Implement git commit hash tracking for build display

- Add get_git_commit() method to read /var/lib/cm-dashboard/git-commit
- Replace NixOS build version with actual git commit hash
- Show deployed commit hash as 'Build:' value for accurate tracking
- Enable verification of which exact commit is deployed per host
- Update version to 0.1.42

Cargo.lock

@@ -270,7 +270,7 @@ checksum = "a1d728cc89cf3aee9ff92b05e62b19ee65a02b5702cff7d5a377e32c6ae29d8d"
 
 [[package]]
 name = "cm-dashboard"
-version = "0.1.33"
+version = "0.1.40"
 dependencies = [
  "anyhow",
  "chrono",
@@ -291,7 +291,7 @@ dependencies = [
 
 [[package]]
 name = "cm-dashboard-agent"
-version = "0.1.33"
+version = "0.1.40"
 dependencies = [
  "anyhow",
  "async-trait",
@@ -314,7 +314,7 @@ dependencies = [
 
 [[package]]
 name = "cm-dashboard-shared"
-version = "0.1.33"
+version = "0.1.40"
 dependencies = [
  "chrono",
  "serde",

agent/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "cm-dashboard-agent"
-version = "0.1.34"
+version = "0.1.42"
 edition = "2021"
 
 [dependencies]

agent/src/collectors/nixos.rs

@@ -37,6 +37,22 @@ impl NixOSCollector {
     }
 
     /// Get configuration hash from deployed nix store system
+    /// Get git commit hash from rebuild process
+    fn get_git_commit(&self) -> Result<String, Box<dyn std::error::Error>> {
+        let commit_file = "/var/lib/cm-dashboard/git-commit";
+        match std::fs::read_to_string(commit_file) {
+            Ok(content) => {
+                let commit_hash = content.trim();
+                if commit_hash.len() >= 7 {
+                    Ok(commit_hash.to_string())
+                } else {
+                    Err("Git commit hash too short".into())
+                }
+            }
+            Err(e) => Err(format!("Failed to read git commit file: {}", e).into())
+        }
+    }
+
     fn get_config_hash(&self) -> Result<String, Box<dyn std::error::Error>> {
         // Read the symlink target of /run/current-system to get nix store path
         let output = Command::new("readlink")
@@ -74,25 +90,25 @@ impl Collector for NixOSCollector {
         let mut metrics = Vec::new();
         let timestamp = chrono::Utc::now().timestamp() as u64;
 
-        // Collect NixOS build information (config hash)
-        match self.get_config_hash() {
-            Ok(config_hash) => {
+        // Collect git commit information (shows what's actually deployed)
+        match self.get_git_commit() {
+            Ok(git_commit) => {
                 metrics.push(Metric {
                     name: "system_nixos_build".to_string(),
-                    value: MetricValue::String(config_hash),
+                    value: MetricValue::String(git_commit),
                     unit: None,
-                    description: Some("NixOS deployed configuration hash".to_string()),
+                    description: Some("Git commit hash of deployed configuration".to_string()),
                     status: Status::Ok,
                     timestamp,
                 });
             }
             Err(e) => {
-                debug!("Failed to get config hash: {}", e);
+                debug!("Failed to get git commit: {}", e);
                 metrics.push(Metric {
                     name: "system_nixos_build".to_string(),
                     value: MetricValue::String("unknown".to_string()),
                     unit: None,
-                    description: Some("NixOS config hash (failed to detect)".to_string()),
+                    description: Some("Git commit hash (failed to detect)".to_string()),
                     status: Status::Unknown,
                     timestamp,
                 });

agent/src/collectors/systemd.rs

@@ -555,10 +555,8 @@ impl SystemdCollector {
         for (site_name, url) in &sites {
             match self.check_site_latency(url) {
                 Ok(latency_ms) => {
-                    let status = if latency_ms < 500.0 {
+                    let status = if latency_ms < self.config.nginx_latency_critical_ms {
                         Status::Ok
-                    } else if latency_ms < 2000.0 {
-                        Status::Warning
                     } else {
                         Status::Critical
                     };

agent/src/config/mod.rs

@@ -108,6 +108,7 @@ pub struct SystemdConfig {
     pub nginx_check_interval_seconds: u64,
     pub http_timeout_seconds: u64,
     pub http_connect_timeout_seconds: u64,
+    pub nginx_latency_critical_ms: f32,
 }
 
 

agent/src/config/validation.rs

@@ -83,6 +83,13 @@ pub fn validate_config(config: &AgentConfig) -> Result<()> {
         }
     }
 
+    // Validate systemd configuration
+    if config.collectors.systemd.enabled {
+        if config.collectors.systemd.nginx_latency_critical_ms <= 0.0 {
+            bail!("Nginx latency critical threshold must be positive");
+        }
+    }
+
     // Validate SMTP configuration
     if config.notifications.enabled {
         if config.notifications.smtp_host.is_empty() {

dashboard/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "cm-dashboard"
-version = "0.1.34"
+version = "0.1.42"
 edition = "2021"
 
