Add an API endpoint to get backend storage layout version for a given zone.

Signed-off-by: Miod Vallat <[email protected]>

Author: miodvallat

.github/actions/spell-check/expect.txt

@@ -1339,6 +1339,7 @@ stickysidebar
 Stillaway
 Stirnimann
 Stolte
+storageversion
 Storbeck
 Storesund
 stou

docs/http-api/swagger/authoritative-api-swagger.yaml

@@ -1,6 +1,6 @@
 swagger: '2.0'
 info:
-  version: "0.0.17"
+  version: "0.0.18"
   title: PowerDNS Authoritative HTTP API
   license:
     name: MIT
@@ -79,6 +79,30 @@ paths:
             $ref: '#/definitions/Server'
         <<: *commonErrors
 
+  '/servers/{server_id}/backends/{backend_id}/storageversion':
+    get:
+      summary: 'Return the backend storage version used to store zone data.'
+      description: 'This returns a backend-dependent version information. Currently only supported by the LMDB backend.'
+      tags:
+        - zones
+      parameters:
+        - name: server_id
+          in: path
+          required: true
+          description: The id of the server to retrieve
+          type: string
+        - name: backend_id
+          type: string
+          in: path
+          required: true
+          description: The name of the backend to query
+      responses:
+        '200':
+          description: Storage version number
+          schema:
+              $ref: '#/definitions/StorageVersion'
+        <<: *commonErrors
+
   '/servers/{server_id}/cache/flush':
     put:
       summary: Flush a cache-entry by name
@@ -1611,3 +1635,10 @@ definitions:
         items:
           $ref: '#/definitions/Network'
 
+  StorageVersion:
+    title: StorageVersion
+    description: 'The version number of the backend storage for a zone'
+    properties:
+      storageversion:
+        type: number
+

pdns/ws-auth.cc

@@ -1926,6 +1926,30 @@ static void apiServerAutoprimariesPOST(HttpRequest* req, HttpResponse* resp)
   resp->status = 201;
 }
 
+static void apiServerBackendStorageVersion(HttpRequest* req, HttpResponse* resp)
+{
+  const std::string backendName = req->parameters["id"];
+  UeberBackend backend;
+  for (auto& onebackend : backend.backends) {
+    if (onebackend->getPrefix() == backendName) {
+      auto version = onebackend->getStorageLayoutVersion();
+      if (version < 0) {
+        throw ApiException("Storage layout version not available");
+      }
+
+      if (req->accept_json) {
+        resp->setJsonBody(Json::object{{"storageversion", version}});
+      }
+      else {
+        resp->headers["Content-Type"] = "text/plain; charset=us-ascii";
+        resp->body = std::to_string(version);
+      }
+      return;
+    }
+  }
+  throw ApiException("Unknown backend");
+}
+
 // create new zone
 static void apiServerZonesPOST(HttpRequest* req, HttpResponse* resp)
 {
@@ -3020,6 +3044,7 @@ void AuthWebServer::webThread()
       d_ws->registerApiHandler("/api/v1/servers/localhost/autoprimaries/<ip>/<nameserver>", &apiServerAutoprimaryDetailDELETE, "DELETE");
       d_ws->registerApiHandler("/api/v1/servers/localhost/autoprimaries", &apiServerAutoprimariesGET, "GET");
       d_ws->registerApiHandler("/api/v1/servers/localhost/autoprimaries", &apiServerAutoprimariesPOST, "POST");
+      d_ws->registerApiHandler("/api/v1/servers/localhost/backends/<id>/storageversion", apiServerBackendStorageVersion, "GET");
       d_ws->registerApiHandler("/api/v1/servers/localhost/networks", apiServerNetworksGET, "GET");
       d_ws->registerApiHandler("/api/v1/servers/localhost/networks/<ip>/<prefixlen>", apiServerNetworksGET, "GET");
       d_ws->registerApiHandler("/api/v1/servers/localhost/networks/<ip>/<prefixlen>", apiServerNetworksPUT, "PUT");

regression-tests.api/test_Backends.py

@@ -0,0 +1,20 @@
+from __future__ import print_function
+import json
+import operator
+import unittest
+import requests.exceptions
+from test_helper import ApiTestCase, is_auth, is_auth_lmdb, BACKEND
+
+@unittest.skipIf(not is_auth(), "Not applicable")
+class AuthBackends(ApiTestCase):
+
+    def test_storage_version(self):
+        # Require a json answer to GET
+        self.session.headers['Content-Type'] = 'application/json'
+        r = self.session.get(self.url("/api/v1/servers/localhost/backends/" + BACKEND + "/storageversion"))
+        if is_auth_lmdb():
+            self.assertEqual(r.status_code, 200)
+            self.assertGreater(r.json()['storageversion'], 5)
+        else:
+            self.assertEqual(r.status_code, 422)
+