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packages/system/kubernetes/README.md
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packages/system/kubernetes/README.md
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# SAL Kubernetes (`sal-kubernetes`)
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Kubernetes cluster management and operations for the System Abstraction Layer (SAL).
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## Installation
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Add this to your `Cargo.toml`:
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```toml
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[dependencies]
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sal-kubernetes = "0.1.0"
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```
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## ⚠️ **IMPORTANT SECURITY NOTICE**
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**This package includes destructive operations that can permanently delete Kubernetes resources!**
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- The `delete(pattern)` function uses PCRE regex patterns to bulk delete resources
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- **Always test patterns in a safe environment first**
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- Use specific patterns to avoid accidental deletion of critical resources
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- Consider the impact on dependent resources before deletion
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- **No confirmation prompts** - deletions are immediate and irreversible
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## Overview
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This package provides a high-level interface for managing Kubernetes clusters using the `kube-rs` SDK. It focuses on namespace-scoped operations through the `KubernetesManager` factory pattern.
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### Production Safety Features
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- **Configurable Timeouts**: All operations have configurable timeouts to prevent hanging
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- **Exponential Backoff Retry**: Automatic retry logic for transient failures
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- **Rate Limiting**: Built-in rate limiting to prevent API overload
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- **Comprehensive Error Handling**: Detailed error types and proper error propagation
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- **Structured Logging**: Production-ready logging for monitoring and debugging
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## Features
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- **Application Deployment**: Deploy complete applications with a single method call
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- **Environment Variables & Labels**: Configure containers with environment variables and Kubernetes labels
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- **Resource Lifecycle Management**: Automatic cleanup and replacement of existing resources
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- **Namespace-scoped Management**: Each `KubernetesManager` instance operates on a single namespace
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- **Pod Management**: List, create, and manage pods
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- **Pattern-based Deletion**: Delete resources using PCRE pattern matching
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- **Namespace Operations**: Create and manage namespaces (idempotent operations)
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- **Resource Management**: Support for pods, services, deployments, configmaps, secrets, and more
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- **Rhai Integration**: Full scripting support through Rhai wrappers with environment variables
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## Core Concepts
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### Labels vs Environment Variables
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Understanding the difference between labels and environment variables is crucial for effective Kubernetes deployments:
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#### **Labels** (Kubernetes Metadata)
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- **Purpose**: Organize, select, and manage Kubernetes resources
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- **Scope**: Kubernetes cluster management and resource organization
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- **Visibility**: Used by Kubernetes controllers, selectors, and monitoring systems
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- **Examples**: `app=my-app`, `tier=backend`, `environment=production`, `version=v1.2.3`
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- **Use Cases**: Resource grouping, service discovery, monitoring labels, deployment strategies
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#### **Environment Variables** (Container Configuration)
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- **Purpose**: Configure application runtime behavior and settings
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- **Scope**: Inside container processes - available to your application code
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- **Visibility**: Accessible via `process.env`, `os.environ`, etc. in your application
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- **Examples**: `NODE_ENV=production`, `DATABASE_URL=postgres://...`, `API_KEY=secret`
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- **Use Cases**: Database connections, API keys, feature flags, runtime configuration
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#### **Example: Complete Application Configuration**
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```rust
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// Labels: For Kubernetes resource management
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let mut labels = HashMap::new();
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labels.insert("app".to_string(), "web-api".to_string()); // Service discovery
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labels.insert("tier".to_string(), "backend".to_string()); // Architecture layer
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labels.insert("environment".to_string(), "production".to_string()); // Deployment stage
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labels.insert("version".to_string(), "v2.1.0".to_string()); // Release version
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// Environment Variables: For application configuration
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let mut env_vars = HashMap::new();
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env_vars.insert("NODE_ENV".to_string(), "production".to_string()); // Runtime mode
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env_vars.insert("DATABASE_URL".to_string(), "postgres://db:5432/app".to_string()); // DB connection
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env_vars.insert("REDIS_URL".to_string(), "redis://cache:6379".to_string()); // Cache connection
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env_vars.insert("LOG_LEVEL".to_string(), "info".to_string()); // Logging config
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```
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## Usage
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### Application Deployment (Recommended)
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Deploy complete applications with labels and environment variables:
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```rust
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use sal_kubernetes::KubernetesManager;
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use std::collections::HashMap;
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#[tokio::main]
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async fn main() -> Result<(), Box<dyn std::error::Error>> {
