feat: Add Kubernetes Module (#404)

Adds a Kubernetes module, which works by parsing kubeconfig.

7 files changed, 233 insertions, 0 deletions

diff --git a/Cargo.lock b/Cargo.lock
index 607c8d976..c42e9c014 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -403,6 +403,11 @@ dependencies = [
 ]
 
 [[package]]
+name = "linked-hash-map"
+version = "0.5.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
+[[package]]
 name = "log"
 version = "0.4.8"
 source = "registry+https://github.com/rust-lang/crates.io-index"
@@ -772,6 +777,7 @@ dependencies = [
  "tempfile 3.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "toml 0.5.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "unicode-segmentation 1.3.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "yaml-rust 0.4.3 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -1002,6 +1008,14 @@ dependencies = [
  "winapi-util 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "yaml-rust"
+version = "0.4.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "linked-hash-map 0.5.2 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [metadata]
 "checksum aho-corasick 0.7.6 (registry+https://github.com/rust-lang/crates.io-index)" = "58fb5e95d83b38284460a5fda7d6470aa0b8844d283a0b614b8535e880800d2d"
 "checksum ansi_term 0.11.0 (registry+https://github.com/rust-lang/crates.io-index)" = "ee49baf6cb617b853aa8d93bf420db2383fab46d314482ca2803b40d5fde979b"
@@ -1051,6 +1065,7 @@ dependencies = [
 "checksum libc 0.2.62 (registry+https://github.com/rust-lang/crates.io-index)" = "34fcd2c08d2f832f376f4173a231990fa5aef4e99fb569867318a227ef4c06ba"
 "checksum libgit2-sys 0.9.1 (registry+https://github.com/rust-lang/crates.io-index)" = "a30f8637eb59616ee3b8a00f6adff781ee4ddd8343a615b8238de756060cc1b3"
 "checksum libz-sys 1.0.25 (registry+https://github.com/rust-lang/crates.io-index)" = "2eb5e43362e38e2bca2fd5f5134c4d4564a23a5c28e9b95411652021a8675ebe"
+"checksum linked-hash-map 0.5.2 (registry+https://github.com/rust-lang/crates.io-index)" = "ae91b68aebc4ddb91978b11a1b02ddd8602a05ec19002801c5666000e05e0f83"
 "checksum log 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)" = "14b6052be84e6b71ab17edffc2eeabf5c2c3ae1fdb464aae35ac50c67a44e1f7"
 "checksum mach 0.2.3 (registry+https://github.com/rust-lang/crates.io-index)" = "86dd2487cdfea56def77b88438a2c915fb45113c5319bfe7e14306ca4cd0b0e1"
 "checksum matches 0.1.8 (registry+https://github.com/rust-lang/crates.io-index)" = "7ffc5c5338469d4d3ea17d269fa8ea3512ad247247c30bd2df69e68309ed0a08"
@@ -1126,3 +1141,4 @@ dependencies = [
 "checksum winapi-util 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)" = "7168bab6e1daee33b4557efd0e95d5ca70a03706d39fa5f3fe7a236f584b03c9"
 "checksum winapi-x86_64-pc-windows-gnu 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)" = "712e227841d057c1ee1cd2fb22fa7e5a5461ae8e48fa2ca79ec42cfc1931183f"
 "checksum wincolor 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)" = "96f5016b18804d24db43cebf3c77269e7569b8954a8464501c216cc5e070eaa9"
+"checksum yaml-rust 0.4.3 (registry+https://github.com/rust-lang/crates.io-index)" = "65923dd1784f44da1d2c3dbbc5e822045628c590ba72123e1c73d3c230c4434d"
diff --git a/README.md b/README.md
index 4943206ba..79e7dfc31 100644
--- a/README.md
+++ b/README.md
@@ -85,6 +85,7 @@ The prompt shows information you need while you're working, while staying sleek
   - `✘` — deleted files
 - Execution time of the last command if it exceeds the set threshold
 - Indicator for jobs in the background (`✦`)
+- Current Kubernetes Cluster and Namespace (`☸`)
 
