", default-features = false, features = ["rt", "macros", "sync", "time", "net"] }
Created examples/bootstrap_with_wellknown.rs
+// This shows how one could teach foca about well known (or all)
+// members of a cluster
+//
+// The important steps are:
+//
+// - Teaching foca about these members via `Foca::apply_many`
+// - Ensuring the config option `periodic_announce_to_down_members`
+// is enabled (It's enabled by default for new_lan and new_lan constructors)
+//
+// This requires identities that have opted-in on automatic rejoining
+//
+// Notice that `apply_many` can also be used for a state sync protocal
+// (anti-entropy) and for restoring state after a restart
+use rand::{rngs::StdRng, SeedableRng};
+use std::{net::SocketAddr, num::NonZeroUsize, str::FromStr, time::Duration};
+
+use foca::{BincodeCodec, Config, Foca, Identity, Member, State};
+
+#[derive(Clone, PartialEq, Eq, Debug, serde::Serialize, serde::Deserialize)]
+struct ID {
+ addr: SocketAddr,
+ bump: u64,
+}
+
+fn main() {
+ let wellknown = [
+ SocketAddr::from_str("192.168.0.100:8080").unwrap(),
+ SocketAddr::from_str("192.168.0.101:8080").unwrap(),
+ SocketAddr::from_str("192.168.0.102:8080").unwrap(),
+ ];
+
+ let config = Config {
+ periodic_announce_to_down_members: Some(foca::PeriodicParams {
+ frequency: Duration::from_secs(60),
+ num_members: NonZeroUsize::new(3).unwrap(),
+ }),
+ // Never forget a member
+ remove_down_after: Duration::MAX,
+ ..Config::simple()
+ };
+
+ let ourselves = ID::new(SocketAddr::from_str("192.168.0.200:8080").unwrap(), 1);
+ let mut runtime = foca::AccumulatingRuntime::new();
+ let mut foca = Foca::new(
+ ourselves,
+ config,
+ StdRng::from_os_rng(),
+ BincodeCodec(bincode::config::standard()),
+ );
+
+ foca.apply_many(
+ wellknown
+ .iter()
+ .copied()
+ .map(ID::wellknown)
+ .map(|id| Member::new(id, 0, State::Down)),
+ false,
+ &mut runtime,
+ )
+ .unwrap();
+
+ // Go swimming!
+}
+
+impl ID {
+ fn wellknown(addr: SocketAddr) -> Self {
+ Self { addr, bump: 0 }
+ }
+
+ fn new(addr: SocketAddr, bump: u64) -> Self {
+ assert_ne!(0, bump);
+ Self { addr, bump }
+ }
+
+ fn bump(&self) -> Self {
+ let bump = if self.bump == u64::MAX {
+ 1
+ } else {
+ self.bump + 1
+ };
+
+ Self {
+ addr: self.addr,
+ bump,
+ }
+ }
+}
+
+impl Identity for ID {
+ type Addr = SocketAddr;
+
+ fn renew(&self) -> Option<Self> {
+ Some(self.bump())
+ }
+
+ fn addr(&self) -> Self::Addr {
+ self.addr
+ }
+
+ fn win_addr_conflict(&self, adversary: &Self) -> bool {
+ self.bump > adversary.bump
+ }
+}