Build payments-api REST layer (Layer 3), mirroring customers-api

6 routes over Payment, composite key (customernumber + checknumber),
proxying to classic-models-api. openid-connect with RFC 8693 token
exchange to classic-models-api audience, rate-limiting, proxy-cache,
audit-log — same structure as customers-api's REST layer.

Keycloak (local): payments-api-audience client scope + payments-api
resource client added, attached to kong-token-exchange-broker's
default scopes. No dedicated protocol mappers on payments-api
itself, same practice as customers-api/mcp-customers.

No MCP layer — same as customers-api, not needed yet.

kong/rest/audit-log-body-capture-bindings.yaml

@@ -0,0 +1,35 @@
+apiVersion: configuration.konghq.com/v1alpha1
+kind: KongPluginBinding
+metadata:
+  name: ${NAME}-payments-api-audit-capture-request-binding
+  namespace: ${NAMESPACE}
+spec:
+  controlPlaneRef:
+    type: konnectNamespacedRef
+    konnectNamespacedRef:
+      name: ${CONTROL_PLANE_REF_NAME}
+  pluginRef:
+    name: ${NAME}-payments-api-audit-capture-request
+  targets:
+    serviceRef:
+      group: configuration.konghq.com
+      kind: KongService
+      name: ${NAME}-payments-api
+---
+apiVersion: configuration.konghq.com/v1alpha1
+kind: KongPluginBinding
+metadata:
+  name: ${NAME}-payments-api-audit-capture-response-binding
+  namespace: ${NAMESPACE}
+spec:
+  controlPlaneRef:
+    type: konnectNamespacedRef
+    konnectNamespacedRef:
+      name: ${CONTROL_PLANE_REF_NAME}
+  pluginRef:
+    name: ${NAME}-payments-api-audit-capture-response
+  targets:
+    serviceRef:
+      group: configuration.konghq.com
+      kind: KongService
+      name: ${NAME}-payments-api

kong/rest/audit-log-body-capture.yaml

@@ -0,0 +1,27 @@
+# dev only: captures raw request/response bodies into kong.ctx.shared for
+# audit-log.yaml's custom_fields_by_lua to read back in the log phase.
+# Drop this file (and its bindings) to stop body capture without touching
+# audit-log.yaml itself — it degrades gracefully to metadata-only logging.
+apiVersion: configuration.konghq.com/v1
+kind: KongPlugin
+metadata:
+  name: ${NAME}-payments-api-audit-capture-request
+  namespace: ${NAMESPACE}
+plugin: pre-function
+config:
+  access:
+    - "kong.ctx.shared.audit_request_body = kong.request.get_raw_body()"
+---
+apiVersion: configuration.konghq.com/v1
+kind: KongPlugin
+metadata:
+  name: ${NAME}-payments-api-audit-capture-response
+  namespace: ${NAMESPACE}
+plugin: post-function
+config:
+  body_filter:
+    - |
+      local chunk = ngx.arg[1]
+      if chunk then
+        kong.ctx.shared.audit_response_body = (kong.ctx.shared.audit_response_body or "") .. chunk
+      end

kong/rest/audit-log.yaml

@@ -0,0 +1,17 @@
+apiVersion: configuration.konghq.com/v1
+kind: KongPlugin
+metadata:
+  name: ${NAME}-payments-api-audit-log
+  namespace: ${NAMESPACE}
+plugin: http-log
+# dev only: the raw Authorization (JWT) header is captured in clear text,
+# not acceptable as-is for a non-dev environment. request_body/response_body
+# below read from kong.ctx.shared, populated by audit-log-body-capture.yaml
+# — nil (and silently omitted) if that file isn't applied.
+config:
+  http_endpoint: ${AUDIT_LOG_ENDPOINT}
+  method: POST
+  content_type: application/json
+  custom_fields_by_lua:
+    request_body: "return kong.ctx.shared.audit_request_body"
+    response_body: "return kong.ctx.shared.audit_response_body"

kong/rest/kongplugin.yaml

@@ -0,0 +1,30 @@
+apiVersion: configuration.konghq.com/v1
+kind: KongPlugin
+metadata:
+  name: ${NAME}-payments-api-openid-connect
+  namespace: ${NAMESPACE}
+plugin: openid-connect
+config:
+  issuer: ${OIDC_ISSUER}
+  audience_required: ${BACKEND_AUDIENCE}
+  auth_methods:
+    - bearer
+  display_errors: false
+  ssl_verify: true
+  consumer_claims:
+    - - sub
+  consumer_by:
+    - custom_id
+    - username
+  consumer_optional: true
+  client_id:
+    - ${TOKEN_EXCHANGE_CLIENT_ID}
+  client_secret:
+    - ${TOKEN_EXCHANGE_CLIENT_SECRET}
+  token_exchange:
+    subject_token_issuers:
+      - issuer: ${OIDC_ISSUER}
+        conditions: {}
+    request:
+      audience: ${BACKEND_AUDIENCE}
+      scopes: ${BACKEND_SCOPES}

