Implemented dynamic configuration reloading for gocast via SIGHUP signal handling. This allows updating BGP configuration, applications, and agent settings without service restart.
**Location:** `main.go:29-46`
Enhanced the existing signal handler to process SIGHUP:
```go
switch sig {
case syscall.SIGHUP:
log.Info("Received SIGHUP, reloading configuration")
if err := mon.Reload(*config); err != nil {
log.Errorf("Failed to reload configuration: %v", err)
} else {
log.Info("Configuration reloaded successfully")
}
case os.Interrupt, syscall.SIGTERM:
log.Info("Received shutdown signal, cleaning up")
mon.CloseAll()
cancel()
return
}
```
**Key Features:**
- Non-blocking: Uses goroutine to handle signals
- Graceful: SIGINT/SIGTERM still trigger clean shutdown
- Logged: All reload attempts are logged with success/failure status
**Location:** `controller/monitor.go:343-420`
Main reload orchestration method:
```go
func (m *MonitorMgr) Reload(configPath string) error
```
**Process Flow:**
1. Read new configuration from file
2. Compare with current configuration
3. If BGP config changed:
- Withdraw all announced routes
- Shutdown old BGP controller
- Start new BGP controller
- Re-announce routes for healthy apps
4. If Consul config changed:
- Initialize new Consul monitor
5. Update agent settings
6. Reload applications (add/remove/update)
**Thread Safety:**
- Uses existing `monMu` mutex for monitor map access
- Atomic BGP controller replacement
- No race conditions during reload
**Location:** `controller/monitor.go:422-475`
```go
func (m *MonitorMgr) bgpConfigChanged(old, new c.BgpConfig) bool
```
Comprehensive comparison of:
- Local AS, Peer AS, Peer IPs
- BGP origin
- Multi-hop settings (including nil checks)
- MD5 passwords and environment variables
- Per-peer communities
- Global communities
**Important:** Deep comparison ensures even minor changes are detected.
**Location:** `controller/monitor.go:477-532`
```go
func (m *MonitorMgr) reloadApps(oldApps, newApps []c.AppConfig)
```
Intelligent app management:
- **Remove:** Apps no longer in config (source="config" only)
- **Update:** Apps with changed configuration (VIP, monitors, NAT, communities)
- **Add:** New apps in configuration
**Key Behavior:**
- Consul-discovered apps are NOT removed during reload
- Only config-defined apps are managed
- Config changes trigger remove + re-add
1. **TestBgpConfigChanged**
- Tests all BGP configuration change scenarios
- Validates detection of AS, peer, MD5, community changes
- Includes nil multi-hop pointer checks
2. **TestEqualStringSlices**
- Tests slice comparison helper
- Validates empty, identical, and different slices
3. **TestReload** (Integration, requires root)
- Full reload cycle with BGP AS change
- App removal verification
- BGP controller replacement validation
4. **TestReloadAddApp** (Integration)
- Tests adding new app via reload
- Validates app registration
5. **TestReloadMD5Change** (Integration)