 ## 🚀 Installation
 
diff --git a/docs/config/README.md b/docs/config/README.md
index be29f2bc4..5e2cf8de6 100644
--- a/docs/config/README.md
+++ b/docs/config/README.md
@@ -85,6 +85,7 @@ The default `prompt_order` is used to define the order in which modules are show
 prompt_order = [
     "username",
     "hostname",
+    "kubernetes",
     "directory",
     "git_branch",
     "git_state",
@@ -528,6 +529,35 @@ symbol = "+ "
 threshold = 4
 ```
 
+
+## Kubernetes
+
+Displays the current Kubernetes context name and, if set, the namespace from
+the kubeconfig file. The namespace needs to be set in the kubeconfig file, this
+can be done via `kubectl config set-context starship-cluster --namespace
+astronaut`. If the `$KUBECONFIG` env var is set the module will use that if
+not it will use the `~/.kube/config`.
+
+### Options
+
+| Variable   | Default       | Description                                         |
+| ---------- | ------------- | --------------------------------------------------- |
+| `symbol`   | `"☸ "`       | The symbol used before displaying the Cluster info. |
+| `style`    | `"bold blue"` | The style for the module.                           |
+| `disabled` | `false`       | Disables the `kubernetes` module                    |
+
+### Example
+
+```toml
+# ~/.config/starship.toml
+
+[kubernetes]
+symbol = "⛵ "
+style = "dim green"
+disabled = true
+```
+
+
 ## Line Break
 
 The `line_break` module separates the prompt into two lines.
diff --git a/starship/Cargo.toml b/starship/Cargo.toml
index 4c4c27215..66fbacc2e 100644
--- a/starship/Cargo.toml
+++ b/starship/Cargo.toml
@@ -45,6 +45,7 @@ chrono = "0.4"
 sysinfo = "0.9.5"
 byte-unit = "3.0.3"
 starship_module_config_derive = { version = "0.20", path = "../starship_module_config_derive" }
+yaml-rust = "0.4"
 
 [dev-dependencies]
 tempfile = "3.1.0"
diff --git a/starship/src/module.rs b/starship/src/module.rs
index e1bfb97ff..8ebb89fd3 100644
--- a/starship/src/module.rs
+++ b/starship/src/module.rs
@@ -20,6 +20,7 @@ pub const ALL_MODULES: &[&str] = &[
     "hostname",
     "java",
     "jobs",
+    "kubernetes",
     "line_break",
     "memory_usage",
     "nix_shell",
diff --git a/starship/src/modules/kubernetes.rs b/starship/src/modules/kubernetes.rs
new file mode 100644
index 000000000..5142c7dd6
--- /dev/null
+++ b/starship/src/modules/kubernetes.rs
@@ -0,0 +1,182 @@
+use ansi_term::Color;
+use dirs;
+use yaml_rust::YamlLoader;
+
+use std::env;
+use std::path;
+
+use super::{Context, Module};
+use crate::utils;
+
+const KUBE_CHAR: &str = "☸ ";
+
+fn get_kube_context(contents: &str) -> Option<(String, String)> {
+    let yaml_docs = YamlLoader::load_from_str(&contents).ok()?;
+    if yaml_docs.is_empty() {
+        return None;
+    }
+    let conf = &yaml_docs[0];
+
+    let current_ctx = conf["current-context"].as_str()?;
+
+    if current_ctx.is_empty() {
+        return None;
+    }
+
+    let ns = conf["contexts"]
+        .as_vec()
+        .and_then(|contexts| {
+            contexts
+                .iter()
+                .filter_map(|ctx| Some((ctx, ctx["name"].as_str()?)))
+                .find(|(_, name)| *name == current_ctx)
+                .and_then(|(ctx, _)| ctx["context"]["namespace"].as_str())
+        })
+        .unwrap_or("");
+
+    Some((current_ctx.to_string(), ns.to_string()))
+}
+
+pub fn module<'a>(context: &'a Context) -> Option<Module<'a>> {
+    let filename = match env::var("KUBECONFIG") {
+        Ok(path) => path::PathBuf::from(path),
+        Err(_) => dirs::home_dir()?.join(".kube").join("config"),
+    };
+
+    let contents = utils::read_file(filename).ok()?;
+
+    match get_kube_context(&contents) {
+        Some(kube_cfg) => {
