Export booted system and kernel hash as well

Cargo.lock

@@ -450,7 +450,7 @@ dependencies = [
 
 [[package]]
 name = "nixos-exporter"
-version = "0.1.0"
+version = "0.3.0"
 dependencies = [
  "axum",
  "reqwest",

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "nixos-exporter"
-version = "0.1.0"
+version = "0.3.0"
 edition = "2021"
 
 [dependencies]

src/main.rs

@@ -1,7 +1,7 @@
 use axum::{
     extract::{State, Query},
     http::StatusCode,
-    response::{IntoResponse, Response},
+    response::IntoResponse,
     routing::get,
     Router,
 };
@@ -59,12 +59,12 @@ impl AppState{
 }
 
 fn parse_nix_store_path(path: std::path::PathBuf) -> Result<(String, String), String> {
-    let (hash, name) = path.file_name()
-        .ok_or_else(String::default)?
+    let (hash, name) = path.iter().nth(3)
+        .ok_or_else(|| String::from("Can't read store path name"))?
         .to_str()
-        .ok_or_else(String::default)?
+        .ok_or_else(|| String::from("Failed converting store path name to string"))?
         .split_once("-")
-        .ok_or_else(String::default)?;
+        .ok_or_else(|| String::from("Failed splitting store path name for hash and name"))?;
     return Ok((hash.to_string(), name.to_string()));
 }
 
@@ -143,114 +143,78 @@ async fn main() {
         .unwrap();
 }
 
-fn get_current_system() -> Result<(String, String), String> {
-    let symlink = match std::fs::read_link("/run/current-system") {
-        Ok(symlink) => symlink,
-        Err(err) => return Err(err.to_string()),
-    };
+fn parse_symlink(path: String) -> Result<(String, String), String> {
+    let symlink = std::fs::read_link(path).map_err(|err| err.to_string())?;
 
     let (hash, name) = parse_nix_store_path(symlink)?;
 
     Ok((String::from(hash), String::from(name)))
 }
 
-async fn metrics() -> Response {
-    let current_system = get_current_system();
-    let (hash, name) = match current_system {
-        Ok((hash, name)) => (hash, name),
-        Err(err) => {
-            println!("failed: {}", err);
-            return (StatusCode::INTERNAL_SERVER_ERROR, "").into_response();
-        }
-    };
+fn gen_prometheus_metric(path: String, infix: String) -> Result<String, String> {
+    let (hash, name) = parse_symlink(path).map_err(|err| err)?;
 
-    (
-        StatusCode::OK,
-        format!("nixos_current_system_hash{{hash=\"{}\"}} 1\nnixos_current_system_name{{name=\"{}\"}} 1\n", hash, name)
-    ).into_response()
+    return Ok(format!("nixos_{}_hash{{hash=\"{}\"}} 1\nnixos_{}_name{{name=\"{}\"}} 1\n", infix, hash, infix, name));
 }
 
-async fn check(State(app_state): State<AppState>, Query(params): Query<HashMap<String, String>>) -> Response {
-    let target = match params.get("target") {
-        Some(target) => target,
-        None => {
-            return (StatusCode::NOT_FOUND, "specify target").into_response();
-        },
-    };
+async fn metrics() -> Result<(StatusCode, impl IntoResponse), (StatusCode, impl IntoResponse)> {
+    let mut out = String::new();
+    out.push_str(&gen_prometheus_metric(String::from("/run/current-system"), String::from("current_system"))
+        .map_err(|err| (StatusCode::INTERNAL_SERVER_ERROR, err))?);
+    out.push_str(&gen_prometheus_metric(String::from("/run/current-system/kernel"), String::from("current_system_kernel"))
+        .map_err(|err| (StatusCode::INTERNAL_SERVER_ERROR, err))?);
+    out.push_str(&gen_prometheus_metric(String::from("/run/booted-system"), String::from("booted_system"))
+        .map_err(|err| (StatusCode::INTERNAL_SERVER_ERROR, err))?);
+    out.push_str(&gen_prometheus_metric(String::from("/run/booted-system/kernel"), String::from("booted_system_kernel"))
+        .map_err(|err| (StatusCode::INTERNAL_SERVER_ERROR, err))?);
+    return Ok((
+        StatusCode::OK,
+        out,
+    ));
+}
+
+async fn check(State(app_state): State<AppState>, Query(params): Query<HashMap<String, String>>) -> Result<(StatusCode, impl IntoResponse), (StatusCode, impl IntoResponse)> {
+    let target = params.get("target")
+        .ok_or_else(|| (StatusCode::NOT_FOUND, "specify target"))?;
 
     if target.contains("\"") {
-        return (StatusCode::INTERNAL_SERVER_ERROR, "Invalid target name").into_response();
+        return Err((StatusCode::INTERNAL_SERVER_ERROR, "Invalid target name"));
     }
 
     let client = reqwest::Client::new();
 
