fluxcd / flux2

API Endpoints for fluxcd/flux2

FluxCD/Flux2: Defined Routes Documentation

This documentation page focuses on the defined routes within the FluxCD/Flux2 codebase. As expert developers, you are expected to leverage this information to navigate, modify, or extend functionality within the code.

Overview of Routing in FluxCD/Flux2

In the FluxCD/Flux2 project, routing is typically established through Go HTTP handlers or through declarative configurations expressed in Kubernetes manifests. The codebase leverages external libraries such as github.com/gorilla/mux for routing when handling HTTP requests.

Directing Requests Through mux

The github.com/gorilla/mux package is a powerful URL router and dispatcher for Golang. It allows for flexible routing mechanisms based on HTTP methods, paths, and parameters.

Example Route Definition

A simple route can be defined as follows:

import (
"github.com/gorilla/mux"
"net/http"
)

func main() {
r := mux.NewRouter()

r.HandleFunc("/api/v1/resources", getResourcesHandler).Methods("GET")
r.HandleFunc("/api/v1/resource/{id}", getResourceHandler).Methods("GET")

http.ListenAndServe(":8080", r)
}

// Sample handler functions
func getResourcesHandler(w http.ResponseWriter, r *http.Request) {
// Handle the request
}

func getResourceHandler(w http.ResponseWriter, r *http.Request) {
// Handle the request based on resource ID
}

Parameter Matching

Routes can also capture parameters from URLs:

r.HandleFunc("/api/v1/resource/{id}", func(w http.ResponseWriter, r *http.Request) {
vars := mux.Vars(r)
id := vars["id"]
// Use the extracted ID
}).Methods("GET")

Kubernetes Declarative Approach

In addition to HTTP routing, FluxCD declares its management routes through Kubernetes resources, such as Custom Resource Definitions (CRDs) and Controllers. Manifests define the expected behavior of deployed entities.

Example YAML for a Resource

The following example illustrates a Network Policy that could affect traffic routing among pods:

apiVersion: networking.k8s.io/v1
kind: NetworkPolicy
metadata:
name: allow-egress
spec:
policyTypes:
- Ingress
- Egress
ingress:
- from:
- podSelector: {}
egress:
- {}
podSelector: {}

This policy defines rules that dictate how pods communicate within the network, thereby managing the routes that defined services can use to communicate with each other.

Additional Considerations

When scrutinizing the routes:

  1. Handler Functions: Pay attention to the handler functions for various routes in cmd/flux/*.go. These functions define the logic that is executed when a specific route is hit.

  2. RBAC Policies: Consider the role-based access control (RBAC) configurations present in manifests/rbac/controller.yaml. These configurations can impact accessibility to certain routes based on user roles.

  3. Test Constraints: During testing, the flux2 codebase incorporates build constraints that determine which tests run (e.g., “unit” and “e2e”). It’s pertinent to analyze how this may affect route accessibility in different environments.

Conclusion

This documentation should serve as a foundational overview of the routes defined within the FluxCD/Flux2 codebase. By leveraging the mux router and the declarative approach of Kubernetes manifests, developers can create, modify, or extend the functionality of the FluxCD application within Kubernetes environments.

References

  • Source of routing information can be found in handler implementations and route definitions throughout the codebase, particularly in files under cmd/flux/*.go and the usage of github.com/gorilla/mux.
  • Kubernetes resource definitions illustrate route management via RBAC and Network Policies.

Sources