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let km = KubernetesManager::new("default").await?;
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// Configure labels for Kubernetes resource organization
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let mut labels = HashMap::new();
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labels.insert("app".to_string(), "my-app".to_string());
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labels.insert("tier".to_string(), "backend".to_string());
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// Configure environment variables for the container
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let mut env_vars = HashMap::new();
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env_vars.insert("NODE_ENV".to_string(), "production".to_string());
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env_vars.insert("DATABASE_URL".to_string(), "postgres://db:5432/myapp".to_string());
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env_vars.insert("API_KEY".to_string(), "secret-api-key".to_string());
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// Deploy application with deployment + service
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km.deploy_application(
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"my-app", // name
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"node:18-alpine", // image
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3, // replicas
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3000, // port
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Some(labels), // Kubernetes labels
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Some(env_vars), // container environment variables
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).await?;
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println!("✅ Application deployed successfully!");
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Ok(())
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}
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```
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### Basic Operations
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```rust
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use sal_kubernetes::KubernetesManager;
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#[tokio::main]
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async fn main() -> Result<(), Box<dyn std::error::Error>> {
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// Create a manager for the "default" namespace
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let km = KubernetesManager::new("default").await?;
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// List all pods in the namespace
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let pods = km.pods_list().await?;
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println!("Found {} pods", pods.len());
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// Create a namespace (no error if it already exists)
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km.namespace_create("my-namespace").await?;
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// Delete resources matching a pattern
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km.delete("test-.*").await?;
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Ok(())
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}
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```
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### Rhai Scripting
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```javascript
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// Create Kubernetes manager for namespace
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let km = kubernetes_manager_new("default");
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// Deploy application with labels and environment variables
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deploy_application(km, "my-app", "node:18-alpine", 3, 3000, #{
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"app": "my-app",
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"tier": "backend",
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"environment": "production"
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}, #{
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"NODE_ENV": "production",
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"DATABASE_URL": "postgres://db:5432/myapp",
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"API_KEY": "secret-api-key"
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});
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print("✅ Application deployed!");
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// Basic operations
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let pods = pods_list(km);
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print("Found " + pods.len() + " pods");
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namespace_create(km, "my-namespace");
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delete(km, "test-.*");
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```
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## Dependencies
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- `kube`: Kubernetes client library
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- `k8s-openapi`: Kubernetes API types
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- `tokio`: Async runtime
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- `regex`: Pattern matching for resource deletion
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- `rhai`: Scripting integration (optional)
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## Configuration
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### Kubernetes Authentication
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The package uses the standard Kubernetes configuration methods:
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- In-cluster configuration (when running in a pod)
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- Kubeconfig file (`~/.kube/config` or `KUBECONFIG` environment variable)
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- Service account tokens
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### Production Safety Configuration
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```rust
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use sal_kubernetes::{KubernetesManager, KubernetesConfig};
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use std::time::Duration;
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// Create with custom configuration
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let config = KubernetesConfig::new()
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.with_timeout(Duration::from_secs(60))
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.with_retries(5, Duration::from_secs(1), Duration::from_secs(30))
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.with_rate_limit(20, 50);
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let km = KubernetesManager::with_config("my-namespace", config).await?;
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```
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### Pre-configured Profiles
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```rust
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// High-throughput environment
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let config = KubernetesConfig::high_throughput();
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// Low-latency environment
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let config = KubernetesConfig::low_latency();
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// Development/testing
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let config = KubernetesConfig::development();
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```
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## Error Handling
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All operations return `Result<T, KubernetesError>` with comprehensive error types for different failure scenarios including API errors, configuration issues, and permission problems.
