feat: add support for Mithril era transition in clients

CHANGELOG.md

@@ -27,6 +27,8 @@ As a minor extension, we have adopted a slightly different versioning convention
 
 - Add pre-built Linux ARM binaries in the distribution for the signer, client CLI, and aggregator.
 
+- Support for Mithril era transition in the client library, CLI and WASM.
+
 - **UNSTABLE** :
   - Support for DMQ signature publisher in the signer and signature consumer in the aggregator.
 

docs/website/adr/004-mithril-network-update-strategy.md

@@ -92,3 +92,7 @@ sequenceDiagram
     Chain->>Old Node: Era change at Epoch XX
     Old Node->>User: 💀 unsupported Era, quit.
 ```
+
+### Client-side era awareness
+
+The Mithril clients do not have access to a Cardano node and therefore can not read the Era Activation Markers stored on chain. As a consequence, they rely on the current era run by the aggregator, by using the era advertised by its `/status` route.

internal/mithril-build-script/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "mithril-build-script"
-version = "0.2.24"
+version = "0.2.25"
 description = "A toolbox for Mithril crates build scripts"
 authors = { workspace = true }
 edition = { workspace = true }

internal/mithril-build-script/src/fake_aggregator.rs

@@ -14,6 +14,8 @@ pub type FileContent = String;
 /// of the fake aggregator.
 #[derive(Debug, Default)]
 pub struct FakeAggregatorData {
+    status: FileContent,
+
     epoch_settings: FileContent,
 
     certificates_list: FileContent,
@@ -50,6 +52,9 @@ impl FakeAggregatorData {
             });
 
             match filename.as_str() {
+                "status.json" => {
+                    data.status = file_content;
+                }
                 "epoch-settings.json" => {
                     data.epoch_settings = file_content;
                 }
@@ -155,6 +160,7 @@ impl FakeAggregatorData {
     pub fn generate_code_for_all_data(self) -> String {
         Self::assemble_code(
             &[
+                generate_list_getter("status", self.status),
                 generate_list_getter("epoch_settings", self.epoch_settings),
                 generate_ids_array(
                     "snapshot_digests",

mithril-client-cli/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "mithril-client-cli"
-version = "0.12.20"
+version = "0.12.21"
 description = "A Mithril Client"
 authors = { workspace = true }
 edition = { workspace = true }

mithril-client-cli/src/commands/mod.rs

@@ -12,21 +12,21 @@ pub mod tools;
 
 pub use deprecation::{DeprecatedCommand, Deprecation};
 
+use std::sync::Arc;
+
 use mithril_client::{ClientBuilder, MithrilResult};
 
-use crate::configuration::ConfigParameters;
+use crate::{configuration::ConfigParameters, utils::ForcedEraFetcher};
 
 const CLIENT_TYPE_CLI: &str = "CLI";
 
 pub(crate) fn client_builder(params: &ConfigParameters) -> MithrilResult<ClientBuilder> {
     let builder = ClientBuilder::aggregator(
         &params.require("aggregator_endpoint")?,
         &params.require("genesis_verification_key")?,
-    )
-    .with_origin_tag(params.get("origin_tag"))
-    .with_client_type(Some(CLIENT_TYPE_CLI.to_string()));
+    );
 
-    Ok(builder)
+    Ok(finalize_builder_config(builder, params))
 }
 
 pub(crate) fn client_builder_with_fallback_genesis_key(
@@ -44,9 +44,19 @@ pub(crate) fn client_builder_with_fallback_genesis_key(
             "genesis_verification_key",
             fallback_genesis_verification_key,
         ),
-    )
-    .with_origin_tag(params.get("origin_tag"))
-    .with_client_type(Some(CLIENT_TYPE_CLI.to_string()));
+    );
+
+    Ok(finalize_builder_config(builder, params))
+}
+
+fn finalize_builder_config(mut builder: ClientBuilder, params: &ConfigParameters) -> ClientBuilder {
+    builder = builder
+        .with_origin_tag(params.get("origin_tag"))
+        .with_client_type(Some(CLIENT_TYPE_CLI.to_string()));
+
+    if let Some(era) = params.get("era") {
+        builder = builder.with_era_fetcher(Arc::new(ForcedEraFetcher::new(era.to_string())));
+    }
 
-    Ok(builder)
+    builder
 }

mithril-client-cli/src/main.rs

@@ -91,6 +91,11 @@ pub struct Args {
     /// Request origin tag
     #[clap(long, global = true)]
     origin_tag: Option<String>,
+
+    /// Override the Mithril era
+    #[clap(long, global = true)]
+    #[example = "`pythagoras`"]
+    era: Option<String>,
 }
 
 impl Args {
@@ -208,6 +213,7 @@ impl Source for Args {
         let myself = self.clone();
         register_config_value_option!(map, &namespace, myself.aggregator_endpoint);
         register_config_value_option!(map, &namespace, myself.origin_tag);
+        register_config_value_option!(map, &namespace, myself.era);
 
         Ok(map)
     }

mithril-client-cli/src/utils/forced_era_fetcher.rs

@@ -0,0 +1,44 @@
