feat: implement signer metrics exporter (#1084)

* Add an initial metrics setup module
* Set up metrics from the settings
* Add a few counter and histogram metrics

Cargo.toml

@@ -44,6 +44,8 @@ config = "0.11.0"
 futures = "0.3.24"
 hashbrown = "0.14.5"
 http = "1.1.0"
+metrics = "0.24"
+metrics-exporter-prometheus = { version = "0.16", default-features = false, features = ["http-listener"] }
 # This is necessary to compile the AWS Lambda as a lambda.
 openssl = { version = "0.10.66", features = ["vendored"] }
 p256k1 = "7.1.0"

signer/Cargo.toml

@@ -27,6 +27,8 @@ config = "0.14"
 futures.workspace = true
 hashbrown.workspace = true
 libp2p.workspace = true
+metrics.workspace = true
+metrics-exporter-prometheus.workspace = true
 p256k1.workspace = true
 prost.workspace = true
 rand.workspace = true

signer/build.rs

@@ -1,7 +1,33 @@
 fn main() {
+    set_up_build_info();
     // compile_protos();
 }
 
+pub fn set_up_build_info() {
+    let output = std::process::Command::new("rustc")
+        .arg("--version")
+        .output()
+        .expect("Failed to execute rustc");
+
+    let version = String::from_utf8_lossy(&output.stdout);
+
+    let git_hash = std::process::Command::new("git")
+        .args(["rev-parse", "HEAD"])
+        .output()
+        .map(|output| String::from_utf8_lossy(&output.stdout).to_string())
+        .unwrap_or_default();
+
+    let env_abi = std::env::var("CARGO_CFG_TARGET_ENV").unwrap();
+    let arch = std::env::var("CARGO_CFG_TARGET_ARCH").unwrap();
+
+    // We capture these variables in our binary and use them in the
+    // build_info metric.
+    println!("cargo:rustc-env=CARGO_CFG_TARGET_ENV={}", env_abi.trim());
+    println!("cargo:rustc-env=CARGO_CFG_TARGET_ARCH={}", arch.trim());
+    println!("cargo:rustc-env=GIT_COMMIT={}", git_hash.trim());
+    println!("cargo:rustc-env=RUSTC_VERSION={}", version.trim());
+}
+
 pub fn compile_protos() {
     let workingdir = std::path::Path::new(env!("CARGO_MANIFEST_DIR"))
         .parent()

signer/src/api/new_block.rs

@@ -22,6 +22,8 @@ use std::sync::OnceLock;
 use crate::context::Context;
 use crate::emily_client::EmilyInteract;
 use crate::error::Error;
+use crate::metrics::Metrics;
+use crate::metrics::STACKS_BLOCKCHAIN;
 use crate::stacks::events::CompletedDepositEvent;
 use crate::stacks::events::KeyRotationEvent;
 use crate::stacks::events::RegistryEvent;
@@ -79,6 +81,12 @@ enum UpdateResult {
 #[tracing::instrument(skip_all, name = "new-block")]
 pub async fn new_block_handler(state: State<ApiState<impl Context>>, body: String) -> StatusCode {
     tracing::debug!("received a new block event from stacks-core");
+    metrics::counter!(
+        Metrics::BlocksObservedTotal,
+        "blockchain" => STACKS_BLOCKCHAIN,
+    )
+    .increment(1);
+
     let api = state.0;
 
     let registry_address = SBTC_REGISTRY_IDENTIFIER.get_or_init(|| {

signer/src/block_observer.rs

@@ -28,6 +28,8 @@ use crate::context::SbtcLimits;
 use crate::context::SignerEvent;
 use crate::emily_client::EmilyInteract;
 use crate::error::Error;
+use crate::metrics::Metrics;
+use crate::metrics::BITCOIN_BLOCKCHAIN;
 use crate::stacks::api::StacksInteract;
 use crate::stacks::api::TenureBlocks;
 use crate::storage;
@@ -137,6 +139,11 @@ where
             match poll.await {
                 Ok(Some(Ok(block_hash))) => {
                     tracing::info!("observed new bitcoin block from stream");
+                    metrics::counter!(
+                        Metrics::BlocksObservedTotal,
+                        "blockchain" => BITCOIN_BLOCKCHAIN,
+                    )
+                    .increment(1);
 
                     let next_blocks = match self.next_blocks_to_process(block_hash).await {
                         Ok(blocks) => blocks,
@@ -203,17 +210,31 @@ impl<C: Context, B> BlockObserver<C, B> {
     #[tracing::instrument(skip_all)]
     pub async fn load_requests(&self, requests: &[CreateDepositRequest]) -> Result<(), Error> {
         let mut deposit_requests = Vec::new();
+        let bitcoin_client = self.context.get_bitcoin_client();
+
         for request in requests {
             let deposit = request
-                .validate(&self.context.get_bitcoin_client())
+                .validate(&bitcoin_client)
                 .await
                 .inspect_err(|error| tracing::warn!(%error, "could not validate deposit request"));
 
             // We log the error above, so we just need to extract the
             // deposit now.
-            if let Ok(Some(deposit)) = deposit {
-                deposit_requests.push(deposit);
-            }
+            let deposit_status = match deposit {
+                Ok(Some(deposit)) => {
+                    deposit_requests.push(deposit);
+                    "success"
+                }
+                Ok(None) => "unconfirmed",
+                Err(_) => "failed",
+            };
+
+            metrics::counter!(
+                Metrics::DepositRequestsTotal,
+                "blockchain" => BITCOIN_BLOCKCHAIN,
+                "status" => deposit_status,
+            )
+            .increment(1);
         }
 
         self.store_deposit_requests(deposit_requests).await?;
@@ -435,6 +456,13 @@ impl<C: Context, B> BlockObserver<C, B> {
 
             for prevout in tx_info.to_inputs(&signer_script_pubkeys) {
                 db.write_tx_prevout(&prevout).await?;
+                if prevout.prevout_type == model::TxPrevoutType::Deposit {
+                    metrics::counter!(
+                        Metrics::DepositsSweptTotal,
+                        "blockchain" => BITCOIN_BLOCKCHAIN,
+                    )
+                    .increment(1);
+                }
             }
 
             for output in tx_info.to_outputs(&signer_script_pubkeys) {

signer/src/config/default.toml

@@ -184,6 +184,13 @@ dkg_max_duration = 120
 # Environment: SIGNER_SIGNER__DKG_BEGIN_PAUSE
 # dkg_begin_pause = 10
 
+# When defined, this field sets the scrape endpoint as an IPv4 or IPv6
+# socket address for exporting metrics for Prometheus.
+#
+# Required: false
+# Environment: SIGNER_SIGNER__PROMETHEUS_EXPORTER_ENDPOINT
+# prometheus_exporter_endpoint = "[::]:9184"
+
 # !! ==============================================================================
 # !! Stacks Event Observer Configuration
 # !!
@@ -272,4 +279,4 @@ public_endpoints = []
 # Default: false
 # Required: false
 # Environment: SIGNER_SIGNER__P2P__ENABLE_MDNS
-enable_mdns = true
+enable_mdns = true