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## API Reference
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### KubernetesManager
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The main interface for Kubernetes operations. Each instance is scoped to a single namespace.
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#### Constructor
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- `KubernetesManager::new(namespace)` - Create a manager for the specified namespace
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#### Application Deployment
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- `deploy_application(name, image, replicas, port, labels, env_vars)` - Deploy complete application with deployment and service
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- `deployment_create(name, image, replicas, labels, env_vars)` - Create deployment with environment variables and labels
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#### Resource Creation
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- `pod_create(name, image, labels, env_vars)` - Create pod with environment variables and labels
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- `service_create(name, selector, port, target_port)` - Create service with port mapping
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- `configmap_create(name, data)` - Create configmap with data
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- `secret_create(name, data, secret_type)` - Create secret with data and optional type
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#### Resource Listing
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- `pods_list()` - List all pods in the namespace
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- `services_list()` - List all services in the namespace
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- `deployments_list()` - List all deployments in the namespace
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- `configmaps_list()` - List all configmaps in the namespace
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- `secrets_list()` - List all secrets in the namespace
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#### Resource Management
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- `pod_get(name)` - Get a specific pod by name
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- `service_get(name)` - Get a specific service by name
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- `deployment_get(name)` - Get a specific deployment by name
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- `pod_delete(name)` - Delete a specific pod by name
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- `service_delete(name)` - Delete a specific service by name
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- `deployment_delete(name)` - Delete a specific deployment by name
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- `configmap_delete(name)` - Delete a specific configmap by name
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- `secret_delete(name)` - Delete a specific secret by name
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#### Pattern-based Operations
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- `delete(pattern)` - Delete all resources matching a PCRE pattern
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#### Namespace Operations
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- `namespace_create(name)` - Create a namespace (idempotent)
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- `namespace_exists(name)` - Check if a namespace exists
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- `namespaces_list()` - List all namespaces (cluster-wide)
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#### Utility Functions
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- `resource_counts()` - Get counts of all resource types in the namespace
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- `namespace()` - Get the namespace this manager operates on
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### Rhai Functions
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When using the Rhai integration, the following functions are available:
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**Manager Creation & Application Deployment:**
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- `kubernetes_manager_new(namespace)` - Create a KubernetesManager
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- `deploy_application(km, name, image, replicas, port, labels, env_vars)` - Deploy application with environment variables
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**Resource Listing:**
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- `pods_list(km)` - List pods
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- `services_list(km)` - List services
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- `deployments_list(km)` - List deployments
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- `configmaps_list(km)` - List configmaps
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- `secrets_list(km)` - List secrets
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- `namespaces_list(km)` - List all namespaces
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- `resource_counts(km)` - Get resource counts
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**Resource Operations:**
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- `delete(km, pattern)` - Delete resources matching pattern
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- `pod_delete(km, name)` - Delete specific pod
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- `service_delete(km, name)` - Delete specific service
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- `deployment_delete(km, name)` - Delete specific deployment
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- `configmap_delete(km, name)` - Delete specific configmap
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- `secret_delete(km, name)` - Delete specific secret
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**Namespace Functions:**
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- `namespace_create(km, name)` - Create namespace
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- `namespace_exists(km, name)` - Check namespace existence
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- `namespace_delete(km, name)` - Delete namespace
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- `namespace(km)` - Get manager's namespace
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## Examples
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The `examples/kubernetes/clusters/` directory contains comprehensive examples:
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### Rust Examples
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Run with: `cargo run --example <name> --features kubernetes`
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- `postgres` - PostgreSQL database deployment with environment variables
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- `redis` - Redis cache deployment with configuration
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- `generic` - Multiple application deployments (nginx, node.js, mongodb)
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### Rhai Examples
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Run with: `./target/debug/herodo examples/kubernetes/clusters/<script>.rhai`
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- `postgres.rhai` - PostgreSQL cluster deployment script
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- `redis.rhai` - Redis cluster deployment script
