CLDSRV-574 implement KMS health check

lib/kms/Cache.js

@@ -0,0 +1,65 @@
+class Cache {
+    constructor() {
+        this.lastChecked = null;
+        this.result = null;
+    }
+
+    /**
+     * Retrieves the cached result with the last checked timestamp.
+     * @returns {object|null} An object containing the result and lastChecked, or null if not set.
+     */
+    getResult() {
+        if (!this.result) {
+            return null;
+        }
+
+        return Object.assign({}, this.result, {
+            lastChecked: this.lastChecked ? new Date(this.lastChecked).toISOString() : null,
+        });
+    }
+
+    /**
+     * Retrieves the last checked timestamp.
+     * @returns {number|null} The timestamp of the last check or null if never checked.
+     */
+    getLastChecked() {
+        return this.lastChecked;
+    }
+
+    /**
+     * Updates the cache with a new result and timestamp.
+     * @param {object} result - The result to cache.
+     * @returns {undefined}
+     */
+    setResult(result) {
+        this.lastChecked = Date.now();
+        this.result = result;
+    }
+
+    /**
+     * Determines if the cache should be refreshed based on the last checked time.
+     * @param {number} duration - Duration in milliseconds for cache validity.
+     * @returns {boolean} true if the cache should be refreshed, else false.
+     */
+    shouldRefresh(duration = 1 * 60 * 60 * 1000) { // Default: 1 hour
+        if (!this.lastChecked) {
+            return true;
+        }
+
+        const now = Date.now();
+        const elapsed = now - this.lastChecked;
+        const jitter = Math.floor(Math.random() * 15 * 60 * 1000); // Up to 15 minutes
+        return elapsed > (duration - jitter);
+    }
+
+    /**
+     * Clears the cache.
+     * @returns {undefined}
+     */
+    clear() {
+        this.lastChecked = null;
+        this.result = null;
+    }
+}
+
+module.exports = Cache;

lib/kms/wrapper.js

@@ -8,6 +8,8 @@ const inMemory = require('./in_memory/backend').backend;
 const file = require('./file/backend');
 const KMIPClient = require('arsenal').network.kmipClient;
 const Common = require('./common');
+const Cache = require('./Cache');
+const cache = new Cache();
 let scalityKMS;
 let scalityKMSImpl;
 try {
@@ -306,21 +308,47 @@ class KMS {
                 [implName]: { code: 200, message: 'OK' },
             });
         }
-        return client.healthcheck(log, err => {
-            const respBody = {};
-            if (err) {
-                respBody[implName] = {
-                    error: err.description,
-                    code: err.code,
-                };
-            } else {
-                respBody[implName] = {
-                    code: 200,
-                    message: 'OK',
-                };
-            }
-            return cb(null, respBody);
-        });
+
+        const cachedResult = cache.getResult();
+        logger.debug('current KMS cache state', { result: cachedResult });
+
+        const shouldRefreshCache = cache.shouldRefresh();
+
+        if (shouldRefreshCache) {
+            logger.debug('health check for KMS backend');
+            return client.healthcheck(log, err => {
+                let res;
+                if (err) {
+                    res = {
+                        // The following response makes sure that if KMS is down,
+                        // cloudserver health check is still healthy.
+                        // Simply including an error code in the response won't cause the health check to fail.
+                        // Instead, the healthCheck logic detects errors by checking for the "error" field.
+                        code: err.code,
+                        message: 'KMS health check failed',
+                        description: err.description,
+                    };
+                    logger.warn('KMS health check failed', { errorCode: err.code, error: err.description });
+                } else {
+                    res = {
+                        code: 200,
+                        message: 'OK',
+                    };
+                    logger.info('KMS health check succeeded', { res });
+                }
+
+                cache.setResult(res);
+                const updatedResult = cache.getResult();
+                logger.debug('updated KMS cache:', { result: updatedResult });
+
+                const respBody = { [implName]: updatedResult };
+                return cb(null, respBody);
+            });
+        }
+
+        // Use cached healthcheck result if within a 1-hour window
+        logger.debug('using cached KMS health check', { cachedResult });
+        return cb(null, { [implName]: cachedResult });
     }
 }
 

lib/utilities/healthcheckHandler.js

@@ -4,6 +4,7 @@ const { data } = require('../data/wrapper');
 const vault = require('../auth/vault');
 const metadata = require('../metadata/wrapper');
 const async = require('async');
+const kms = require('../kms/wrapper');
 
