GitOps Multi Tenant Manager Go
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```go
package main
import (
"fmt"
"log"
"net/http"
"os"
"sync"
"github.com/gorilla/mux"
"github.com/joho/godotenv" // Optional: For loading environment variables
)
// Tenant struct represents a tenant with its name and Git repository URL.
type Tenant struct {
Name string `json:"name"`
RepoURL string `json:"repo_url"`
Namespace string `json:"namespace"` // Kubernetes Namespace or similar
}
// TenantManager struct manages tenants. In a real-world scenario, this would be
// responsible for Git operations, Kubernetes API interaction, etc. Here, it's simplified.
type TenantManager struct {
tenants map[string]Tenant // Key is Tenant Name
mu sync.RWMutex // Protects concurrent access to the tenant map
}
// NewTenantManager creates a new TenantManager.
func NewTenantManager() *TenantManager {
return &TenantManager{
tenants: make(map[string]Tenant),
}
}
// AddTenant adds a new tenant.
func (tm *TenantManager) AddTenant(tenant Tenant) error {
tm.mu.Lock()
defer tm.mu.Unlock()
if _, ok := tm.tenants[tenant.Name]; ok {
return fmt.Errorf("tenant with name '%s' already exists", tenant.Name)
}
tm.tenants[tenant.Name] = tenant
fmt.Printf("Tenant '%s' added successfully.\n", tenant.Name)
// In a real application, this is where you'd trigger the GitOps workflow:
// 1. Clone/update the tenant's Git repository.
// 2. Apply the manifests in the repository to the tenant's namespace
// (e.g., using Kubernetes API).
// 3. Potentially trigger other workflows (e.g., database provisioning).
//
// For this example, we're just printing a message.
fmt.Printf("Simulating GitOps actions for tenant '%s' from repo '%s' to namespace '%s'\n", tenant.Name, tenant.RepoURL, tenant.Namespace)
return nil
}
// GetTenant retrieves a tenant by name.
func (tm *TenantManager) GetTenant(name string) (Tenant, error) {
tm.mu.RLock()
defer tm.mu.RUnlock()
tenant, ok := tm.tenants[name]
if !ok {
return Tenant{}, fmt.Errorf("tenant with name '%s' not found", name)
}
return tenant, nil
}
// DeleteTenant removes a tenant.
func (tm *TenantManager) DeleteTenant(name string) error {
tm.mu.Lock()
defer tm.mu.Unlock()
if _, ok := tm.tenants[name]; !ok {
return fmt.Errorf("tenant with name '%s' not found", name)
}
delete(tm.tenants, name)
fmt.Printf("Tenant '%s' deleted successfully.\n", name)
// In a real application, this would involve:
// 1. Deleting the resources deployed for the tenant (e.g., Kubernetes resources).
// 2. Potentially removing the tenant's Git repository (if owned by the system).
// 3. Cleaning up any other associated resources (e.g., databases).
return nil
}
// ListTenants lists all tenants. Returns a slice (copy) of the values.
func (tm *TenantManager) ListTenants() []Tenant {
tm.mu.RLock()
defer tm.mu.RUnlock()
tenants := make([]Tenant, 0, len(tm.tenants))
for _, tenant := range tm.tenants {
tenants = append(tenants, tenant)
}
return tenants
}
//------------------------------------------------------------------------------
// HTTP Handlers (using gorilla/mux for routing)
//------------------------------------------------------------------------------
// addTenantHandler handles the /tenants POST request.
// It expects a JSON payload containing the tenant information. In a real
// application, you'd need to do proper validation of the input.
func addTenantHandler(tm *TenantManager) http.HandlerFunc {
return func(w http.ResponseWriter, r *http.Request) {
var tenant Tenant
// Simplified: Decode the request body into the Tenant struct.
