fedimint_client/
api_announcements.rs

1use std::collections::BTreeMap;
2use std::sync::Arc;
3use std::time::Duration;
4
5use anyhow::{Context, bail};
6use fedimint_core::config::ClientConfig;
7use fedimint_core::db::{Database, IDatabaseTransactionOpsCoreTyped};
8use fedimint_core::encoding::{Decodable, Encodable};
9use fedimint_core::net::api_announcement::{SignedApiAnnouncement, override_api_urls};
10use fedimint_core::runtime::sleep;
11use fedimint_core::secp256k1::SECP256K1;
12use fedimint_core::util::{SafeUrl, backoff_util, retry};
13use fedimint_core::{PeerId, impl_db_lookup, impl_db_record};
14use fedimint_logging::LOG_CLIENT;
15use futures::future::join_all;
16use tracing::{debug, warn};
17
18use crate::Client;
19use crate::db::DbKeyPrefix;
20
21#[derive(Clone, Debug, Encodable, Decodable)]
22pub struct ApiAnnouncementKey(pub PeerId);
23
24#[derive(Clone, Debug, Encodable, Decodable)]
25pub struct ApiAnnouncementPrefix;
26
27impl_db_record!(
28    key = ApiAnnouncementKey,
29    value = SignedApiAnnouncement,
30    db_prefix = DbKeyPrefix::ApiUrlAnnouncement,
31    notify_on_modify = false,
32);
33impl_db_lookup!(
34    key = ApiAnnouncementKey,
35    query_prefix = ApiAnnouncementPrefix
36);
37
38/// Fetches API URL announcements from guardians, validates them and updates the
39/// DB if any new more upt to date ones are found.
40pub async fn run_api_announcement_sync(client_inner: Arc<Client>) {
41    // Wait for the guardian keys to be available
42    let guardian_pub_keys = client_inner.get_guardian_public_keys_blocking().await;
43    loop {
44        let results = join_all(client_inner.api.all_peers().iter()
45            .map(|peer_id| async {
46                let peer_id = *peer_id;
47                let announcements =
48
49                retry(
50                    "Fetch api announcement (sync)",
51                    backoff_util::aggressive_backoff(),
52                    || async {
53                        client_inner
54                            .api
55                            .api_announcements(peer_id)
56                            .await
57                            .with_context(move || format!("Fetching API announcements from peer {peer_id} failed"))
58                    },
59                )
60                .await?;
61
62                // If any of the announcements is invalid something is fishy with that
63                // guardian and we ignore all its responses
64                for (peer_id, announcement) in &announcements {
65                    let Some(guardian_pub_key) = guardian_pub_keys.get(peer_id) else {
66                        bail!("Guardian public key not found for peer {}", peer_id);
67                    };
68
69                    if !announcement.verify(SECP256K1, guardian_pub_key) {
70                        bail!("Failed to verify announcement for peer {}", peer_id);
71                    }
72                }
73
74                client_inner
75                    .db()
76                    .autocommit(
77                        |dbtx, _|{
78                            let announcements_inner = announcements.clone();
79                        Box::pin(async move {
80                            for (peer, new_announcement) in announcements_inner {
81                                let replace_current_announcement = dbtx
82                                    .get_value(&ApiAnnouncementKey(peer))
83                                    .await.is_none_or(|current_announcement| {
84                                        current_announcement.api_announcement.nonce
85                                            < new_announcement.api_announcement.nonce
86                                    });
87                                if replace_current_announcement {
88                                    debug!(target: LOG_CLIENT, ?peer, %new_announcement.api_announcement.api_url, "Updating API announcement");
89                                    dbtx.insert_entry(&ApiAnnouncementKey(peer), &new_announcement)
90                                        .await;
91                                }
92                            }
93
94                            Result::<(), ()>::Ok(())
95                        })},
96                        None,
97                    )
98                    .await
99                    .expect("Will never return an error");
100
101                Ok(())
102            })).await;
103
104        for (peer_id, result) in guardian_pub_keys.keys().zip(results) {
105            if let Err(e) = result {
106                warn!(target: LOG_CLIENT, %peer_id, ?e, "Failed to process API announcements");
107            }
108        }
109
110        // Check once an hour if there are new announcements
111        sleep(Duration::from_secs(3600)).await;
112    }
113}
114
115/// Returns a list of all peers and their respective API URLs taking into
116/// account announcements overwriting the URLs contained in the original
117/// configuration.
118pub async fn get_api_urls(db: &Database, cfg: &ClientConfig) -> BTreeMap<PeerId, SafeUrl> {
119    override_api_urls(
120        db,
121        cfg.global
122            .api_endpoints
123            .iter()
124            .map(|(peer_id, peer_url)| (*peer_id, peer_url.url.clone())),
125        &ApiAnnouncementPrefix,
126        |key| key.0,
127    )
128    .await
129}
fedimint_client/api_announcements.rs

fedimint_client/
api_announcements.rs
