Remove telemetry and rest-server feature flags

.changelog/unreleased/breaking-changes/ibc-telemetry/3878-remove-telemetry-flag.md

@@ -0,0 +1,3 @@
+- Remove the `telemetry` and `rest-server` feature flags, ensuring Hermes is always built with telemetry and REST support.
+  Both servers can still be disabled in the configuration file, by setting `telemtry.enabled = false` and `rest.enabled = false`, respectively.
+  ([\#3878](https://github.com/informalsystems/hermes/pull/3878))

crates/relayer-cli/Cargo.toml

@@ -17,18 +17,11 @@ default-run = "hermes"
 [[bin]]
 name = "hermes"
 
-[features]
-default     = ["telemetry", "rest-server", "std", "eyre_tracer"]
-std         = ["flex-error/std"]
-eyre_tracer = ["flex-error/eyre_tracer"]
-telemetry   = ["ibc-relayer/telemetry", "ibc-telemetry"]
-rest-server = ["ibc-relayer-rest"]
-
 [dependencies]
 ibc-relayer-types  = { workspace = true }
 ibc-relayer        = { workspace = true }
-ibc-telemetry      = { workspace = true, optional = true }
-ibc-relayer-rest   = { workspace = true, optional = true }
+ibc-telemetry      = { workspace = true }
+ibc-relayer-rest   = { workspace = true }
 ibc-chain-registry = { workspace = true }
 
 abscissa_core                    = { workspace = true, features = ["options"] }

crates/relayer-cli/src/commands/start.rs

@@ -131,7 +131,6 @@ fn register_signals(tx_cmd: Sender<SupervisorCmd>) -> Result<(), io::Error> {
     Ok(())
 }
 
-#[cfg(feature = "rest-server")]
 fn spawn_rest_server(config: &Config) -> Option<rest::Receiver> {
     use ibc_relayer::util::spawn_blocking;
 
@@ -169,23 +168,6 @@ fn spawn_rest_server(config: &Config) -> Option<rest::Receiver> {
     Some(rx)
 }
 
-#[cfg(not(feature = "rest-server"))]
-fn spawn_rest_server(config: &Config) -> Option<rest::Receiver> {
-    let rest = config.rest.clone();
-
-    if rest.enabled {
-        warn!(
-            "REST server enabled in the config but Hermes was built without REST support, \
-             build Hermes with --features=rest-server to enable REST support."
-        );
-
-        None
-    } else {
-        None
-    }
-}
-
-#[cfg(feature = "telemetry")]
 fn spawn_telemetry_server(config: &Config) {
     use ibc_relayer::util::spawn_blocking;
 
@@ -220,16 +202,6 @@ fn spawn_telemetry_server(config: &Config) {
     });
 }
 
-#[cfg(not(feature = "telemetry"))]
-fn spawn_telemetry_server(config: &Config) {
-    if config.telemetry.enabled {
-        warn!(
-            "telemetry enabled in the config but Hermes was built without telemetry support, \
-             build Hermes with --features=telemetry to enable telemetry support."
-        );
-    }
-}
-
 fn make_supervisor<Chain: ChainHandle>(
     config: Config,
     options: SupervisorOptions,

crates/relayer/Cargo.toml

@@ -17,11 +17,10 @@ all-features = true
 
 [features]
 default   = ["flex-error/std", "flex-error/eyre_tracer"]
-telemetry = ["ibc-telemetry"]
 
 [dependencies]
 ibc-proto         = { workspace = true, features = ["serde"] }
-ibc-telemetry     = { workspace = true, optional = true }
+ibc-telemetry     = { workspace = true }
 ibc-relayer-types = { workspace = true, features = ["clock"] }
 
 anyhow                           = { workspace = true }

crates/relayer/src/chain/cosmos/estimate.rs

@@ -212,7 +212,6 @@ fn can_recover_from_simulation_failure(e: &Error) -> bool {
     }
 }
 
-#[cfg(feature = "telemetry")]
 fn get_error_text(e: &Error) -> String {
     use crate::error::ErrorDetail::*;
 

crates/relayer/src/link/relay_path.rs

@@ -1845,7 +1845,6 @@ impl<ChainA: ChainHandle, ChainB: ChainHandle> RelayPath<ChainA, ChainB> {
     }
 
     // we need fully qualified ChainId to avoid unneeded imports warnings
-    #[cfg(feature = "telemetry")]
     fn target_info(
         &self,
         target: OperationalDataTarget,
@@ -1871,7 +1870,6 @@ impl<ChainA: ChainHandle, ChainB: ChainHandle> RelayPath<ChainA, ChainB> {
         }
     }
 
