feat: simple aggregator discovery #2779

jpraynaud · 2025-11-14T16:10:29Z

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- Tests are provided (if possible)
- Crates versions are updated (if relevant)
- CHANGELOG file is updated (if relevant)
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- All check jobs of the CI have succeeded
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- No new TODOs introduced

Issue(s)

Closes #2726

internal/mithril-aggregator-discovery/src/capabilities_discoverer.rs

+    type Item = AggregatorEndpoint;
+
+    fn next(&mut self) -> Option<Self::Item> {
+        while let Some(aggregator_endpoint) = self.inner_iterator.next() {


internal/mithril-aggregator-discovery/src/capabilities_discoverer.rs

+    type Item = AggregatorEndpoint;
+
+    fn next(&mut self) -> Option<Self::Item> {
+        while let Some(aggregator_endpoint) = self.inner_iterator.next() {


internal/mithril-aggregator-discovery/src/capabilities_discoverer.rs

+            if let Ok(aggregator_capabilities) = aggregator_capabilities {
+                if CapableAggregatorDiscoverer::capabilities_match(
+                    &self.capabilities,
+                    &aggregator_capabilities,
+                ) {
+                    return Some(aggregator_endpoint);
+                }
+            }


internal/mithril-aggregator-discovery/src/capabilities_discoverer.rs

+            if let Ok(aggregator_capabilities) = aggregator_capabilities {
+                if CapableAggregatorDiscoverer::capabilities_match(
+                    &self.capabilities,
+                    &aggregator_capabilities,
+                ) {
+                    return Some(aggregator_endpoint);
+                }
+            }


mithril-client/src/client.rs

+                return Err(anyhow!(
+                    "The genesis verification key must be provided to build the client with the 'with_genesis_verification_key' function"
+                )
+                .into());


mithril-client/src/client.rs

+                return Err(anyhow!(
+                    "The genesis verification key must be provided to build the client with the 'with_genesis_verification_key' function"
+                )
+                .into());


Copilot

Pull Request Overview

This PR implements a simple aggregator discovery mechanism to enable the Mithril client to automatically discover and connect to available aggregators in a network.

Key changes:

Introduces a new mithril-aggregator-discovery crate with discoverer implementations
Refactors the ClientBuilder API to support aggregator discovery modes (automatic vs. explicit URL)
Adds capability-based filtering and randomization of aggregator selection

Reviewed Changes

Copilot reviewed 18 out of 20 changed files in this pull request and generated 5 comments.

Show a summary per file

File	Description
`internal/mithril-aggregator-discovery/Cargo.toml`	Defines the new aggregator discovery crate with dependencies
`internal/mithril-aggregator-discovery/src/lib.rs`	Exports the public API for aggregator discovery
`internal/mithril-aggregator-discovery/src/interface.rs`	Defines the `AggregatorDiscoverer` trait
`internal/mithril-aggregator-discovery/src/model.rs`	Implements `MithrilNetwork` and `AggregatorEndpoint` models
`internal/mithril-aggregator-discovery/src/http_config_discoverer.rs`	HTTP-based discoverer that fetches aggregator lists from remote configuration
`internal/mithril-aggregator-discovery/src/capabilities_discoverer.rs`	Filters aggregators by required capabilities
`internal/mithril-aggregator-discovery/src/rand_discoverer.rs`	Shuffles aggregator order using randomization
`internal/mithril-aggregator-discovery/src/test/`	Test utilities and doubles for testing
`mithril-client/src/client.rs`	Refactors client builder to support aggregator discovery
`mithril-client/Cargo.toml`	Adds dependency on the new discovery crate
`Makefile`, `Cargo.toml`, `.github/workflows/ci.yml`	Build configuration updates
`README.md`	Documentation for the new crate

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Copilot · 2025-11-14T16:13:23Z

internal/mithril-aggregator-discovery/src/test/double/discoverer.rs

+impl AggregatorDiscovererFake {
+    /// Creates a new `AggregatorDiscovererFake` instance with the provided results.
+    pub fn new(results: Vec<AggregatorListReturn>) -> Self {
+        dbg!(&results);


Debug statement should be removed. This dbg! macro call will print to stderr in production code and is typically used only during development.

Suggested change

dbg!(&results);

Copilot · 2025-11-14T16:13:23Z

internal/mithril-aggregator-discovery/src/interface.rs

+pub trait AggregatorDiscoverer: Sync + Send {
+    /// Get an iterator over a list of available aggregators in a Mithril network.
+    ///
+    /// Note: there is no guarantee that the returned aggregators is sorted, complete or up-to-date.


Corrected grammar: 'aggregators is' should be 'aggregators are'.

Suggested change

/// Note: there is no guarantee that the returned aggregators is sorted, complete or up-to-date.

/// Note: there is no guarantee that the returned aggregators are sorted, complete or up-to-date.

Copilot · 2025-11-14T16:13:24Z

internal/mithril-aggregator-discovery/Cargo.toml

@@ -0,0 +1,44 @@
+[package]
+name = "mithril-aggregator-discovery"
+description = "Mechanisms to discover aggregator available in a Mithril network."


Corrected grammar: 'aggregator available' should be 'aggregators available'.

Suggested change

description = "Mechanisms to discover aggregator available in a Mithril network."

description = "Mechanisms to discover aggregators available in a Mithril network."

