From c2687b44edb4da3b258f4e28c6add8713c50bcec Mon Sep 17 00:00:00 2001
From: Jesper Jensen <jesper@jnsn.dev>
Date: Fri, 6 Feb 2026 19:34:39 +0100
Subject: Add metrics

---
 src/metrics.rs | 147 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 147 insertions(+)
 create mode 100644 src/metrics.rs

(limited to 'src/metrics.rs')

diff --git a/src/metrics.rs b/src/metrics.rs
new file mode 100644
index 0000000..09617c4
--- /dev/null
+++ b/src/metrics.rs
@@ -0,0 +1,147 @@
+use prometheus::{
+    CounterVec, Gauge, HistogramVec,
+    Opts, Registry, TextEncoder, Encoder,
+    histogram_opts,
+};
+use std::sync::OnceLock;
+use std::thread;
+
+pub const STATE_IDLE: f64 = 0.0;
+pub const STATE_ACTIVE: f64 = 1.0;
+pub const STATE_THROTTLED: f64 = 2.0;
+
+pub static METRICS: OnceLock<Metrics> = OnceLock::new();
+
+pub fn get() -> &'static Metrics {
+    METRICS.get().unwrap()
+}
+
+pub struct Metrics {
+    pub state: Gauge,
+    pub images_checked: CounterVec,
+    pub images_updated: CounterVec,
+    pub http_request: CounterVec,
+    pub http_request_duration: HistogramVec,
+    pub rate_limits: CounterVec,
+    pub auth_attempts: CounterVec,
+    pub run_duration: Gauge,
+    pub git_operations: CounterVec,
+    registry: Registry,
+}
+
+impl Metrics {
+    pub fn new() -> Self {
+        let registry = Registry::new();
+
+        let state = Gauge::with_opts(
+            Opts::new("vbump_state", "Current state: 0=idle, 1=active, 2=throttled"),
+        ).unwrap();
+        registry.register(Box::new(state.clone())).unwrap();
+
+        let images_checked = CounterVec::new(
+            Opts::new("vbump_images_checked_total", "Total images checked"),
+            &["registry"],
+        ).unwrap();
+        registry.register(Box::new(images_checked.clone())).unwrap();
+
+        let images_updated = CounterVec::new(
+            Opts::new("vbump_images_updated_total", "Total images with newer versions found"),
+            &["registry"],
+        ).unwrap();
+        registry.register(Box::new(images_updated.clone())).unwrap();
+
+        let http_request = CounterVec::new(
+            Opts::new("vbump_http_request_total", "Total HTTP requests to registries"),
+            &["registry", "outcome"],
+        ).unwrap();
+        registry.register(Box::new(http_request.clone())).unwrap();
+
+        let http_request_duration = HistogramVec::new(
+            histogram_opts!(
+                "vbump_http_request_duration_seconds",
+                "Request latency distribution",
+                vec![0.01, 0.025, 0.05, 0.1, 0.25, 0.5, 1.0, 2.5, 5.0, 10.0]
+            ),
+            &["registry"],
+        ).unwrap();
+        registry.register(Box::new(http_request_duration.clone())).unwrap();
+
+        let rate_limits = CounterVec::new(
+            Opts::new("vbump_rate_limits_total", "Rate limit (429) responses received"),
+            &["registry"],
+        ).unwrap();
+        registry.register(Box::new(rate_limits.clone())).unwrap();
+
+        let auth_attempts = CounterVec::new(
+            Opts::new("vbump_auth_attempts_total", "Auth attempts (success/failure)"),
+            &["registry", "outcome"],
+        ).unwrap();
+        registry.register(Box::new(auth_attempts.clone())).unwrap();
+
+        let run_duration = Gauge::with_opts(
+            Opts::new("vbump_run_duration_seconds", "Duration of last complete scan"),
+        ).unwrap();
+        registry.register(Box::new(run_duration.clone())).unwrap();
+
+        let git_operations = CounterVec::new(
+            Opts::new("vbump_git_operations_total", "Git commits/pushes (success/failure)"),
+            &["operation", "outcome"],
+        ).unwrap();
+        registry.register(Box::new(git_operations.clone())).unwrap();
+
+        Self {
+            state,
+            images_checked,
+            images_updated,
+            http_request,
+            http_request_duration,
+            rate_limits,
+            auth_attempts,
+            run_duration,
+            git_operations,
+            registry,
+        }
+    }
+}
+
+pub fn init() {
+    METRICS.get_or_init(Metrics::new);
+}
+
+pub fn serve(port: u16) {
+    let registry = get().registry.clone();
+
+    thread::spawn(move || {
+        let addr = format!("0.0.0.0:{}", port);
+        let server = match tiny_http::Server::http(&addr) {
+            Ok(s) => s,
+            Err(e) => {
+                eprintln!("Failed to start metrics server on {}: {}", addr, e);
+                return;
+            }
+        };
+        println!("Metrics server listening on {}", addr);
+
+        for request in server.incoming_requests() {
+            let response = if request.url() == "/metrics" {
+                let encoder = TextEncoder::new();
+                let metric_families = registry.gather();
+                let mut buffer = Vec::new();
+                encoder.encode(&metric_families, &mut buffer).unwrap();
+
+                tiny_http::Response::from_data(buffer)
+                    .with_header(
+                        tiny_http::Header::from_bytes(
+                            &b"Content-Type"[..],
+                            &b"text/plain; version=0.0.4; charset=utf-8"[..],
+                        ).unwrap()
+                    )
+            } else {
+                tiny_http::Response::from_string("Not Found")
+                    .with_status_code(404)
+            };
+
+            let _ = request.respond(response);
+        }
+    });
+}
-- 
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