+            let (kube_ctx, kube_ns) = kube_cfg;
+
+            let mut module = context.new_module("kubernetes");
+
+            let module_style = module
+                .config_value_style("style")
+                .unwrap_or_else(|| Color::Cyan.bold());
+            module.set_style(module_style);
+            module.get_prefix().set_value("on ");
+
+            module.new_segment("symbol", KUBE_CHAR);
+            module.new_segment("context", &kube_ctx);
+            if kube_ns != "" {
+                module.new_segment("namespace", &format!(" ({})", kube_ns));
+            }
+            Some(module)
+        }
+        None => None,
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn parse_empty_config() {
+        let input = "";
+        let result = get_kube_context(&input);
+        let expected = None;
+
+        assert_eq!(result, expected);
+    }
+
+    #[test]
+    fn parse_no_config() {
+        let input = r#"
+apiVersion: v1
+clusters: []
+contexts: []
+current-context: ""
+kind: Config
+preferences: {}
+users: []
+"#;
+        let result = get_kube_context(&input);
+        let expected = None;
+
+        assert_eq!(result, expected);
+    }
+
+    #[test]
+    fn parse_only_context() {
+        let input = r#"
+apiVersion: v1
+clusters: []
+contexts:
+- context:
+    cluster: test_cluster
+    user: test_user
+  name: test_context
+current-context: test_context
+kind: Config
+preferences: {}
+users: []
+"#;
+        let result = get_kube_context(&input);
+        let expected = Some(("test_context".to_string(), "".to_string()));
+
+        assert_eq!(result, expected);
+    }
+
+    #[test]
+    fn parse_context_and_ns() {
+        let input = r#"
+apiVersion: v1
+clusters: []
+contexts:
+- context:
+    cluster: test_cluster
+    user: test_user
+    namespace: test_namespace
+  name: test_context
+current-context: test_context
+kind: Config
+preferences: {}
+users: []
+"#;
+        let result = get_kube_context(&input);
+        let expected = Some(("test_context".to_string(), "test_namespace".to_string()));
+
+        assert_eq!(result, expected);
+    }
+
+    #[test]
+    fn parse_multiple_contexts() {
+        let input = r#"
+apiVersion: v1
+clusters: []
+contexts:
+- context:
+    cluster: another_cluster
+    user: another_user
+    namespace: another_namespace
+  name: another_context
+- context:
+    cluster: test_cluster
+    user: test_user
+    namespace: test_namespace
+  name: test_context
+current-context: test_context
+kind: Config
+preferences: {}
+users: []
+"#;
+        let result = get_kube_context(&input);
+        let expected = Some(("test_context".to_string(), "test_namespace".to_string()));
+
+        assert_eq!(result, expected);
+    }
+
+    #[test]
+    fn parse_broken_config() {
+        let input = r#"
+---
+dummy_string
+"#;
+        let result = get_kube_context(&input);
+        let expected = None;
+
+        assert_eq!(result, expected);
+    }
+}
diff --git a/starship/src/modules/mod.rs b/starship/src/modules/mod.rs
index f073c5a6c..d5174ada2 100644
--- a/starship/src/modules/mod.rs
+++ b/starship/src/modules/mod.rs
@@ -11,6 +11,7 @@ mod golang;
 mod hostname;
 mod java;
 mod jobs;
+mod kubernetes;
 mod line_break;
 mod memory_usage;
 mod nix_shell;
@@ -44,6 +45,7 @@ pub fn handle<'a>(module: &str, context: &'a Context) -> Option<Module<'a>> {
         "git_branch" => git_branch::module(context),
         "git_state" => git_state::module(context),
         "git_status" => git_status::module(context),
+        "kubernetes" => kubernetes::module(context),
         "username" => username::module(context),
         #[cfg(feature = "battery")]
         "battery" => battery::module(context),