-    #[cfg(feature = "telemetry")]
     fn backlog_update(&self, event: &IbcEvent) {
         match event {
             IbcEvent::SendPacket(send_packet_ev) => {
@@ -1905,7 +1903,6 @@ impl<ChainA: ChainHandle, ChainB: ChainHandle> RelayPath<ChainA, ChainB> {
         }
     }
 
-    #[cfg(feature = "telemetry")]
     fn record_cleared_send_packet(&self, event_with_height: &IbcEventWithHeight) {
         if let IbcEvent::SendPacket(send_packet_ev) = &event_with_height.event {
             ibc_telemetry::global().send_packet_events(
@@ -1927,7 +1924,6 @@ impl<ChainA: ChainHandle, ChainB: ChainHandle> RelayPath<ChainA, ChainB> {
         }
     }
 
-    #[cfg(feature = "telemetry")]
     fn record_cleared_acknowledgments<'a>(
         &self,
         events_with_heights: impl Iterator<Item = &'a IbcEventWithHeight>,

crates/relayer/src/supervisor.rs

@@ -848,7 +848,6 @@ fn process_batch<Chain: ChainHandle>(
 /// So successfully sending a packet from chain A to chain B will result in first a SendPacket
 /// event with `chain_id = A` and `counterparty_chain_id = B` and then a WriteAcknowlegment
 /// event with `chain_id = B` and `counterparty_chain_id = A`.
-#[cfg(feature = "telemetry")]
 fn send_telemetry<Src, Dst>(
     src: &Src,
     dst: &Dst,

crates/relayer/src/telemetry.rs

@@ -1,15 +1,6 @@
 // If the `telemetry` feature is enabled, re-export the `ibc-telemetry` state.
-#[cfg(feature = "telemetry")]
 pub type Telemetry = alloc::sync::Arc<ibc_telemetry::TelemetryState>;
 
-// Otherwise, define and export a dummy type.
-#[cfg(not(feature = "telemetry"))]
-#[derive(Clone, Debug)]
-pub struct TelemetryDisabled;
-
-#[cfg(not(feature = "telemetry"))]
-pub type Telemetry = TelemetryDisabled;
-
 /// A macro to send metric updates via a telemetry handle,
 /// only if the `telemetry` feature is enabled.
 /// Otherwise, it compiles to a no-op.
@@ -32,7 +23,6 @@ pub type Telemetry = TelemetryDisabled;
 #[macro_export]
 macro_rules! telemetry {
     ($id:ident, $($args:expr),* $(,)*) => {
-        #[cfg(feature = "telemetry")]
         #[allow(unused_imports, unused_variables)]
         {
             use ::ibc_telemetry::state::WorkerType;
@@ -42,7 +32,6 @@ macro_rules! telemetry {
     };
 
     ($e:expr) => {
-        #[cfg(feature = "telemetry")]
         #[allow(unused_imports, unused_variables)]
         {
             use ::ibc_telemetry::state::WorkerType;

crates/relayer/src/worker/map.rs

@@ -252,7 +252,6 @@ impl Drop for WorkerMap {
     }
 }
 
-#[cfg(feature = "telemetry")]
 fn metric_type(o: &Object) -> ibc_telemetry::state::WorkerType {
     use ibc_telemetry::state::WorkerType;
 

crates/relayer/src/worker/packet.rs

@@ -484,10 +484,8 @@ fn lowest_sequence(events: &[IbcEventWithHeight]) -> Option<Sequence> {
         .min()
 }
 
-#[cfg(feature = "telemetry")]
 use crate::link::RelaySummary;
 
-#[cfg(feature = "telemetry")]
 fn packet_metrics(
     path: &Packet,
     summary: &RelaySummary,
@@ -499,7 +497,6 @@ fn packet_metrics(
     timeout_metrics(path, summary, dst_channel, dst_port);
 }
 
-#[cfg(feature = "telemetry")]
 fn receive_packet_metrics(
     path: &Packet,
     summary: &RelaySummary,
@@ -526,7 +523,6 @@ fn receive_packet_metrics(
     );
 }
 
-#[cfg(feature = "telemetry")]
 fn acknowledgment_metrics(
     path: &Packet,
     summary: &RelaySummary,
@@ -553,7 +549,6 @@ fn acknowledgment_metrics(
     );
 }
 
-#[cfg(feature = "telemetry")]
 fn timeout_metrics(
     path: &Packet,
     summary: &RelaySummary,