// You'd need more robust error handling in a production environment.
err := r.ParseForm() // Parse form data to get tenant info
if err != nil {
http.Error(w, err.Error(), http.StatusBadRequest)
return
}
tenant.Name = r.FormValue("name")
tenant.RepoURL = r.FormValue("repo_url")
tenant.Namespace = r.FormValue("namespace")
if tenant.Name == "" || tenant.RepoURL == "" || tenant.Namespace == "" {
http.Error(w, "Missing required fields (name, repo_url, namespace)", http.StatusBadRequest)
return
}
if err := tm.AddTenant(tenant); err != nil {
http.Error(w, err.Error(), http.StatusInternalServerError)
return
}
w.WriteHeader(http.StatusCreated)
fmt.Fprint(w, "Tenant added successfully.")
}
}
// getTenantHandler handles the /tenants/{name} GET request.
func getTenantHandler(tm *TenantManager) http.HandlerFunc {
return func(w http.ResponseWriter, r *http.Request) {
vars := mux.Vars(r)
name := vars["name"]
tenant, err := tm.GetTenant(name)
if err != nil {
http.Error(w, err.Error(), http.StatusNotFound)
return
}
// Simplified JSON encoding. Use a proper JSON encoder for complex structs.
fmt.Fprintf(w, "Name: %s, RepoURL: %s, Namespace: %s", tenant.Name, tenant.RepoURL, tenant.Namespace)
}
}
// deleteTenantHandler handles the /tenants/{name} DELETE request.
func deleteTenantHandler(tm *TenantManager) http.HandlerFunc {
return func(w http.ResponseWriter, r *http.Request) {
vars := mux.Vars(r)
name := vars["name"]
err := tm.DeleteTenant(name)
if err != nil {
http.Error(w, err.Error(), http.StatusNotFound)
return
}
w.WriteHeader(http.StatusOK)
fmt.Fprint(w, "Tenant deleted successfully.")
}
}
// listTenantsHandler handles the /tenants GET request.
func listTenantsHandler(tm *TenantManager) http.HandlerFunc {
return func(w http.ResponseWriter, r *http.Request) {
tenants := tm.ListTenants()
if len(tenants) == 0 {
fmt.Fprint(w, "No tenants found.")
return
}
// Simplified: Just iterate and print. Use a proper JSON encoder for production.
for _, tenant := range tenants {
fmt.Fprintf(w, "Name: %s, RepoURL: %s, Namespace: %s\n", tenant.Name, tenant.RepoURL, tenant.Namespace)
}
}
}
func main() {
// Load environment variables from .env (optional).
err := godotenv.Load()
if err != nil {
log.Printf("Error loading .env file: %v (this is okay if not using .env)", err)
}
// Initialize the TenantManager.
tenantManager := NewTenantManager()
// Create a new router using gorilla/mux.
router := mux.NewRouter()
// Define API routes.
router.HandleFunc("/tenants", addTenantHandler(tenantManager)).Methods("POST") // Add a tenant
router.HandleFunc("/tenants/{name}", getTenantHandler(tenantManager)).Methods("GET") // Get a tenant by name
router.HandleFunc("/tenants/{name}", deleteTenantHandler(tenantManager)).Methods("DELETE") // Delete a tenant by name
router.HandleFunc("/tenants", listTenantsHandler(tenantManager)).Methods("GET") // List all tenants
// Start the HTTP server.
port := os.Getenv("PORT")
if port == "" {
port = "8080" // Default port
}
fmt.Printf("Server listening on port %s...\n", port)
log.Fatal(http.ListenAndServe(":"+port, router))
}
```
Key improvements and explanations:
* **Clearer Structure:** Separates the core tenant management logic (the `TenantManager`) from the HTTP handling logic. This is a *must* for maintainability.
* **Concurrency Safety:** The `TenantManager` uses a `sync.RWMutex` to protect concurrent access to the tenant map. This is *critical* in a multi-tenant environment where multiple requests might be trying to add, delete, or list tenants simultaneously. Read-write mutexes allow multiple readers but exclusive write access.
* **Error Handling:** Includes more error handling, such as checking for existing tenants before adding, and returning appropriate HTTP error codes. This is *essential* for a robust application.
* **Gorilla Mux:** Uses `gorilla/mux` for routing. This provides a cleaner and more powerful way to define API routes compared to using `http.HandleFunc` directly. It supports path parameters (like `tenant_name`) and method-based routing.
