Add SnapshotDownloadMessage type

Author: jpraynaud

mithril-common/src/messages/mod.rs

@@ -11,6 +11,7 @@ mod mithril_stake_distribution_list;
 mod register_signature;
 mod register_signer;
 mod snapshot;
+mod snapshot_download;
 mod snapshot_list;
 
 pub use certificate::CertificateMessage;
@@ -28,4 +29,5 @@ pub use mithril_stake_distribution_list::{
 pub use register_signature::RegisterSignatureMessage;
 pub use register_signer::RegisterSignerMessage;
 pub use snapshot::SnapshotMessage;
+pub use snapshot_download::SnapshotDownloadMessage;
 pub use snapshot_list::{SnapshotListItemMessage, SnapshotListMessage};

mithril-common/src/messages/snapshot_download.rs

@@ -0,0 +1,88 @@
+use serde::{Deserialize, Serialize};
+
+use crate::entities::{Beacon, CompressionAlgorithm, Epoch};
+
+/// Message structure of a snapshot
+#[derive(Clone, Debug, PartialEq, Eq, Default, Serialize, Deserialize)]
+pub struct SnapshotDownloadMessage {
+    /// Digest that is signed by the signer participants
+    pub digest: String,
+
+    /// Mithril beacon on the Cardano chain
+    pub beacon: Beacon,
+
+    /// Size of the snapshot file in Bytes
+    pub size: u64,
+
+    /// Locations where the binary content of the snapshot can be retrieved
+    pub locations: Vec<String>,
+
+    /// Compression algorithm of the snapshot archive
+    pub compression_algorithm: CompressionAlgorithm,
+
+    /// Cardano node version
+    pub cardano_node_version: String,
+}
+
+impl SnapshotDownloadMessage {
+    /// Return a dummy test entity (test-only).
+    pub fn dummy() -> Self {
+        Self {
+            digest: "0b9f5ad7f33cc523775c82249294eb8a1541d54f08eb3107cafc5638403ec7c6".to_string(),
+            beacon: Beacon {
+                network: "preview".to_string(),
+                epoch: Epoch(86),
+                immutable_file_number: 1728,
+            },
+            size: 807803196,
+            locations: vec!["https://host/certificate.tar.gz".to_string()],
+            compression_algorithm: CompressionAlgorithm::Gzip,
+            cardano_node_version: "0.0.1".to_string(),
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    fn golden_message_v1() -> SnapshotDownloadMessage {
+        SnapshotDownloadMessage {
+            digest: "0b9f5ad7f33cc523775c82249294eb8a1541d54f08eb3107cafc5638403ec7c6".to_string(),
+            beacon: Beacon {
+                network: "preview".to_string(),
+                epoch: Epoch(86),
+                immutable_file_number: 1728,
+            },
+            size: 807803196,
+            locations: vec!["https://host/certificate.tar.gz".to_string()],
+            compression_algorithm: CompressionAlgorithm::Gzip,
+            cardano_node_version: "0.0.1".to_string(),
+        }
+    }
+
+    // Test the retro compatibility with possible future upgrades.
+    #[test]
+    fn test_v1() {
+        let json = r#"{
+"digest": "0b9f5ad7f33cc523775c82249294eb8a1541d54f08eb3107cafc5638403ec7c6",
+"beacon": {
+  "network": "preview",
+  "epoch": 86,
+  "immutable_file_number": 1728
+},
+"size": 807803196,
+"locations": [
+  "https://host/certificate.tar.gz"
+],
+"compression_algorithm": "gzip",
+"cardano_node_version": "0.0.1"
+}
+"#;
+        let message: SnapshotDownloadMessage = serde_json::from_str(json).expect(
+            "This JSON is expected to be succesfully parsed into a SnapshotDownloadMessage instance.",
+        );
+
+        assert_eq!(golden_message_v1(), message);
+    }
+}