- Tests MD5 password change detection
- Validates BGP controller restart
**Decision:** Reload BGP configuration requires full controller restart.
**Rationale:**
- GoBGP library doesn't support modifying peers dynamically
- Simplifies implementation
- Ensures clean state
- Brief interruption is acceptable for infrequent config changes
**Alternative Considered:** Per-peer updates
- Complex to implement correctly
- Partial state issues
- Not supported well by GoBGP library
**Decision:** Log errors but don't crash; maintain old state on failure.
**Rationale:**
- Availability over correctness for config errors
- Admin can fix config and retry
- Better than service downtime
- Logs provide clear error messages
1. **BGP Interruption**
- Full BGP restart causes brief routing interruption
- All routes withdrawn and re-announced
- May impact traffic during reload
2. **No Atomic BGP Updates**
- Cannot add/remove single peer without full restart
- All peers affected even if one changes
3. **No Config Validation**
- Invalid config is detected during reload
- No pre-validation before applying
- Syntax errors require manual fix and retry
4. **No Rollback**
- Failed reload leaves service in potentially inconsistent state
- Manual intervention required to restore
- No automatic rollback to previous config
These changes were written using AI LLM
Authored-By: Claude Code (Sonnet 4.5)
294 lines
6.5 KiB
Go
294 lines
6.5 KiB
Go
package controller
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import (
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"io/ioutil"
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"os"
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"testing"
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"time"
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config "github.com/mayuresh82/gocast/config"
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"github.com/stretchr/testify/assert"
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)
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func TestBgpConfigChanged(t *testing.T) {
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a := assert.New(t)
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mon := &MonitorMgr{}
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// Test 1: No changes
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cfg1 := config.BgpConfig{
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LocalAS: 12345,
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LocalIP: "192.168.1.100",
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Origin: "igp",
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Peers: []config.PeerConfig{
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{PeerIP: "10.10.10.1", PeerAS: 6789},
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},
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Communities: []string{"100:100"},
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}
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cfg2 := cfg1
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a.False(mon.bgpConfigChanged(cfg1, cfg2), "Identical configs should not be considered changed")
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// Test 2: LocalAS changed
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cfg3 := cfg1
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cfg3.LocalAS = 54321
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a.True(mon.bgpConfigChanged(cfg1, cfg3), "LocalAS change should be detected")
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// Test 3: Peer IP changed
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cfg4 := cfg1
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cfg4.Peers = []config.PeerConfig{
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{PeerIP: "10.10.10.2", PeerAS: 6789},
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}
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a.True(mon.bgpConfigChanged(cfg1, cfg4), "Peer IP change should be detected")
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// Test 4: MD5 password changed
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cfg5 := cfg1
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cfg5.Peers = []config.PeerConfig{
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{PeerIP: "10.10.10.1", PeerAS: 6789, MD5Password: "secret"},
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}
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a.True(mon.bgpConfigChanged(cfg1, cfg5), "MD5 password change should be detected")
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// Test 5: Community added
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cfg6 := cfg1
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cfg6.Communities = []string{"100:100", "200:200"}
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a.True(mon.bgpConfigChanged(cfg1, cfg6), "Community addition should be detected")
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// Test 6: Peer added
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cfg7 := cfg1
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cfg7.Peers = []config.PeerConfig{
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{PeerIP: "10.10.10.1", PeerAS: 6789},
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{PeerIP: "10.10.10.2", PeerAS: 6789},
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}
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a.True(mon.bgpConfigChanged(cfg1, cfg7), "Peer addition should be detected")
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// Test 7: MultiHop changed
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multiHopTrue := true
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cfg8 := cfg1
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cfg8.Peers = []config.PeerConfig{
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{PeerIP: "10.10.10.1", PeerAS: 6789, MultiHop: &multiHopTrue},
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}
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a.True(mon.bgpConfigChanged(cfg1, cfg8), "MultiHop change should be detected")
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}
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func TestEqualStringSlices(t *testing.T) {
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a := assert.New(t)
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a.True(equalStringSlices([]string{}, []string{}), "Empty slices should be equal")
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a.True(equalStringSlices([]string{"a", "b"}, []string{"a", "b"}), "Identical slices should be equal")
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a.False(equalStringSlices([]string{"a"}, []string{"a", "b"}), "Different length slices should not be equal")
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a.False(equalStringSlices([]string{"a", "b"}, []string{"a", "c"}), "Different content should not be equal")
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}
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func TestReload(t *testing.T) {
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if os.Getenv("CI") != "" {
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t.Skip("Skipping reload test in CI environment")
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}
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a := assert.New(t)
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// Create initial config file
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initialConfig := `
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agent:
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listen_addr: :8080
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monitor_interval: 10s
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cleanup_timer: 15m
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bgp:
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local_as: 12345
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peer_as: 6789
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local_ip: 192.168.1.100
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origin: igp
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communities:
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- 100:100
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apps:
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- name: test-app
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vip: 1.1.1.1/32
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monitors:
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- exec:echo
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`
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// Create temporary config file
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tmpfile, err := ioutil.TempFile("", "gocast-test-*.yaml")
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a.NoError(err)
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defer os.Remove(tmpfile.Name())
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_, err = tmpfile.Write([]byte(initialConfig))
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a.NoError(err)
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tmpfile.Close()
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// Initialize monitor with initial config
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conf := config.GetConfig(tmpfile.Name())
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mon := NewMonitor(conf)
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defer mon.CloseAll()
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// Wait a bit for initialization
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time.Sleep(100 * time.Millisecond)
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// Verify initial state
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a.Equal(12345, mon.ctrl.localAS)
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m := mon.monitors["test-app"]