kong/rest/path-rewrite-bindings.yaml

@@ -0,0 +1,107 @@
+apiVersion: configuration.konghq.com/v1alpha1
+kind: KongPluginBinding
+metadata:
+  name: ${NAME}-payments-api-rewrite-listpayments-binding
+  namespace: ${NAMESPACE}
+spec:
+  controlPlaneRef:
+    type: konnectNamespacedRef
+    konnectNamespacedRef:
+      name: ${CONTROL_PLANE_REF_NAME}
+  pluginRef:
+    name: ${NAME}-payments-api-rewrite-listpayments
+  targets:
+    routeRef:
+      group: configuration.konghq.com
+      kind: KongRoute
+      name: ${NAME}-payments-api-listpayments
+---
+apiVersion: configuration.konghq.com/v1alpha1
+kind: KongPluginBinding
+metadata:
+  name: ${NAME}-payments-api-rewrite-createpayment-binding
+  namespace: ${NAMESPACE}
+spec:
+  controlPlaneRef:
+    type: konnectNamespacedRef
+    konnectNamespacedRef:
+      name: ${CONTROL_PLANE_REF_NAME}
+  pluginRef:
+    name: ${NAME}-payments-api-rewrite-createpayment
+  targets:
+    routeRef:
+      group: configuration.konghq.com
+      kind: KongRoute
+      name: ${NAME}-payments-api-createpayment
+---
+apiVersion: configuration.konghq.com/v1alpha1
+kind: KongPluginBinding
+metadata:
+  name: ${NAME}-payments-api-rewrite-getpayment-binding
+  namespace: ${NAMESPACE}
+spec:
+  controlPlaneRef:
+    type: konnectNamespacedRef
+    konnectNamespacedRef:
+      name: ${CONTROL_PLANE_REF_NAME}
+  pluginRef:
+    name: ${NAME}-payments-api-rewrite-getpayment
+  targets:
+    routeRef:
+      group: configuration.konghq.com
+      kind: KongRoute
+      name: ${NAME}-payments-api-getpayment
+---
+apiVersion: configuration.konghq.com/v1alpha1
+kind: KongPluginBinding
+metadata:
+  name: ${NAME}-payments-api-rewrite-updatepayment-binding
+  namespace: ${NAMESPACE}
+spec:
+  controlPlaneRef:
+    type: konnectNamespacedRef
+    konnectNamespacedRef:
+      name: ${CONTROL_PLANE_REF_NAME}
+  pluginRef:
+    name: ${NAME}-payments-api-rewrite-updatepayment
+  targets:
+    routeRef:
+      group: configuration.konghq.com
+      kind: KongRoute
+      name: ${NAME}-payments-api-updatepayment
+---
+apiVersion: configuration.konghq.com/v1alpha1
+kind: KongPluginBinding
+metadata:
+  name: ${NAME}-payments-api-rewrite-patchpayment-binding
+  namespace: ${NAMESPACE}
+spec:
+  controlPlaneRef:
+    type: konnectNamespacedRef
+    konnectNamespacedRef:
+      name: ${CONTROL_PLANE_REF_NAME}
+  pluginRef:
+    name: ${NAME}-payments-api-rewrite-patchpayment
+  targets:
+    routeRef:
+      group: configuration.konghq.com
+      kind: KongRoute
+      name: ${NAME}-payments-api-patchpayment
+---
+apiVersion: configuration.konghq.com/v1alpha1
+kind: KongPluginBinding
+metadata:
+  name: ${NAME}-payments-api-rewrite-deletepayment-binding
+  namespace: ${NAMESPACE}
+spec:
+  controlPlaneRef:
+    type: konnectNamespacedRef
+    konnectNamespacedRef:
+      name: ${CONTROL_PLANE_REF_NAME}
+  pluginRef:
+    name: ${NAME}-payments-api-rewrite-deletepayment
+  targets:
+    routeRef:
+      group: configuration.konghq.com
+      kind: KongRoute
+      name: ${NAME}-payments-api-deletepayment

