add prometheus metrics

src/env.rs

@@ -11,6 +11,7 @@ pub struct EnvConfig {
     pub gitea_url: String,
     pub gitea_token: String,
     pub gitea_timeout: u64,
+    pub metrics_bind_addr: Option<String>,
 }
 
 pub fn load_config() -> anyhow::Result<EnvConfig> {
@@ -23,6 +24,7 @@ pub fn load_config() -> anyhow::Result<EnvConfig> {
     let gitea_url = try_get_env("GITEA_URL")?;
     let gitea_token = try_get_env("GITEA_TOKEN")?;
     let gitea_timeout = try_get_env("GITEA_TIMEOUT")?.parse()?;
+    let metrics_bind_addr = std::env::var("METRICS_BIND_ADDR").ok();
 
     Ok(EnvConfig {
         http_port,
@@ -34,6 +36,7 @@ pub fn load_config() -> anyhow::Result<EnvConfig> {
         gitea_url,
         gitea_token,
         gitea_timeout,
+        metrics_bind_addr,
     })
 }