 [dependencies]

dashboard/src/main.rs

@@ -14,7 +14,7 @@ use app::Dashboard;
 
 /// Get hardcoded version
 fn get_version() -> &'static str {
-    "v0.1.33"
+    "v0.1.42"
 }
 
 /// Check if running inside tmux session

dashboard/src/ui/mod.rs

@@ -244,16 +244,23 @@ impl TuiApp {
                 KeyCode::Char('r') => {
                     // System rebuild command - works on any panel for current host
                     if let Some(hostname) = self.current_host.clone() {
-                        // Launch tmux popup with SSH using config values
-                        let ssh_command = format!(
-                            "ssh -tt {}@{} 'bash -ic {}'",
+                        // Create command that shows CM Dashboard logo and then rebuilds
+                        let logo_and_rebuild = format!(
+                            r"cat << 'EOF'
+NixOS System Rebuild
+Target: {}
+
+EOF
+ssh -tt {}@{} 'bash -ic {}'",
+                            hostname,
                             self.config.ssh.rebuild_user,
                             hostname,
                             self.config.ssh.rebuild_alias
                         );
+                        
                         std::process::Command::new("tmux")
                             .arg("display-popup")
-                            .arg(&ssh_command)
+                            .arg(&logo_and_rebuild)
                             .spawn()
                             .ok(); // Ignore errors, tmux will handle them
                     }
@@ -536,48 +543,87 @@ impl TuiApp {
 
         if self.available_hosts.is_empty() {
             let title_text = "cm-dashboard • no hosts discovered";
-            let title = Paragraph::new(title_text).style(Typography::title());
+            let title = Paragraph::new(title_text)
+                .style(Style::default().fg(Theme::background()).bg(Theme::status_color(Status::Unknown)));
             frame.render_widget(title, area);
             return;
         }
 
-        // Create spans for each host with status indicators
-        let mut spans = vec![Span::styled("cm-dashboard • ", Typography::title())];
+        // Calculate worst-case status across all hosts
+        let mut worst_status = Status::Ok;
+        for host in &self.available_hosts {
+            let host_status = self.calculate_host_status(host, metric_store);
+            worst_status = Status::aggregate(&[worst_status, host_status]);
+        }
 
+        // Use the worst status color as background
+        let background_color = Theme::status_color(worst_status);
+
+        // Split the title bar into left and right sections
+        let chunks = Layout::default()
+            .direction(Direction::Horizontal)
+            .constraints([Constraint::Length(15), Constraint::Min(0)])
+            .split(area);
+
+        // Left side: "cm-dashboard" text
+        let left_span = Span::styled(
+            " cm-dashboard", 
+            Style::default().fg(Theme::background()).bg(background_color).add_modifier(Modifier::BOLD)
+        );
+        let left_title = Paragraph::new(Line::from(vec![left_span]))
+            .style(Style::default().bg(background_color));
+        frame.render_widget(left_title, chunks[0]);
+
+        // Right side: hosts with status indicators
+        let mut host_spans = Vec::new();
+        
         for (i, host) in self.available_hosts.iter().enumerate() {
             if i > 0 {
-                spans.push(Span::styled(" ", Typography::title()));
+                host_spans.push(Span::styled(
+                    " ", 
+                    Style::default().fg(Theme::background()).bg(background_color)
+                ));
             }
 
             // Always show normal status icon based on metrics (no command status at host level)
             let host_status = self.calculate_host_status(host, metric_store);
-            let (status_icon, status_color) = (StatusIcons::get_icon(host_status), Theme::status_color(host_status));
+            let status_icon = StatusIcons::get_icon(host_status);
 
-            // Add status icon
-            spans.push(Span::styled(
+            // Add status icon with background color as foreground against status background
+            host_spans.push(Span::styled(
                 format!("{} ", status_icon),
-                Style::default().fg(status_color),
+                Style::default().fg(Theme::background()).bg(background_color),
             ));
 
             if Some(host) == self.current_host.as_ref() {
-                // Selected host in bold bright white
-                spans.push(Span::styled(
+                // Selected host in bold background color against status background
+                host_spans.push(Span::styled(
                     host.clone(),
-                    Typography::title().add_modifier(Modifier::BOLD),
+                    Style::default()
+                        .fg(Theme::background())
+                        .bg(background_color)
+                        .add_modifier(Modifier::BOLD),
                 ));
             } else {
-                // Other hosts in normal style with status color
-                spans.push(Span::styled(
+                // Other hosts in normal background color against status background
+                host_spans.push(Span::styled(
                     host.clone(),
-                    Style::default().fg(status_color),
+                    Style::default().fg(Theme::background()).bg(background_color),
                 ));
             }
         }
 
-        let title_line = Line::from(spans);
-        let title = Paragraph::new(vec![title_line]);
+        // Add right padding
+        host_spans.push(Span::styled(
+            " ", 
+            Style::default().fg(Theme::background()).bg(background_color)
+        ));
 
