| 1 | // SPDX-License-Identifier: GPL-3.0-or-later |
| 2 | |
| 3 | package discovery |
| 4 | |
| 5 | import ( |
| 6 | "context" |
| 7 | "errors" |
| 8 | "fmt" |
| 9 | "log/slog" |
| 10 | "sync" |
| 11 | "time" |
| 12 | |
| 13 | "github.com/netdata/netdata/go/plugins/logger" |
| 14 | "github.com/netdata/netdata/go/plugins/plugin/framework/confgroup" |
| 15 | ) |
| 16 | |
| 17 | func NewManager(cfg Config) (*Manager, error) { |
| 18 | if err := validateConfig(cfg); err != nil { |
| 19 | return nil, fmt.Errorf("discovery manager config validation: %v", err) |
| 20 | } |
| 21 | |
| 22 | mgr := &Manager{ |
| 23 | Logger: logger.New().With( |
| 24 | slog.String("component", "discovery manager"), |
| 25 | ), |
| 26 | send: make(chan struct{}, 1), |
| 27 | sendEvery: time.Second * 2, // timeout to aggregate changes |
| 28 | discoverers: make([]Discoverer, 0), |
| 29 | mux: &sync.RWMutex{}, |
| 30 | cache: newCache(), |
| 31 | } |
| 32 | |
| 33 | if err := mgr.registerDiscoverers(cfg); err != nil { |
| 34 | return nil, fmt.Errorf("discovery manager initializaion: %v", err) |
| 35 | } |
| 36 | |
| 37 | return mgr, nil |
| 38 | } |
| 39 | |
| 40 | type Manager struct { |
| 41 | *logger.Logger |
| 42 | discoverers []Discoverer |
| 43 | send chan struct{} |
| 44 | sendEvery time.Duration |
| 45 | mux *sync.RWMutex |
| 46 | cache *cache |
| 47 | } |
| 48 | |
| 49 | func (m *Manager) String() string { |
| 50 | return fmt.Sprintf("discovery manager: %v", m.discoverers) |
| 51 | } |
| 52 | |
| 53 | func (m *Manager) Run(ctx context.Context, in chan<- []*confgroup.Group) { |
| 54 | m.Info("instance is started") |
| 55 | defer func() { m.Info("instance is stopped") }() |
| 56 | |
| 57 | var wg sync.WaitGroup |
| 58 | |
| 59 | for _, d := range m.discoverers { |
| 60 | wg.Add(1) |
| 61 | go func(d Discoverer) { |
| 62 | defer wg.Done() |
| 63 | m.runDiscoverer(ctx, d) |
| 64 | }(d) |
| 65 | } |
| 66 | |
| 67 | wg.Go(func() { |
| 68 | m.sendLoop(ctx, in) |
| 69 | }) |
| 70 | |
| 71 | wg.Wait() |
| 72 | <-ctx.Done() |
| 73 | } |
| 74 | |
| 75 | func (m *Manager) registerDiscoverers(cfg Config) error { |
| 76 | for _, provider := range cfg.Providers { |
| 77 | d, enabled, err := provider.Build(cfg.BuildContext) |
| 78 | if err != nil { |
| 79 | return fmt.Errorf("provider '%s': %w", provider.Name(), err) |
| 80 | } |
| 81 | if !enabled { |
| 82 | continue |
| 83 | } |
| 84 | if d == nil { |
| 85 | return fmt.Errorf("provider '%s': enabled but returned nil discoverer", provider.Name()) |
| 86 | } |
| 87 | m.discoverers = append(m.discoverers, d) |
| 88 | } |
| 89 | |
| 90 | if len(m.discoverers) == 0 { |
| 91 | return errors.New("zero registered discoverers") |
| 92 | } |
| 93 | |
| 94 | m.Infof("registered discoverers: %v", m.discoverers) |
| 95 | |
| 96 | return nil |
| 97 | } |
| 98 | |
| 99 | func (m *Manager) runDiscoverer(ctx context.Context, d Discoverer) { |
| 100 | done := make(chan struct{}) |
| 101 | updates := make(chan []*confgroup.Group) |
| 102 | |
| 103 | go func() { defer close(done); d.Run(ctx, updates) }() |
| 104 | |
| 105 | for { |
| 106 | select { |
| 107 | case <-ctx.Done(): |
| 108 | select { |
| 109 | case <-done: |
| 110 | case <-time.After(time.Second * 10): |
| 111 | } |
| 112 | return |
| 113 | case groups, ok := <-updates: |
| 114 | if !ok { |
| 115 | return |
| 116 | } |
| 117 | func() { |
| 118 | m.mux.Lock() |
| 119 | defer m.mux.Unlock() |
| 120 | |
| 121 | m.cache.update(groups) |
| 122 | m.triggerSend() |
| 123 | }() |
| 124 | } |
| 125 | } |
| 126 | } |
| 127 | |
| 128 | func (m *Manager) sendLoop(ctx context.Context, in chan<- []*confgroup.Group) { |
| 129 | m.mustSend(ctx, in) |
| 130 | |
| 131 | tk := time.NewTicker(m.sendEvery) |
| 132 | defer tk.Stop() |
| 133 | |
| 134 | for { |
| 135 | select { |
| 136 | case <-ctx.Done(): |
| 137 | return |
| 138 | case <-tk.C: |
| 139 | select { |
| 140 | case <-m.send: |
| 141 | m.trySend(in) |
| 142 | default: |
| 143 | } |
| 144 | } |
| 145 | } |
| 146 | } |
| 147 | |
| 148 | func (m *Manager) mustSend(ctx context.Context, in chan<- []*confgroup.Group) { |
| 149 | select { |
| 150 | case <-ctx.Done(): |
| 151 | return |
| 152 | case <-m.send: |
| 153 | m.mux.Lock() |
| 154 | groups := m.cache.groups() |
| 155 | m.cache.reset() |
| 156 | m.mux.Unlock() |
| 157 | |
| 158 | select { |
| 159 | case <-ctx.Done(): |
| 160 | case in <- groups: |
| 161 | } |
| 162 | return |
| 163 | } |
| 164 | } |
| 165 | |
| 166 | func (m *Manager) trySend(in chan<- []*confgroup.Group) { |
| 167 | m.mux.Lock() |
| 168 | defer m.mux.Unlock() |
| 169 | |
| 170 | select { |
| 171 | case in <- m.cache.groups(): |
| 172 | m.cache.reset() |
| 173 | default: |
| 174 | m.triggerSend() |
| 175 | } |
| 176 | } |
| 177 | |
| 178 | func (m *Manager) triggerSend() { |
| 179 | select { |
| 180 | case m.send <- struct{}{}: |
| 181 | default: |
| 182 | } |
| 183 | } |