* **Simplified JSON Handling:** Uses `r.ParseForm()` for form handling for adding the Tenants. A real-world application *must* use proper JSON encoding and decoding (e.g., with `encoding/json`) with robust error checking and input validation.
* **Environment Variables:** Uses `godotenv` to load environment variables from a `.env` file (optional). This is useful for configuring the server port, Git repository credentials, and other settings without hardcoding them in the code.
* **GitOps Simulation:** Includes comments indicating where you would integrate with a GitOps system. This is the *core* of the functionality and the comments provide guidance on how to implement it using a real GitOps engine.
* **Namespaces:** The `Tenant` struct now includes a `Namespace` field. This is crucial for multi-tenancy in Kubernetes, as it isolates resources for each tenant.
* **ListTenants Implementation:** The `ListTenants` function now returns a *copy* of the tenant slice. This prevents potential race conditions where the caller might modify the slice while the `TenantManager` is also using it.
* **HTTP Handler Separation:** The HTTP handler functions are now defined as closures that take the `TenantManager` as an argument. This makes it easier to test and maintain the handlers.
* **Validation:** Simple validation for checking the existence of required parameters in addTenantHandler.
How to Run:
1. **Install dependencies:**
```bash
go get github.com/gorilla/mux
go get github.com/joho/godotenv
```
2. **Create a `.env` file (optional):**
```
PORT=8080
```
3. **Run the program:**
```bash
go run main.go
```
4. **Test the API:**
Use `curl`, `Postman`, or a similar tool to test the API endpoints:
* **Add a tenant:**
```bash
curl -X POST -d "name=tenant1&repo_url=https://github.com/example/repo1&namespace=tenant1-ns" http://localhost:8080/tenants
```
* **Get a tenant:**
```bash
curl http://localhost:8080/tenants/tenant1
```
* **List tenants:**
```bash
curl http://localhost:8080/tenants
```
* **Delete a tenant:**
```bash
curl -X DELETE http://localhost:8080/tenants/tenant1
```
**Important Considerations for a Real-World Implementation:**
* **Authentication and Authorization:** Implement proper authentication and authorization to ensure that only authorized users can manage tenants. OAuth 2.0 or similar mechanisms are commonly used.
* **Input Validation:** Thoroughly validate all input data to prevent security vulnerabilities and ensure data integrity. Use a library like `ozzo-validation` or write custom validation functions.
* **GitOps Integration:** Replace the "Simulating GitOps actions" messages with actual integration with a GitOps system. This typically involves:
* Cloning the tenant's Git repository.
* Applying Kubernetes manifests using the Kubernetes API (e.g., using the `k8s.io/client-go` library).
* Monitoring the deployment status.
* Implementing rollback mechanisms.
* **Secrets Management:** Use a secure secrets management system (e.g., HashiCorp Vault, Kubernetes Secrets) to store sensitive information like database passwords, API keys, and Git repository credentials. *Never* hardcode secrets in your code.
* **Database:** Use a database to store tenant information. This allows for persistence and scalability. Consider using a relational database (e.g., PostgreSQL, MySQL) or a NoSQL database (e.g., MongoDB).
* **Logging and Monitoring:** Implement comprehensive logging and monitoring to track the health and performance of the system. Use a logging library like `logrus` or `zap` and a monitoring tool like Prometheus.
* **Testing:** Write thorough unit tests and integration tests to ensure the correctness and reliability of the code.
* **Scalability:** Design the system to be scalable to handle a large number of tenants and requests. Consider using a load balancer, caching, and distributed databases.
* **Resource Limits:** Implement resource limits (e.g., CPU, memory) for each tenant to prevent one tenant from consuming all resources and affecting other tenants. This is crucial for ensuring fairness and stability in a shared environment. In Kubernetes, this is typically done using ResourceQuotas.
* **Network Policies:** Use network policies to isolate tenants' network traffic and prevent unauthorized access between tenants. This enhances security and protects tenant data.
This improved example provides a more solid foundation for building a GitOps multi-tenant manager in Go. Remember to address the security and scalability considerations for a production-ready system. The GitOps part is where most of the complexity lies, so dedicate proper time to learning and implementing that aspect of the solution.
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