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### Real-World Examples
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#### PostgreSQL Database
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```rust
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let mut env_vars = HashMap::new();
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env_vars.insert("POSTGRES_DB".to_string(), "myapp".to_string());
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env_vars.insert("POSTGRES_USER".to_string(), "postgres".to_string());
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env_vars.insert("POSTGRES_PASSWORD".to_string(), "secretpassword".to_string());
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km.deploy_application("postgres", "postgres:15", 1, 5432, Some(labels), Some(env_vars)).await?;
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```
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#### Redis Cache
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```rust
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let mut env_vars = HashMap::new();
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env_vars.insert("REDIS_PASSWORD".to_string(), "redispassword".to_string());
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env_vars.insert("REDIS_MAXMEMORY".to_string(), "256mb".to_string());
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km.deploy_application("redis", "redis:7-alpine", 3, 6379, None, Some(env_vars)).await?;
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```
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## Testing
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### Test Coverage
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The module includes comprehensive test coverage:
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- **Unit Tests**: Core functionality without cluster dependency
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- **Integration Tests**: Real Kubernetes cluster operations
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- **Environment Variables Tests**: Complete env var functionality testing
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- **Edge Cases Tests**: Error handling and boundary conditions
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- **Rhai Integration Tests**: Scripting environment testing
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- **Production Readiness Tests**: Concurrent operations and error handling
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### Running Tests
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```bash
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# Unit tests (no cluster required)
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cargo test --package sal-kubernetes
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# Integration tests (requires cluster)
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KUBERNETES_TEST_ENABLED=1 cargo test --package sal-kubernetes
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# Rhai integration tests
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KUBERNETES_TEST_ENABLED=1 cargo test --package sal-kubernetes --features rhai
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# Run specific test suites
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cargo test --package sal-kubernetes deployment_env_vars_test
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cargo test --package sal-kubernetes edge_cases_test
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# Rhai environment variables test
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KUBERNETES_TEST_ENABLED=1 ./target/debug/herodo kubernetes/tests/rhai/env_vars_test.rhai
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```
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### Test Requirements
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- **Kubernetes Cluster**: Integration tests require a running Kubernetes cluster
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- **Environment Variable**: Set `KUBERNETES_TEST_ENABLED=1` to enable integration tests
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- **Permissions**: Tests require permissions to create/delete resources in the `default` namespace
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## Production Considerations
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### Security
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- Always use specific PCRE patterns to avoid accidental deletion of important resources
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- Test deletion patterns in a safe environment first
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- Ensure proper RBAC permissions are configured
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- Be cautious with cluster-wide operations like namespace listing
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- Use Kubernetes secrets for sensitive environment variables instead of plain text
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### Performance & Scalability
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- Consider adding resource limits (CPU/memory) for production deployments
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- Use persistent volumes for stateful applications
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- Configure readiness and liveness probes for health checks
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- Implement proper monitoring and logging labels
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### Environment Variables Best Practices
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- Use Kubernetes secrets for sensitive data (passwords, API keys)
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- Validate environment variable values before deployment
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- Use consistent naming conventions (e.g., `DATABASE_URL`, `API_KEY`)
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- Document required vs optional environment variables
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### Example: Production-Ready Deployment
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```rust
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// Production labels for monitoring and management
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let mut labels = HashMap::new();
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labels.insert("app".to_string(), "web-api".to_string());
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labels.insert("version".to_string(), "v1.2.3".to_string());
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labels.insert("environment".to_string(), "production".to_string());
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labels.insert("team".to_string(), "backend".to_string());
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// Non-sensitive environment variables
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let mut env_vars = HashMap::new();
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env_vars.insert("NODE_ENV".to_string(), "production".to_string());
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env_vars.insert("LOG_LEVEL".to_string(), "info".to_string());
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env_vars.insert("PORT".to_string(), "3000".to_string());
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// Note: Use Kubernetes secrets for DATABASE_URL, API_KEY, etc.
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km.deploy_application("web-api", "myapp:v1.2.3", 3, 3000, Some(labels), Some(env_vars)).await?;
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```
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