feature: Add a checkpoint_sync config option

(The option doesn't do anything yet.)

Cargo.lock

@@ -3085,6 +3085,7 @@ dependencies = [
  "once_cell",
  "rand 0.7.3",
  "redjubjub",
+ "serde",
  "spandoc",
  "tokio",
  "tower",

zebra-consensus/Cargo.toml

@@ -8,18 +8,19 @@ edition = "2018"
 [dependencies]
 chrono = "0.4.13"
 color-eyre = "0.5"
+once_cell = "1.4"
 rand = "0.7"
 redjubjub = "0.2"
+serde = { version = "1", features = ["serde_derive"] }
 
-metrics = "0.12"
 futures = "0.3.5"
 futures-util = "0.3.5"
+metrics = "0.12"
 tokio = { version = "0.2.22", features = ["time", "sync", "stream", "tracing"] }
 tower = "0.3"
 tower-util = "0.3"
 tracing = "0.1.19"
 tracing-futures = "0.2.4"
-once_cell = "1.4"
 
 tower-fallback = { path = "../tower-fallback/" }
 tower-batch = { path = "../tower-batch/" }

zebra-consensus/src/config.rs

@@ -0,0 +1,22 @@
+//! Configuration for zebra-consensus
+
+use serde::{Deserialize, Serialize};
+
+/// Consensus configuration.
+#[derive(Clone, Debug, Deserialize, Serialize)]
+#[serde(deny_unknown_fields, default)]
+pub struct Config {
+    /// Should Zebra sync using checkpoints?
+    ///
+    /// Setting this option to true enables post-Sapling checkpoints.
+    /// (Zebra always checkpoints on Sapling activation.)
+    pub checkpoint_sync: bool,
+}
+
+impl Default for Config {
+    fn default() -> Self {
+        Self {
+            checkpoint_sync: false,
+        }
+    }
+}

zebra-consensus/src/lib.rs

@@ -18,9 +18,13 @@
 pub mod block;
 pub mod chain;
 pub mod checkpoint;
+pub mod config;
 pub mod mempool;
 pub mod parameters;
+
 #[allow(dead_code)] // Remove this once transaction verification is implemented
 mod primitives;
 mod script;
 mod transaction;
+
+pub use crate::config::Config;

zebrad/src/config.rs

@@ -8,6 +8,7 @@ use std::{net::SocketAddr, path::PathBuf};
 
 use serde::{Deserialize, Serialize};
 
+use zebra_consensus::Config as ConsensusSection;
 use zebra_network::Config as NetworkSection;
 use zebra_state::Config as StateSection;
 
@@ -19,6 +20,9 @@ use zebra_state::Config as StateSection;
 #[derive(Clone, Default, Debug, Deserialize, Serialize)]
 #[serde(deny_unknown_fields, default)]
 pub struct ZebradConfig {
+    /// Consensus configuration
+    pub consensus: ConsensusSection,
+
     /// Metrics configuration
     pub metrics: MetricsSection,