feat: add optional OpenCost cost awareness

Cargo.toml

@@ -45,6 +45,7 @@ anyhow = "1"
 # Serialization
 serde = { version = "1", features = ["derive"] }
 serde_json = "1"
+reqwest = { version = "0.12", default-features = false, features = ["json", "rustls-tls"] }
 
 # CLI args + shell completions + man page generation
 clap = { version = "4", features = ["derive"] }

README.md

@@ -15,6 +15,7 @@
 - **Live watch** — resources appear and update in real time as the cluster changes; deleted resources show `[DELETED]`
 - **Unhealthy-first ordering** — `CrashLoopBackOff`, `Error`, `ImagePullBackOff` pods surface to the top automatically
 - **Color-coded status** — red for critical, yellow for warning, green for healthy, dimmed for deleted
+- **Optional OpenCost column** — show per-pod / per-controller cost inline, with namespace or cluster aggregate in the header
 - **Multi-select bulk actions** — `tab` to select multiple resources, then describe/delete/restart them all at once
 - **Multi-cluster support** — watch all kubeconfig contexts simultaneously with `--all-contexts`, or switch contexts interactively with `ctrl-x`
 - **Context persistence** — last-used context is remembered across sessions
@@ -202,10 +203,34 @@ kf --kubeconfig ~/alt.yaml --context staging  # use an alternate kubeconfig
 
 ---
 
+## Optional Cost Awareness
+
+Create `~/.config/kuberift/config.toml`:
+
+```toml
+[cost]
+enabled = true
+opencost_endpoint = ""      # optional manual override; empty = auto-discover in cluster
+display_period = "daily"    # hourly | daily | monthly
+highlight_threshold = 10.0  # highlight resources above $/day
+```
+
+When cost mode is enabled, `kf` will:
+
+- detect `opencost` / `kubecost` services and query `allocation/compute`
+- map pod allocations onto pods and controller-backed resources
+- render a cost column without changing existing actions or output format
+- disable cost for the current session if the endpoint is missing, slow, or unreachable
+
+The namespace filter (`-n production`) also shows the namespace aggregate in the header.
+
+---
+
 ## Config & State
 
 | File | Purpose |
 |------|---------|
+| `~/.config/kuberift/config.toml` | Optional settings (`[cost]`) for OpenCost integration |
 | `~/.config/kuberift/last_context` | Last-used context, restored on next launch |
 | `$XDG_RUNTIME_DIR/<pid>/preview-mode` | Preview mode state (0=describe, 1=yaml, 2=logs) |
 | `$XDG_RUNTIME_DIR/<pid>/preview-toggle` | Shell script installed at startup for ctrl-p |

src/config.rs

@@ -0,0 +1,70 @@
+use serde::Deserialize;
+use std::path::{Path, PathBuf};
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Deserialize, Default)]
+#[serde(rename_all = "lowercase")]
+pub enum CostDisplayPeriod {
+    Hourly,
+    #[default]
+    Daily,
+    Monthly,
+}
+
+#[derive(Debug, Clone, Deserialize)]
+pub struct CostConfig {
+    #[serde(default)]
+    pub enabled: bool,
+    #[serde(default)]
+    pub opencost_endpoint: String,
+    #[serde(default)]
+    pub display_period: CostDisplayPeriod,
+    #[serde(default = "default_highlight_threshold")]
+    pub highlight_threshold: f64,
+}
+
+impl Default for CostConfig {
+    fn default() -> Self {
+        Self {
+            enabled: false,
+            opencost_endpoint: String::new(),
+            display_period: CostDisplayPeriod::Daily,
+            highlight_threshold: default_highlight_threshold(),
+        }
+    }
+}
+
+#[derive(Debug, Clone, Deserialize, Default)]
+pub struct AppConfig {
+    #[serde(default)]
+    pub cost: CostConfig,
+}
+
+fn default_highlight_threshold() -> f64 {
+    10.0
+}
+
+pub fn config_file_path() -> Option<PathBuf> {
+    dirs::config_dir().map(|dir| dir.join("kuberift").join("config.toml"))
+}
+
+pub fn load_config() -> AppConfig {
+    config_file_path()
+        .as_deref()
+        .and_then(load_config_from_path)
+        .unwrap_or_default()
+}
+
+pub fn load_config_from_path(path: &Path) -> Option<AppConfig> {
+    let raw = std::fs::read_to_string(path).ok()?;
+    Some(parse_config(&raw, path))
+}
+
+pub fn parse_config(raw: &str, source: &Path) -> AppConfig {
+    toml::from_str(raw).unwrap_or_else(|err| {
+        eprintln!(
+            "[kuberift] warning: cannot parse config '{}': {err}",
+            source.display()
+        );
+        AppConfig::default()
+    })
+}