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a.NotNil(m, "Initial app should be loaded")
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// Update config file with new BGP AS and remove app
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updatedConfig := `
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agent:
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listen_addr: :8080
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monitor_interval: 10s
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cleanup_timer: 15m
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bgp:
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local_as: 54321
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peer_as: 6789
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local_ip: 192.168.1.100
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origin: igp
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communities:
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- 200:200
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`
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err = ioutil.WriteFile(tmpfile.Name(), []byte(updatedConfig), 0644)
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a.NoError(err)
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// Reload configuration
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err = mon.Reload(tmpfile.Name())
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a.NoError(err)
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// Wait for reload to complete
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time.Sleep(200 * time.Millisecond)
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// Verify new state
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a.Equal(54321, mon.ctrl.localAS)
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a.Equal([]string{"200:200"}, mon.ctrl.communities)
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// Verify app was removed
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mon.monMu.Lock()
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_, exists := mon.monitors["test-app"]
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mon.monMu.Unlock()
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a.False(exists, "App should be removed after reload")
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}
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func TestReloadAddApp(t *testing.T) {
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if os.Getenv("CI") != "" {
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t.Skip("Skipping reload test in CI environment")
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}
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a := assert.New(t)
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// Create initial config without apps
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initialConfig := `
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agent:
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listen_addr: :8080
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monitor_interval: 10s
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bgp:
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local_as: 12345
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peer_as: 6789
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local_ip: 192.168.1.100
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origin: igp
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`
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tmpfile, err := ioutil.TempFile("", "gocast-test-*.yaml")
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a.NoError(err)
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defer os.Remove(tmpfile.Name())
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_, err = tmpfile.Write([]byte(initialConfig))
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a.NoError(err)
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tmpfile.Close()
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conf := config.GetConfig(tmpfile.Name())
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mon := NewMonitor(conf)
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defer mon.CloseAll()
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time.Sleep(100 * time.Millisecond)
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// Verify no apps initially
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mon.monMu.Lock()
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initialCount := len(mon.monitors)
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mon.monMu.Unlock()
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a.Equal(0, initialCount)
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// Add app to config
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updatedConfig := `
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agent:
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listen_addr: :8080
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monitor_interval: 10s
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bgp:
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local_as: 12345
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peer_as: 6789
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local_ip: 192.168.1.100
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origin: igp
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apps:
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- name: new-app
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vip: 2.2.2.2/32
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monitors:
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- exec:echo
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`
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err = ioutil.WriteFile(tmpfile.Name(), []byte(updatedConfig), 0644)
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a.NoError(err)
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// Reload
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err = mon.Reload(tmpfile.Name())
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a.NoError(err)
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time.Sleep(200 * time.Millisecond)
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// Verify app was added
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mon.monMu.Lock()
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_, exists := mon.monitors["new-app"]
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mon.monMu.Unlock()
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a.True(exists, "New app should be added after reload")
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}
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func TestReloadMD5Change(t *testing.T) {
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if os.Getenv("CI") != "" {
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t.Skip("Skipping reload test in CI environment")
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}
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a := assert.New(t)
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// Set environment variable for MD5 password
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os.Setenv("BGP_TEST_PASSWORD", "initial_secret")
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defer os.Unsetenv("BGP_TEST_PASSWORD")
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initialConfig := `
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agent:
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listen_addr: :8080
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bgp:
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local_as: 12345
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local_ip: 192.168.1.100
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peers:
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- peer_ip: 10.10.10.1
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peer_as: 6789
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md5_env_var: BGP_TEST_PASSWORD
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origin: igp
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`
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tmpfile, err := ioutil.TempFile("", "gocast-test-*.yaml")
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a.NoError(err)
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defer os.Remove(tmpfile.Name())
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_, err = tmpfile.Write([]byte(initialConfig))
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a.NoError(err)
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tmpfile.Close()
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conf := config.GetConfig(tmpfile.Name())
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mon := NewMonitor(conf)
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defer mon.CloseAll()
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time.Sleep(100 * time.Millisecond)
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// Update environment variable
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os.Setenv("BGP_TEST_PASSWORD", "updated_secret")
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// Reload (MD5 env var change should trigger BGP reload)
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err = mon.Reload(tmpfile.Name())
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a.NoError(err)
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// Note: We can't easily verify the MD5 password changed without
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// actually establishing BGP sessions, but we can verify reload succeeded
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a.NotNil(mon.ctrl)
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}
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