Move to multi crates project

Starting impl devcontainer spec

crates/herald-server/src/metrics.rs

@@ -0,0 +1,62 @@
+use std::{net::SocketAddr, str::FromStr};
+
+use metrics::{Unit, describe_counter, describe_gauge, counter, gauge};
+
+pub fn webhook_received(event_type: &str) {
+    counter!("herald_webhooks_received_total", "event_type" => event_type.to_string())
+        .increment(1);
+}
+
+pub fn webhook_duplicate(event_type: &str) {
+    counter!("herald_webhooks_duplicate_total", "event_type" => event_type.to_string())
+        .increment(1);
+}
+
+pub fn webhook_channel_full(event_type: &str) {
+    counter!("herald_webhooks_channel_full_total", "event_type" => event_type.to_string())
+        .increment(1);
+}
+
+pub fn increment_task_active() {
+    gauge!("herald_bot_tasks_active").increment(1.0);
+}
+
+pub fn decrement_task_active() {
+    gauge!("herald_bot_tasks_active").decrement(1.0);
+}
+
+pub fn task_completed(event_type: &str) {
+    counter!("herald_bot_tasks_completed_total", "event_type" => event_type.to_string())
+        .increment(1);
+}
+
+pub fn task_failed(event_type: &str) {
+    counter!("herald_bot_tasks_failed_total", "event_type" => event_type.to_string())
+        .increment(1);
+}
+
+pub fn openrouter_cost_usd(cost: f64) {
+    counter!("herald_openrouter_cost_cents_total").increment((cost * 100.0).round() as u64);
+}
+
+pub fn describe() {
+    describe_counter!("herald_webhooks_received_total", Unit::Count, "Total webhooks received");
+    describe_counter!("herald_webhooks_duplicate_total", Unit::Count, "Webhooks rejected as duplicates");
+    describe_counter!("herald_webhooks_channel_full_total", Unit::Count, "Webhooks dropped because the bot channel was full");
+    describe_gauge!("herald_bot_tasks_active", Unit::Count, "Bot tasks currently in progress");
+    describe_counter!("herald_bot_tasks_completed_total", Unit::Count, "Bot tasks completed successfully");
+    describe_counter!("herald_bot_tasks_failed_total", Unit::Count, "Bot tasks that failed");
+    describe_counter!("herald_openrouter_cost_cents_total", Unit::Count, "Total OpenRouter cost in cents (divide by 100 for USD)");
+}
+
+pub fn install(bind_addr: &str) -> anyhow::Result<()> {
+    describe();
+
+    let builder = metrics_exporter_prometheus::PrometheusBuilder::new();
+    builder
+        .with_http_listener(SocketAddr::from_str(bind_addr)?)
+        .install()?;
+
+    tracing::info!(bind_addr, "Prometheus metrics exporter installed");
+    Ok(())
+}