 // current function utility is minimal, but will be expanded
 function isHealthy() {
@@ -40,15 +41,11 @@ function writeResponse(res, error, log, results, cb) {
  * @return {undefined}
  */
 function clientCheck(flightCheckOnStartUp, log, cb) {
-    // FIXME S3C-4833 KMS healthchecks have been disabled:
-    // - they should be reworked to avoid blocking all requests,
-    //   including unencrypted requests
-    // - they should not prevent Cloudserver from starting up
     const clients = [
         data,
         metadata,
         vault,
-        // kms,
+        kms,
     ];
     const clientTasks = [];
     clients.forEach(client => {

tests/unit/encryption/checkHealth.js

@@ -0,0 +1,132 @@
+const assert = require('assert');
+const sinon = require('sinon');
+const { errors } = require('arsenal');
+
+const Cache = require('../../../lib/kms/Cache');
+const { DummyRequestLogger } = require('../helpers');
+const memBackend = require('../../../lib/kms/in_memory/backend');
+const kms = require('../../../lib/kms/wrapper');
+
+const log = new DummyRequestLogger();
+
+describe('KMS.checkHealth', () => {
+    let setResultSpy;
+    let shouldRefreshStub;
+    let clock;
+
+    beforeEach(() => {
+        clock = sinon.useFakeTimers({
+            now: 1625077800000,
+            toFake: ['Date'],
+        });
+
+        setResultSpy = sinon.spy(Cache.prototype, 'setResult');
+        shouldRefreshStub = sinon.stub(Cache.prototype, 'shouldRefresh').returns(true);
+
+        delete memBackend.backend.healthcheck;
+    });
+
+    afterEach(() => {
+        sinon.restore();
+        if (clock) {
+            clock.restore();
+        }
+    });
+
+    it('should return OK when kms backend does not have healthcheck method', done => {
+        kms.checkHealth(log, (err, result) => {
+            assert.ifError(err);
+            assert.deepStrictEqual(result, {
+                memoryKms: { code: 200, message: 'OK' },
+            });
+
+            assert(shouldRefreshStub.notCalled, 'shouldRefresh should not be called');
+            assert(setResultSpy.notCalled, 'setResult should not be called');
+
+            done();
+        });
+    });
+
+    it('should return OK when healthcheck succeeds', done => {
+        memBackend.backend.healthcheck = sinon.stub().callsFake((log, cb) => cb(null));
+
+        kms.checkHealth(log, (err, result) => {
+            assert.ifError(err);
+
+            const expectedLastChecked = new Date(clock.now).toISOString();
+
+            assert.deepStrictEqual(result, {
+                memoryKms: { code: 200, message: 'OK', lastChecked: expectedLastChecked },
+            });
+
+            assert(shouldRefreshStub.calledOnce, 'shouldRefresh should be called once');
+
+            assert(setResultSpy.calledOnceWithExactly({
+                code: 200,
+                message: 'OK',
+            }));
+
+            done();
+        });
+    });
+
+    it('should return failure message when healthcheck fails', done => {
+        memBackend.backend.healthcheck = sinon.stub().callsFake((log, cb) => cb(errors.InternalError));
+
+        kms.checkHealth(log, (err, result) => {
+            assert.ifError(err);
+
+            const expectedLastChecked = new Date(clock.now).toISOString();
+
+            assert.deepStrictEqual(result, {
+                memoryKms: {
+                    code: 500,
+                    message: 'KMS health check failed',
+                    description: 'We encountered an internal error. Please try again.',
+                    lastChecked: expectedLastChecked,
+                },
+            });
+
+            assert(shouldRefreshStub.calledOnce, 'shouldRefresh should be called once');
+
+            assert(setResultSpy.calledOnceWithExactly({
+                code: 500,
+                message: 'KMS health check failed',
+                description: 'We encountered an internal error. Please try again.',
+            }));
+
+            done();
+        });
+    });
+
+    it('should use cached result when not refreshing', done => {
+        memBackend.backend.healthcheck = sinon.stub().callsFake((log, cb) => cb(null));
+        // first call to populate the cache
+        kms.checkHealth(log, err => {
+            assert.ifError(err);
+            shouldRefreshStub.returns(false);
+
+            // second call should use the cached result
+            kms.checkHealth(log, (err, result) => {
+                assert.ifError(err);
+
+                const expectedLastChecked = new Date(clock.now).toISOString();
+                assert.deepStrictEqual(result, {
+                    memoryKms: {
+                        code: 200,
+                        message: 'OK',
+                        lastChecked: expectedLastChecked,
+                    },
+                });
+
+                // once each call
+                assert.strictEqual(shouldRefreshStub.callCount, 2, 'shouldRefresh should be called twice');
+
+                // only the first call
+                assert.strictEqual(setResultSpy.callCount, 1, 'setResult should be called once');
+
+                done();
+            });
+        });
+    });
+});