kong/rest/path-rewrite.yaml

@@ -0,0 +1,59 @@
+apiVersion: configuration.konghq.com/v1
+kind: KongPlugin
+metadata:
+  name: ${NAME}-payments-api-rewrite-listpayments
+  namespace: ${NAMESPACE}
+plugin: request-transformer-advanced
+config:
+  replace:
+    uri: /classic-models/api/v1/payments/
+---
+apiVersion: configuration.konghq.com/v1
+kind: KongPlugin
+metadata:
+  name: ${NAME}-payments-api-rewrite-createpayment
+  namespace: ${NAMESPACE}
+plugin: request-transformer-advanced
+config:
+  replace:
+    uri: /classic-models/api/v1/payments/
+---
+apiVersion: configuration.konghq.com/v1
+kind: KongPlugin
+metadata:
+  name: ${NAME}-payments-api-rewrite-getpayment
+  namespace: ${NAMESPACE}
+plugin: request-transformer-advanced
+config:
+  replace:
+    uri: /classic-models/api/v1/payments/$(uri_captures.customernumber)/$(uri_captures.checknumber)/
+---
+apiVersion: configuration.konghq.com/v1
+kind: KongPlugin
+metadata:
+  name: ${NAME}-payments-api-rewrite-updatepayment
+  namespace: ${NAMESPACE}
+plugin: request-transformer-advanced
+config:
+  replace:
+    uri: /classic-models/api/v1/payments/$(uri_captures.customernumber)/$(uri_captures.checknumber)/
+---
+apiVersion: configuration.konghq.com/v1
+kind: KongPlugin
+metadata:
+  name: ${NAME}-payments-api-rewrite-patchpayment
+  namespace: ${NAMESPACE}
+plugin: request-transformer-advanced
+config:
+  replace:
+    uri: /classic-models/api/v1/payments/$(uri_captures.customernumber)/$(uri_captures.checknumber)/
+---
+apiVersion: configuration.konghq.com/v1
+kind: KongPlugin
+metadata:
+  name: ${NAME}-payments-api-rewrite-deletepayment
+  namespace: ${NAMESPACE}
+plugin: request-transformer-advanced
+config:
+  replace:
+    uri: /classic-models/api/v1/payments/$(uri_captures.customernumber)/$(uri_captures.checknumber)/

kong/rest/pluginbindings.yaml

@@ -0,0 +1,71 @@
+apiVersion: configuration.konghq.com/v1alpha1
+kind: KongPluginBinding
+metadata:
+  name: ${NAME}-payments-api-openid-connect-binding
+  namespace: ${NAMESPACE}
+spec:
+  controlPlaneRef:
+    type: konnectNamespacedRef
+    konnectNamespacedRef:
+      name: ${CONTROL_PLANE_REF_NAME}
+  pluginRef:
+    name: ${NAME}-payments-api-openid-connect
+  targets:
+    serviceRef:
+      group: configuration.konghq.com
+      kind: KongService
+      name: ${NAME}-payments-api
+---
+apiVersion: configuration.konghq.com/v1alpha1
+kind: KongPluginBinding
+metadata:
+  name: ${NAME}-payments-api-rate-limiting-binding
+  namespace: ${NAMESPACE}
+spec:
+  controlPlaneRef:
+    type: konnectNamespacedRef
+    konnectNamespacedRef:
+      name: ${CONTROL_PLANE_REF_NAME}
+  pluginRef:
+    name: ${NAME}-payments-api-rate-limiting
+  targets:
+    serviceRef:
+      group: configuration.konghq.com
+      kind: KongService
+      name: ${NAME}-payments-api
+---
+apiVersion: configuration.konghq.com/v1alpha1
+kind: KongPluginBinding
+metadata:
+  name: ${NAME}-payments-api-proxy-cache-binding
+  namespace: ${NAMESPACE}
+spec:
+  controlPlaneRef:
+    type: konnectNamespacedRef
+    konnectNamespacedRef:
+      name: ${CONTROL_PLANE_REF_NAME}
+  pluginRef:
+    name: ${NAME}-payments-api-proxy-cache
+  targets:
+    serviceRef:
+      group: configuration.konghq.com
+      kind: KongService
+      name: ${NAME}-payments-api
+---
+apiVersion: configuration.konghq.com/v1alpha1
+kind: KongPluginBinding
+metadata:
+  name: ${NAME}-payments-api-audit-log-binding
+  namespace: ${NAMESPACE}
+spec:
+  controlPlaneRef:
+    type: konnectNamespacedRef
+    konnectNamespacedRef:
+      name: ${CONTROL_PLANE_REF_NAME}
+  pluginRef:
+    name: ${NAME}-payments-api-audit-log
+  targets:
+    serviceRef:
+      group: configuration.konghq.com
+      kind: KongService
+      name: ${NAME}-payments-api

kong/rest/proxy-cache.yaml

@@ -0,0 +1,16 @@
+apiVersion: configuration.konghq.com/v1
+kind: KongPlugin
+metadata:
+  name: ${NAME}-payments-api-proxy-cache
+  namespace: ${NAMESPACE}
+plugin: proxy-cache-advanced
+config:
+  strategy: memory
+  request_method:
+    - GET
+    - HEAD
+  response_code:
+    - 200
+  content_type:
+    - application/json
+  cache_ttl: 60