Copilot · 2025-11-14T16:13:24Z

mithril-client/src/client.rs

+        let aggregator_endpoint = match self.aggregator_discovery {
+            AggregatorDiscoveryType::Url(ref url) => url.clone(),
+            AggregatorDiscoveryType::Automatic => {
+                todo!("Implement automatic aggregator discovery")


The todo!() macro will panic at runtime if this code path is executed. Since AggregatorDiscoveryType::Automatic is a public API variant, this creates a potential runtime failure. Consider either removing the Automatic variant until implemented, or returning a proper error with context.

Suggested change

todo!("Implement automatic aggregator discovery")

return Err(anyhow!("Automatic aggregator discovery is not yet implemented"));

Copilot · 2025-11-14T16:13:24Z

README.md

+
+  - [**Mithril aggregator client**](./internal/mithril-aggregator-client): a client to request data from a Mithril aggregator, used by **Mithril network** nodes and client library.
+
+  - [**Mithril aggregator discovery**](./internal/mithril-aggregator-discovery): mechanisms to discover available Mithril aggregator, used by **Mithril network** nodes and client library.


Corrected grammar: 'aggregator' should be 'aggregators'.

Suggested change

- [**Mithril aggregator discovery**](./internal/mithril-aggregator-discovery): mechanisms to discover available Mithril aggregator, used by **Mithril network** nodes and client library.

- [**Mithril aggregator discovery**](./internal/mithril-aggregator-discovery): mechanisms to discover available Mithril aggregators, used by **Mithril network** nodes and client library.

github-actions · 2025-11-14T16:18:31Z

Test Results

4 files ± 0 172 suites +4 23m 21s ⏱️ -28s
2 221 tests +11 2 221 ✅ +11 0 💤 ±0 0 ❌ ±0
6 939 runs +44 6 939 ✅ +44 0 💤 ±0 0 ❌ ±0

Results for commit c74fb50. ± Comparison against base commit 2c3dd53.

♻️ This comment has been updated with latest results.

…rer' trait

Implementation for 'AggregatorDiscoverer' trait.

…rator

…ementation of 'Iterator' trait

…rIterator'

…builder

mithril-client/src/client.rs

+                            .into()
+                    }
+                    None => {
+                        return Err(anyhow!("The aggregator discoverer must be provided to build the client with automatic discovery using the 'with_aggregator_discoverer' function").into());


mithril-client/src/client.rs

+                            .into()
+                    }
+                    None => {
+                        return Err(anyhow!("The aggregator discoverer must be provided to build the client with automatic discovery using the 'with_aggregator_discoverer' function").into());


jpraynaud self-assigned this Nov 14, 2025

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jpraynaud requested a review from Copilot November 14, 2025 16:11

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Copilot AI reviewed Nov 14, 2025

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jpraynaud added 16 commits November 17, 2025 14:56

chore(aggregator-discovery): scaffold new crate

2fa8023

feat(aggregator-discovery): add models for aggregator endpoint

71bfe5e

feat(aggregator-discovery): introduce 'AggregatorDiscoverer' trait

2e4c8e0

feat(aggregator-discovery): create test double for 'AggregatorDiscove…

2e82173

…rer' trait

feat(aggregator-discovery): add 'HttpConfigAggregatorDiscoverer'

f010b78

Implementation for 'AggregatorDiscoverer' trait.

refactor(aggregator-discovery): 'AggregatorDiscoverer' returns an ite…

c359be4

…rator

feat(aggregator-discovery): add 'ShuffleAggregatorDiscoverer' decorator

a53082c

wip(aggregator-discovery): add 'CapableAggregatorDiscoverer' decorator

1a973a2

fix(aggregator-discovery): 'CapableAggregatorDiscovererIterator' impl…

5c86f94

…ementation of 'Iterator' trait

test(aggregator-discovery): add tests for 'CapableAggregatorDiscovere…

670d9eb

…rIterator'

refactor(client): prepare client builder for aggregator discovery

501ab94

fix(aggregator-discovery): remove unneeded 'crate-type' in 'Cargo.toml'

def6df0

feat(client): implement basic aggregator discoverer

b1f1cd4

feat(client-cli): update client builder to async

85423cc

feat(examples): update client builder to async

f620d4d

feat(aggregator-discovery): implement aggregator discovery in client …

c74fb50

…builder

jpraynaud force-pushed the jpraynaud/2726-simple-aggregator-discovery branch from 945d3c2 to c74fb50 Compare November 17, 2025 16:29

github-advanced-security bot found potential problems Nov 17, 2025

View reviewed changes

	/// Note: there is no guarantee that the returned aggregators is sorted, complete or up-to-date.
	/// Note: there is no guarantee that the returned aggregators are sorted, complete or up-to-date.

	description = "Mechanisms to discover aggregator available in a Mithril network."
	description = "Mechanisms to discover aggregators available in a Mithril network."

	todo!("Implement automatic aggregator discovery")
	return Err(anyhow!("Automatic aggregator discovery is not yet implemented"));


		- [Mithril aggregator client](./internal/mithril-aggregator-client): a client to request data from a Mithril aggregator, used by Mithril network nodes and client library.

		- [Mithril aggregator discovery](./internal/mithril-aggregator-discovery): mechanisms to discover available Mithril aggregator, used by Mithril network nodes and client library.

feat: simple aggregator discovery #2779

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