Tyler King
6058e62348
Go-based network automation with YANG models, gRPC, Ansible, Terraform, and Kubernetes integration. Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
76 lines
1.8 KiB
Go
76 lines
1.8 KiB
Go
package topology
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import (
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"encoding/json"
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"fmt"
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"os"
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"sync"
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)
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// Store provides thread-safe access to the mesh topology state.
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// The DaemonSet writes topology updates, and the CNI plugin reads them.
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// State is persisted to a JSON file on disk.
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type Store struct {
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mu sync.RWMutex
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filePath string
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topo *MeshTopology
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}
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// NewStore creates a topology store backed by the given file path.
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func NewStore(filePath string) *Store {
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return &Store{
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filePath: filePath,
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topo: &MeshTopology{},
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}
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}
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// LoadFromFile reads a MeshTopology from a JSON file.
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// Used by the CNI plugin to read the DaemonSet-written state.
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func LoadFromFile(path string) (*MeshTopology, error) {
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data, err := os.ReadFile(path)
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if err != nil {
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return nil, fmt.Errorf("failed to read topology file %s: %w", path, err)
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}
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var topo MeshTopology
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if err := json.Unmarshal(data, &topo); err != nil {
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return nil, fmt.Errorf("failed to parse topology file: %w", err)
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}
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return &topo, nil
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}
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// Get returns a copy of the current topology.
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func (s *Store) Get() MeshTopology {
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s.mu.RLock()
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defer s.mu.RUnlock()
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return *s.topo
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}
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// Update atomically updates the topology and persists to disk.
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func (s *Store) Update(fn func(*MeshTopology)) error {
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s.mu.Lock()
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defer s.mu.Unlock()
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fn(s.topo)
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return s.persist()
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}
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func (s *Store) persist() error {
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data, err := json.MarshalIndent(s.topo, "", " ")
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if err != nil {
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return fmt.Errorf("failed to marshal topology: %w", err)
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}
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// Atomic write: write to temp file, then rename.
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tmpPath := s.filePath + ".tmp"
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if err := os.WriteFile(tmpPath, data, 0644); err != nil {
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return fmt.Errorf("failed to write topology file: %w", err)
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}
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if err := os.Rename(tmpPath, s.filePath); err != nil {
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return fmt.Errorf("failed to rename topology file: %w", err)
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}
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return nil
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}
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