feat: enhance BGP template and peer configuration handling. Introduce policies_json parameter for local IP and ASN overrides in BGP speakers. Implement BGP template rendering and update peer configuration to utilize templates, improving flexibility in BGP setup. Add tests for new rendering logic and ensure proper integration with existing configurations.

internal/pipeline/refresh.go

@@ -236,6 +236,16 @@ func buildPreviewFragments(st store.Backend, tenantID, moduleID, revisionID stri
 	staticV6 := birdfmt.RenderStaticIPv6Routes("evobgp_prefixes_v6", sr6)
 
 	locals := birdLocalsFromStore(st, tenantID)
+	tplBody, err := birdfmt.RenderBGPTemplates(birdfmt.BGPTemplatesOptions{
+		LocalIPv4:      locals.localV4,
+		LocalIPv6:      locals.localV6,
+		LocalASN:       locals.localASN,
+		ExportFilterV4: birdFilterNameV4,
+		ExportFilterV6: birdFilterNameV6,
+	})
+	if err != nil {
+		return nil, err
+	}
 	peersBody, err := renderPeersBirdFragment(st, tenantID, locals)
 	if err != nil {
 		return nil, err
@@ -252,6 +262,7 @@ func buildPreviewFragments(st store.Backend, tenantID, moduleID, revisionID stri
 
 	p4 := birdfmt.FragmentIncludePath(birdfmt.FragmentFiltersV4)
 	p6 := birdfmt.FragmentIncludePath(birdfmt.FragmentFiltersV6)
+	pTpl := birdfmt.FragmentIncludePath(birdfmt.FragmentBGPTemplate)
 	px4 := birdfmt.FragmentIncludePath(birdfmt.FragmentPrefixesV4)
 	px6 := birdfmt.FragmentIncludePath(birdfmt.FragmentPrefixesV6)
 	pPeers := birdfmt.FragmentIncludePath(birdfmt.FragmentPeers)
@@ -260,6 +271,7 @@ func buildPreviewFragments(st store.Backend, tenantID, moduleID, revisionID stri
 		"bird.conf": main,
 		p4:          birdfmt.JoinFragments(birdfmt.ManagedBanner(revisionID), f4),
 		p6:          birdfmt.JoinFragments(birdfmt.ManagedBanner(revisionID), f6),
+		pTpl:        birdfmt.JoinFragments(birdfmt.ManagedBanner(revisionID), tplBody),
 		px4:         birdfmt.JoinFragments(birdfmt.ManagedBanner(revisionID), staticV4),
 		px6:         birdfmt.JoinFragments(birdfmt.ManagedBanner(revisionID), staticV6),
 		pPeers:      peersBody,
@@ -346,6 +358,30 @@ type peerPolicyJSON struct {
 	LocalASN  float64 `json:"local_asn"`
 }
 
+func effectivePeerLocals(loc birdLocals, pol peerPolicyJSON) (v4, v6 string, asn uint32) {
+	v4 = strings.TrimSpace(loc.localV4)
+	v6 = strings.TrimSpace(loc.localV6)
+	if s := strings.TrimSpace(pol.LocalIPv4); s != "" {
+		v4 = s
+	}
+	if s := strings.TrimSpace(pol.LocalIPv6); s != "" {
+		v6 = s
+	}
+	asn = loc.localASN
+	if pol.LocalASN >= 1 && pol.LocalASN <= 4294967295 {
+		asn = uint32(pol.LocalASN)
+	}
+	return v4, v6, asn
+}
+
+// peerNeedsLocalOverride is true when the peer's effective local IP or ASN differs from tenant defaults in the BGP template.
+func peerNeedsLocalOverride(loc birdLocals, effLocal string, effASN uint32, ipv4 bool) bool {
+	if ipv4 {
+		return strings.TrimSpace(effLocal) != strings.TrimSpace(loc.localV4) || effASN != loc.localASN
+	}
+	return strings.TrimSpace(effLocal) != strings.TrimSpace(loc.localV6) || effASN != loc.localASN
+}
+
 func renderPeersBirdFragment(st store.Backend, tenantID string, loc birdLocals) (string, error) {
 	peers := st.ListPeers(tenantID)
 	var parts []string
@@ -362,29 +398,22 @@ func renderPeersBirdFragment(st store.Backend, tenantID string, loc birdLocals)
 			continue
 		}
 		pol := parsePeerPolicies(p.PoliciesJSON)
-		lv4 := loc.localV4
-		if strings.TrimSpace(pol.LocalIPv4) != "" {
-			lv4 = strings.TrimSpace(pol.LocalIPv4)
-		}
-		lv6 := loc.localV6
-		if strings.TrimSpace(pol.LocalIPv6) != "" {
-			lv6 = strings.TrimSpace(pol.LocalIPv6)
-		}
-		asn := loc.localASN
-		if pol.LocalASN >= 1 && pol.LocalASN <= 4294967295 {
-			asn = uint32(pol.LocalASN)
-		}
+		lv4, lv6, asn := effectivePeerLocals(loc, pol)
 		proto := peerProtocolName(p.ID)
 		ra := uint32(p.RemoteASN)
 		if addr.Is4() {
-			s, err := birdfmt.RenderProtocolBGPIPv4(birdfmt.BGPPeerIPv4Options{
-				ProtocolName: proto,
-				LocalIP:      lv4,
-				LocalASN:     asn,
-				NeighborIP:   addr.String(),
-				NeighborASN:  ra,
-				ExportFilter: birdFilterNameV4,
-			})
+			opts := birdfmt.BGPPeerFromTemplateOptions{
+				ProtocolName:  proto,
+				TemplateName:  birdfmt.BGPTemplateNameV4,
+				NeighborIP:    addr.String(),
+				NeighborASN:   ra,
+				SourceAddress: lv4,
+			}
+			if peerNeedsLocalOverride(loc, lv4, asn, true) {
+				opts.OverrideLocalIP = lv4
+				opts.OverrideLocalASN = asn
+			}
+			s, err := birdfmt.RenderProtocolBGPFromTemplate(opts)
 			if err != nil {
 				return "", err
 			}
@@ -392,14 +421,18 @@ func renderPeersBirdFragment(st store.Backend, tenantID string, loc birdLocals)
 			continue
 		}
 		if addr.Is6() {
-			s, err := birdfmt.RenderProtocolBGPIPv6(birdfmt.BGPPeerIPv6Options{
-				ProtocolName: proto,
-				LocalIP:      lv6,
-				LocalASN:     asn,
-				NeighborIP:   addr.String(),
-				NeighborASN:  ra,
-				ExportFilter: birdFilterNameV6,
-			})
+			opts := birdfmt.BGPPeerFromTemplateOptions{
+				ProtocolName:  proto,
+				TemplateName:  birdfmt.BGPTemplateNameV6,
+				NeighborIP:    addr.String(),
+				NeighborASN:   ra,
+				SourceAddress: lv6,
+			}
+			if peerNeedsLocalOverride(loc, lv6, asn, false) {
+				opts.OverrideLocalIP = lv6
+				opts.OverrideLocalASN = asn
+			}
+			s, err := birdfmt.RenderProtocolBGPFromTemplate(opts)
 			if err != nil {
 				return "", err
 			}