feat(#2470): capture config-approval eval/deploy nix runs in build logs

hive-c0re/src/meta.rs

@@ -238,7 +238,7 @@ pub async fn prepare_deploy(name: &str) -> Result<()> {
     let _guard = META_LOCK.lock().await;
     let dir = crate::paths::meta_root();
     let input = format!("agent-{name}");
-    nix(&dir, &["flake", "update", &input]).await?;
+    nix_logged(&dir, &["flake", "update", &input], name, "prepare-deploy").await?;
     // Stage the new lock — git+file://'s dirty-tree fetcher reads
     // index entries, so the upcoming nixos-container update sees the
     // bumped rev without a commit yet.
@@ -324,7 +324,7 @@ pub async fn verify_commit(name: &str, applied_dir: &Path, sha: &str) -> Result<
     let input = format!("agent-{name}");
     let over = agent_input_override(applied_dir, sha);
     let attr = format!(".#nixosConfigurations.{name}.config.system.build.toplevel.drvPath");
-    nix(
+    nix_logged(
         &dir,
         &[
             "eval",
@@ -334,6 +334,8 @@ pub async fn verify_commit(name: &str, applied_dir: &Path, sha: &str) -> Result<
             &over,
             "--no-write-lock-file",
         ],
+        name,
+        "verify",
     )
     .await
 }
@@ -1308,19 +1310,31 @@ async fn paths_dirty(dir: &Path, paths: &[&str]) -> Result<bool> {
     Ok(!out.status.success())
 }
 
-async fn nix(dir: &Path, args: &[&str]) -> Result<()> {
-    // `--extra-experimental-features` belt-and-suspenders for hosts
-    // that haven't set this in nix.conf. The hyperhive module's
-    // deploy guide assumes flakes are already enabled, but the cost
-    // of being defensive is one extra argv each call.
+/// Full argv for a `nix` invocation, prefixed with the flakes-enabling
+/// experimental-features flag. `--extra-experimental-features` is
+/// belt-and-suspenders for hosts that haven't set this in nix.conf: the
+/// hyperhive module's deploy guide assumes flakes are already enabled,
+/// but the cost of being defensive is one extra argv each call.
+fn nix_argv<'a>(args: &[&'a str]) -> Vec<&'a str> {
     let mut all = vec!["--extra-experimental-features", "nix-command flakes"];
-    all.extend(args);
-    let out = Command::new("nix")
+    all.extend_from_slice(args);
+    all
+}
+
+/// Run `nix <args>` in `dir` (flakes enabled), capturing combined output.
+/// Shared core of [`nix`] and [`nix_logged`].
+async fn nix_output(dir: &Path, args: &[&str]) -> Result<std::process::Output> {
+    Command::new("nix")
         .current_dir(dir)
-        .args(&all)
+        .args(nix_argv(args))
         .output()
         .await
-        .with_context(|| format!("nix {} in {}", args.join(" "), dir.display()))?;
+        .with_context(|| format!("nix {} in {}", args.join(" "), dir.display()))
+}
+
+/// Turn a finished nix [`Output`](std::process::Output) into `Result<()>`,
+/// bailing with the trimmed stderr tail on non-zero exit.
+fn nix_check(args: &[&str], out: &std::process::Output) -> Result<()> {
     if !out.status.success() {
         bail!(
             "nix {} failed ({}): {}",
@@ -1332,6 +1346,52 @@ async fn nix(dir: &Path, args: &[&str]) -> Result<()> {
     Ok(())
 }
 
+async fn nix(dir: &Path, args: &[&str]) -> Result<()> {
+    let out = nix_output(dir, args).await?;
+    nix_check(args, &out)
+}
+
+/// Like [`nix`] but records the invocation (cmdline + stdout + stderr +
+/// terminal status) into a `build_logs.sqlite` row so a config-approval
+/// eval/deploy step shows up on the dashboard. This is what makes a
+/// failing eval-verify visible: it runs before any container build, so
+/// without a row a rejected config approval leaves the operator with
+/// zero build logs to look at. Best-effort logging: a missing global
+/// handle or a failed `start()` just skips the row — the command still
+/// runs and its exit status is still enforced.
+async fn nix_logged(dir: &Path, args: &[&str], agent: &str, kind: &str) -> Result<()> {
+    let cmdline = format!("nix {}", nix_argv(args).join(" "));
+    let logs = crate::build_logs::global();
+    let log_id = logs.as_ref().and_then(|h| {
+        h.start(agent, kind, &cmdline)
+            .map_err(|e| {
+                tracing::warn!(error = ?e, %kind, "build_logs: start failed (meta log dropped)");
+            })
+            .ok()
+    });
+
+    let out = nix_output(dir, args).await?;
+
+    if let (Some(h), Some(id)) = (&logs, log_id) {
+        for line in String::from_utf8_lossy(&out.stdout).lines() {
+            h.append_stdout(id, line);
+        }
+        for line in String::from_utf8_lossy(&out.stderr).lines() {
+            h.append_stderr(id, line);
+        }
+        h.finish(
+            id,
+            if out.status.success() {
+                crate::build_logs::BuildStatus::Ok
+            } else {
+                crate::build_logs::BuildStatus::Fail
+            },
+        );
+    }
+
+    nix_check(args, &out)
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;