-    let prometheus_req = match client.get(format!("{}/api/v1/query?query=nixos_nixos_current_system_hash{{{}}}", app_state.prometheus_url, app_state.prometheus_query_tag_template.clone().replace("{}", target)))
+    let prometheus_req = client.get(format!("{}/api/v1/query?query=nixos_current_system_hash{{{}}}", app_state.prometheus_url, app_state.prometheus_query_tag_template.clone().replace("{}", target)))
         .header("Accept", "application/json")
-        .send().await {
-            Ok(req) => req,
-            Err(_) => {
-                return (StatusCode::INTERNAL_SERVER_ERROR, "Promehteus can't get reached").into_response();
-            },
-        };
+        .send().await
+        .map_err(|_err| (StatusCode::INTERNAL_SERVER_ERROR, "Promehteus can't get reached"))?;
 
-
-    match prometheus_req.status() {
-        reqwest::StatusCode::OK => (),
-        _ => {
-            return (StatusCode::NOT_FOUND, "Target does not exist in Hydra").into_response();
-        },
+    if prometheus_req.status() != reqwest::StatusCode::OK {
+       return Err((StatusCode::NOT_FOUND, "Target does not exist in Hydra"));
     }
 
-    let prometheus_body = match prometheus_req.json::<serde_json::Value>().await {
-        Ok(body) => body,
-        Err(_) => {
-            return (StatusCode::INTERNAL_SERVER_ERROR, "Invalid response from Hydra").into_response();
-        },
-    };
+    let prometheus_body = prometheus_req.json::<serde_json::Value>().await
+        .map_err(|_err| (StatusCode::INTERNAL_SERVER_ERROR, "Invalid response from Hydra"))?;
 
-    let current_system_hash = match prometheus_body["data"]["result"][0]["metric"]["hash"].as_str() {
-        Some(nix_store_path) => nix_store_path,
-        _ => {
-            return (StatusCode::INTERNAL_SERVER_ERROR, "No buildoutput found in Hydra").into_response();
-        },
-    };
+    let current_system_hash = prometheus_body["data"]["result"][0]["metric"]["hash"].as_str()
+        .ok_or_else(|| (StatusCode::INTERNAL_SERVER_ERROR, "No buildoutput found in Hydra"))?;
 
-    let hydra_req = match client.get(format!("{}/job/{}/latest", app_state.hydra_url, app_state.hydra_job_template.clone().replace("{}", target)))
+    let hydra_req = client.get(format!("{}/job/{}/latest", app_state.hydra_url, app_state.hydra_job_template.clone().replace("{}", target)))
         .header("Accept", "application/json")
-        .send().await {
-            Ok(req) => req,
-            Err(_) => {
-                return (StatusCode::INTERNAL_SERVER_ERROR, "Hydra can't get reached").into_response();
-            },
-        };
+        .send().await
+        .map_err(|_err| (StatusCode::INTERNAL_SERVER_ERROR, "Hydra can't get reached"))?;
 
-    match hydra_req.status() {
-        reqwest::StatusCode::OK => (),
-        _ => {
-            return (StatusCode::NOT_FOUND, "Target does not exist in Hydra").into_response();
-        },
+    if hydra_req.status() != reqwest::StatusCode::OK {
+        return Err((StatusCode::NOT_FOUND, "Target does not exist in Hydra"));
     }
 
-    let hydra_body = match hydra_req.json::<serde_json::Value>().await {
-        Ok(body) => body,
-        Err(_) => {
-            return (StatusCode::INTERNAL_SERVER_ERROR, "Invalid response from Hydra").into_response();
-        },
-    };
+    let hydra_body = hydra_req.json::<serde_json::Value>().await
+        .map_err(|_err| (StatusCode::INTERNAL_SERVER_ERROR, "Invalid response from Hydra"))?;
 
-    let nix_store_path = match hydra_body["buildoutputs"]["out"]["path"].as_str() {
-        Some(nix_store_path) => nix_store_path,
-        _ => {
-            return (StatusCode::INTERNAL_SERVER_ERROR, "No buildoutput found in Hydra").into_response();
-        },
-    };
+    let nix_store_path = hydra_body["buildoutputs"]["out"]["path"].as_str()
+        .ok_or_else(|| (StatusCode::INTERNAL_SERVER_ERROR, "No buildoutput found in Hydra"))?;
 
-    let (hydra_system_hash, _) = match parse_nix_store_path(std::path::PathBuf::from(nix_store_path)) {
-        Ok((hash, name)) => (hash, name),
-        Err(_) => {
-            return (StatusCode::INTERNAL_SERVER_ERROR, "Invalid store path returned by Hydra").into_response();
-        },
-    };
+    let (hydra_system_hash, _) = parse_nix_store_path(std::path::PathBuf::from(nix_store_path))
+        .map_err(|_err| (StatusCode::INTERNAL_SERVER_ERROR, "Invalid store path returned by Hydra"))?;
 
     let mut status = "0";
 
@@ -258,8 +222,8 @@ async fn check(State(app_state): State<AppState>, Query(params): Query<HashMap<S
         status = "1";
     }
 
-    return (
+    return Ok((
         StatusCode::OK,
-        format!("nixos_current_system_valid{{{}}} {}\n", app_state.prometheus_query_tag_template.clone().replace("{}", target), status)
-    ).into_response();
+        format!("nixos_current_system_is_sync{{}} {}\n", status)
+    ));
 }