+use async_trait::async_trait;
+
+use mithril_client::{
+    MithrilResult,
+    era::{EraFetcher, FetchedEra},
+};
+
+pub struct ForcedEraFetcher {
+    era: String,
+}
+
+impl ForcedEraFetcher {
+    pub fn new(era: String) -> Self {
+        Self { era }
+    }
+}
+
+#[async_trait]
+impl EraFetcher for ForcedEraFetcher {
+    async fn fetch_current_era(&self) -> MithrilResult<FetchedEra> {
+        Ok(FetchedEra {
+            era: self.era.clone(),
+        })
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[tokio::test]
+    async fn fetch_current_era_returns_fetched_era_with_forced_era_value() {
+        let era_fetcher = ForcedEraFetcher::new("forced_era".to_string());
+
+        let fetched_era = era_fetcher.fetch_current_era().await.unwrap();
+
+        assert_eq!(
+            FetchedEra {
+                era: "forced_era".to_string(),
+            },
+            fetched_era
+        );
+    }
+}

mithril-client-cli/src/utils/mod.rs

@@ -6,6 +6,7 @@ mod cardano_db;
 mod cardano_db_download_checker;
 mod expander;
 mod feedback_receiver;
+mod forced_era_fetcher;
 mod fs;
 mod github_release_retriever;
 mod http_downloader;
@@ -17,6 +18,7 @@ pub use cardano_db::*;
 pub use cardano_db_download_checker::*;
 pub use expander::*;
 pub use feedback_receiver::*;
+pub use forced_era_fetcher::*;
 pub use fs::*;
 pub use github_release_retriever::*;
 pub use http_downloader::*;

mithril-client-wasm/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "mithril-client-wasm"
-version = "0.9.3"
+version = "0.9.4"
 description = "Mithril client WASM"
 authors = { workspace = true }
 edition = { workspace = true }

mithril-client-wasm/package.json

@@ -1,6 +1,6 @@
 {
   "name": "@mithril-dev/mithril-client-wasm",
-  "version": "0.9.3",
+  "version": "0.9.4",
   "description": "Mithril client WASM",
   "license": "Apache-2.0",
   "collaborators": [

mithril-client-wasm/src/client_wasm.rs

@@ -424,6 +424,19 @@ impl MithrilClient {
 
         Ok(serde_wasm_bindgen::to_value(&result)?)
     }
+
+    /// Call the client to fetch the current Mithril era
+    #[wasm_bindgen]
+    pub async fn fetch_current_mithril_era(&self) -> WasmResult {
+        let result = self
+            .client
+            .mithril_era_client()
+            .fetch_current()
+            .await
+            .map_err(|err| format!("{err:?}"))?;
+
+        Ok(serde_wasm_bindgen::to_value(&result)?)
+    }
 }
 
 // Unstable functions are only available when the unstable flag is set
@@ -506,7 +519,7 @@ mod tests {
         CardanoDatabaseSnapshot, CardanoDatabaseSnapshotListItem, CardanoStakeDistribution,
         CardanoStakeDistributionListItem, CardanoTransactionSnapshot, MithrilCertificateListItem,
         MithrilStakeDistribution, MithrilStakeDistributionListItem, Snapshot, SnapshotListItem,
-        common::ProtocolMessage,
+        common::ProtocolMessage, common::SupportedEra, era::FetchedEra,
     };
 
     use crate::test_data;
@@ -960,4 +973,18 @@ mod tests {
             .await
             .expect_err("get_cardano_database_v2 should fail");
     }
+
+    #[wasm_bindgen_test]
+    async fn fetch_current_mithril_era_should_return_value_convertible_to_supported_era() {
+        let fetched_era_js_value = get_mithril_client_stable()
+            .fetch_current_mithril_era()
+            .await
+            .expect("fetch_current_mithril_era should not fail");
+        let fetched_era = serde_wasm_bindgen::from_value::<FetchedEra>(fetched_era_js_value)
+            .expect("conversion should not fail");
+
+        let era = fetched_era.to_supported_era().expect("conversion should not fail");
+
+        assert_eq!(era, SupportedEra::Pythagoras);
+    }
 }

mithril-client/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "mithril-client"
-version = "0.12.20"
+version = "0.12.21"
 description = "Mithril client library"
 authors = { workspace = true }
 edition = { workspace = true }

mithril-client/src/aggregator_client.rs

@@ -135,6 +135,9 @@ pub enum AggregatorRequest {
 
     /// Lists the aggregator [Cardano stake distribution][crate::CardanoStakeDistribution]
     ListCardanoStakeDistributions,
+
+    /// Get information about the aggregator status
+    Status,
 }
 
 impl AggregatorRequest {
@@ -197,6 +200,7 @@ impl AggregatorRequest {
             AggregatorRequest::ListCardanoStakeDistributions => {
                 "artifact/cardano-stake-distributions".to_string()
             }
+            AggregatorRequest::Status => "status".to_string(),
         }
     }
 
@@ -668,6 +672,8 @@ mod tests {
             "artifact/cardano-stake-distributions".to_string(),
             AggregatorRequest::ListCardanoStakeDistributions.route()
         );
+
+        assert_eq!("status".to_string(), AggregatorRequest::Status.route());
     }
 
     #[test]