kong/rest/rate-limiting.yaml

@@ -0,0 +1,14 @@
+apiVersion: configuration.konghq.com/v1
+kind: KongPlugin
+metadata:
+  name: ${NAME}-payments-api-rate-limiting
+  namespace: ${NAMESPACE}
+plugin: rate-limiting-advanced
+config:
+  limit:
+    - ${API_RATE_LIMIT_MINUTE}
+  window_size:
+    - 60
+  identifier: consumer
+  sync_rate: -1
+  strategy: local

kong/rest/routes.yaml

@@ -0,0 +1,119 @@
+apiVersion: configuration.konghq.com/v1alpha1
+kind: KongRoute
+metadata:
+  name: ${NAME}-payments-api-listpayments
+  namespace: ${NAMESPACE}
+spec:
+  serviceRef:
+    type: namespacedRef
+    namespacedRef:
+      name: ${NAME}-payments-api
+  name: payments-api_listpayments
+  methods:
+    - GET
+    - OPTIONS
+  paths:
+    - /payments/v1/payments/
+  strip_path: false
+  tags:
+    - payments
+---
+apiVersion: configuration.konghq.com/v1alpha1
+kind: KongRoute
+metadata:
+  name: ${NAME}-payments-api-createpayment
+  namespace: ${NAMESPACE}
+spec:
+  serviceRef:
+    type: namespacedRef
+    namespacedRef:
+      name: ${NAME}-payments-api
+  name: payments-api_createpayment
+  methods:
+    - POST
+    - OPTIONS
+  paths:
+    - /payments/v1/payments/
+  strip_path: false
+  tags:
+    - payments
+---
+apiVersion: configuration.konghq.com/v1alpha1
+kind: KongRoute
+metadata:
+  name: ${NAME}-payments-api-getpayment
+  namespace: ${NAMESPACE}
+spec:
+  serviceRef:
+    type: namespacedRef
+    namespacedRef:
+      name: ${NAME}-payments-api
+  name: payments-api_getpayment
+  methods:
+    - GET
+    - OPTIONS
+  paths:
+    - ~/payments/v1/payments/(?<customernumber>[^#?/]+)/(?<checknumber>[^#?/]+)/$
+  strip_path: false
+  tags:
+    - payments
+---
+apiVersion: configuration.konghq.com/v1alpha1
+kind: KongRoute
+metadata:
+  name: ${NAME}-payments-api-updatepayment
+  namespace: ${NAMESPACE}
+spec:
+  serviceRef:
+    type: namespacedRef
+    namespacedRef:
+      name: ${NAME}-payments-api
+  name: payments-api_updatepayment
+  methods:
+    - PUT
+    - OPTIONS
+  paths:
+    - ~/payments/v1/payments/(?<customernumber>[^#?/]+)/(?<checknumber>[^#?/]+)/$
+  strip_path: false
+  tags:
+    - payments
+---
+apiVersion: configuration.konghq.com/v1alpha1
+kind: KongRoute
+metadata:
+  name: ${NAME}-payments-api-patchpayment
+  namespace: ${NAMESPACE}
+spec:
+  serviceRef:
+    type: namespacedRef
+    namespacedRef:
+      name: ${NAME}-payments-api
+  name: payments-api_patchpayment
+  methods:
+    - PATCH
+    - OPTIONS
+  paths:
+    - ~/payments/v1/payments/(?<customernumber>[^#?/]+)/(?<checknumber>[^#?/]+)/$
+  strip_path: false
+  tags:
+    - payments
+---
+apiVersion: configuration.konghq.com/v1alpha1
+kind: KongRoute
+metadata:
+  name: ${NAME}-payments-api-deletepayment
+  namespace: ${NAMESPACE}
+spec:
+  serviceRef:
+    type: namespacedRef
+    namespacedRef:
+      name: ${NAME}-payments-api
+  name: payments-api_deletepayment
+  methods:
+    - DELETE
+    - OPTIONS
+  paths:
+    - ~/payments/v1/payments/(?<customernumber>[^#?/]+)/(?<checknumber>[^#?/]+)/$
+  strip_path: false
+  tags:
+    - payments

kong/rest/service.yaml

@@ -0,0 +1,17 @@
+apiVersion: configuration.konghq.com/v1alpha1
+kind: KongService
+metadata:
+  name: ${NAME}-payments-api
+  namespace: ${NAMESPACE}
+spec:
+  controlPlaneRef:
+    type: konnectNamespacedRef
+    konnectNamespacedRef:
+      name: ${CONTROL_PLANE_REF_NAME}
+  name: payments-api
+  host: ${BACKEND_HOST}
+  port: 8000
+  protocol: http
+  path: /
+  tags:
+    - payments