-        frame.render_widget(title, area);
+        let host_line = Line::from(host_spans);
+        let host_title = Paragraph::new(vec![host_line])
+            .style(Style::default().bg(background_color))
+            .alignment(ratatui::layout::Alignment::Right);
+        frame.render_widget(host_title, chunks[1]);
     }
 
     /// Calculate overall status for a host based on its metrics
@@ -662,7 +708,7 @@ impl TuiApp {
                 host_widgets.system_scroll_offset
             };
             let host_widgets = self.get_or_create_host_widgets(&hostname);
-            host_widgets.system_widget.render_with_scroll(frame, inner_area, scroll_offset);
+            host_widgets.system_widget.render_with_scroll(frame, inner_area, scroll_offset, &hostname);
         }
     }
 

dashboard/src/ui/theme.rs

@@ -292,12 +292,6 @@ impl Components {
 }
 
 impl Typography {
-    /// Main title style (dashboard header)
-    pub fn title() -> Style {
-        Style::default()
-            .fg(Theme::primary_text())
-            .bg(Theme::background())
-    }
 
     /// Widget title style (panel headers) - bold bright white
     pub fn widget_title() -> Style {

dashboard/src/ui/widgets/system.rs

@@ -230,9 +230,30 @@ impl SystemWidget {
 
     /// Extract pool name from disk metric name
     fn extract_pool_name(&self, metric_name: &str) -> Option<String> {
-        if let Some(captures) = metric_name.strip_prefix("disk_") {
-            if let Some(pos) = captures.find('_') {
-                return Some(captures[..pos].to_string());
+        // Pattern: disk_{pool_name}_{drive_name}_{metric_type}
+        // Since pool_name can contain underscores, work backwards from known metric suffixes
+        if metric_name.starts_with("disk_") {
+            // First try drive-specific metrics that have device names
+            if let Some(suffix_pos) = metric_name.rfind("_temperature")
+                .or_else(|| metric_name.rfind("_wear_percent"))
+                .or_else(|| metric_name.rfind("_health")) {
+                // Find the second-to-last underscore to get pool name
+                let before_suffix = &metric_name[..suffix_pos];
+                if let Some(drive_start) = before_suffix.rfind('_') {
+                    return Some(metric_name[5..drive_start].to_string()); // Skip "disk_"
+                }
+            }
+            // For pool-level metrics (usage_percent, used_gb, total_gb), take everything before the metric suffix
+            else if let Some(suffix_pos) = metric_name.rfind("_usage_percent")
+                .or_else(|| metric_name.rfind("_used_gb"))
+                .or_else(|| metric_name.rfind("_total_gb")) {
+                return Some(metric_name[5..suffix_pos].to_string()); // Skip "disk_"
+            }
+            // Fallback to old behavior for unknown patterns
+            else if let Some(captures) = metric_name.strip_prefix("disk_") {
+                if let Some(pos) = captures.find('_') {
+                    return Some(captures[..pos].to_string());
+                }
             }
         }
         None
@@ -240,10 +261,18 @@ impl SystemWidget {
 
     /// Extract drive name from disk metric name  
     fn extract_drive_name(&self, metric_name: &str) -> Option<String> {
-        // Pattern: disk_pool_drive_metric
-        let parts: Vec<&str> = metric_name.split('_').collect();
-        if parts.len() >= 3 && parts[0] == "disk" {
-            return Some(parts[2].to_string());
+        // Pattern: disk_{pool_name}_{drive_name}_{metric_type}
+        // Since pool_name can contain underscores, work backwards from known metric suffixes
+        if metric_name.starts_with("disk_") {
+            if let Some(suffix_pos) = metric_name.rfind("_temperature")
+                .or_else(|| metric_name.rfind("_wear_percent"))
+                .or_else(|| metric_name.rfind("_health")) {
+                // Find the second-to-last underscore to get the drive name
+                let before_suffix = &metric_name[..suffix_pos];
+                if let Some(drive_start) = before_suffix.rfind('_') {
+                    return Some(before_suffix[drive_start + 1..].to_string());
+                }
+            }
         }
         None
     }
@@ -410,12 +439,12 @@ impl Widget for SystemWidget {
 
 impl SystemWidget {
     /// Render with scroll offset support
-    pub fn render_with_scroll(&mut self, frame: &mut Frame, area: Rect, scroll_offset: usize) {
+    pub fn render_with_scroll(&mut self, frame: &mut Frame, area: Rect, scroll_offset: usize, hostname: &str) {
         let mut lines = Vec::new();
 
         // NixOS section
         lines.push(Line::from(vec![
-            Span::styled("NixOS:", Typography::widget_title())
+            Span::styled(format!("NixOS {}:", hostname), Typography::widget_title())
         ]));
         
         let build_text = self.nixos_build.as_deref().unwrap_or("unknown");

shared/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "cm-dashboard-shared"
-version = "0.1.34"
+version = "0.1.42"
 edition = "2021"
 
 [dependencies]