tests: Add tests for health checker

Author: jordigh

test/server/lib/HealthChecker.ts

@@ -0,0 +1,137 @@
+import {TestServer} from 'test/server/lib/helpers/TestServer';
+import {RedisForwarder} from 'test/server/tcpForwarder';
+import * as testUtils from 'test/server/testUtils';
+import {prepareFilesystemDirectoryForTests} from 'test/server/lib/helpers/PrepareFilesystemDirectoryForTests';
+import {prepareDatabase} from 'test/server/lib/helpers/PrepareDatabase';
+
+import fetch from 'node-fetch';
+import {assert} from 'chai';
+import IORedis from "ioredis";
+
+import * as path from 'path';
+import {tmpdir} from 'os';
+
+const username = process.env.USER || "nobody";
+const tmpDir = path.join(tmpdir(), `grist_test_${username}_health_checker`);
+
+describe('HealthChecker', function() {
+  testUtils.setTmpLogLevel('error');
+  this.timeout(10_000);
+
+  let servers: {server: TestServer, forwarder?: RedisForwarder}[] = [];
+  let client: IORedis;
+
+  before(async function() {
+    await prepareFilesystemDirectoryForTests(tmpDir);
+    await prepareDatabase(tmpDir);
+
+    if(process.env.TEST_REDIS_URL) {
+      client = new IORedis(process.env.TEST_REDIS_URL);
+      await client.flushall();
+
+      for(let i = 0; i < 3; i++) {
+        // Use a forwarder for each server so we can simulate
+        // disconnects
+        const forwarder = await RedisForwarder.create();
+
+        const server = await TestServer.startServer('home', tmpDir, `with-redis-${i}`, {
+          REDIS_URL: forwarder.redisUrl,
+          GRIST_INSTANCE_ID: `test-instance-${i}`,
+        });
+        servers.push({server, forwarder});
+      }
+    }
+    else {
+      servers = [{server: await TestServer.startServer('home', tmpDir, 'without-redis')}];
+    }
+  });
+
+  after(async function () {
+    await Promise.all(servers.map(async (pair) => {
+      await pair.server.stop();
+      await pair.forwarder?.disconnect();
+    }));
+    client?.disconnect();
+  });
+
+  it('registers all servers', async function () {
+    if(!process.env.TEST_REDIS_URL) {
+      this.skip();
+    }
+
+    const instances = await client.smembers('grist-instances');
+    instances.sort();
+    assert.deepEqual(instances, ['test-instance-0', 'test-instance-1', 'test-instance-2']);
+  });
+
+  it('reports healthy when all servers are healthy', async function () {
+    const server = servers[process.env.TEST_REDIS_URL ? 2 : 0].server;
+    const resp = await fetch(`${server.serverUrl}/status?allInstancesReady=1`);
+    assert.equal(resp.status, 200);
+    assert.match(await resp.text(), /allInstancesReady ok/);
+  });
+
+  it('reports not healthy when one server is not healthy', async function () {
+    if(!process.env.TEST_REDIS_URL) {
+      this.skip();
+    }
+
+    const downServer = servers[2];
+    await downServer.forwarder?.disconnect();
+
+    const server = servers[0].server;
+    const resp = await fetch(`${server.serverUrl}/status?allInstancesReady=1&timeout=500`);
+    const text = await resp.text();
+    assert.equal(resp.status, 500);
+    assert.match(text, /allInstancesReady not ok/);
+
+    await downServer.forwarder?.connect();
+  });
+
+  it('reports healthy when one server is cleanly disconnected', async function () {
+    if(!process.env.TEST_REDIS_URL) {
+      this.skip();
+    }
+
+    const downServer = servers[2];
+    await downServer.server.stop();
+    await downServer.forwarder?.disconnect();
+    servers.pop();
+
+    const server = servers[0].server;
+    const resp = await fetch(`${server.serverUrl}/status?allInstancesReady=1`);
+    const text = await resp.text();
+    assert.equal(resp.status, 200);
+    assert.match(text, /allInstancesReady ok/);
+  });
+
+  it('checks when a new server comes back', async function() {
+    if(!process.env.TEST_REDIS_URL) {
+      this.skip();
+    }
+
+    let instances = await client.smembers('grist-instances');
+    instances.sort();
+    assert.deepEqual(instances, ['test-instance-0', 'test-instance-1']);
+
+    const newForwarder = await RedisForwarder.create();
+    await newForwarder.connect();
+    const newServer = await TestServer.startServer('home', tmpDir, `with-redis-3`, {
+      REDIS_URL: newForwarder.redisUrl,
+      GRIST_INSTANCE_ID: `test-instance-3`,
+    });
+
+    instances = await client.smembers('grist-instances');
+    instances.sort();
+    assert.deepEqual(instances, ['test-instance-0', 'test-instance-1', 'test-instance-3']);
+
+    const server = servers[0].server;
+    const resp = await fetch(`${server.serverUrl}/status?allInstancesReady=1`);
+    const text = await resp.text();
+    assert.equal(resp.status, 200);
+    assert.match(text, /allInstancesReady ok/);
+
+    await newServer.stop();
+    await newForwarder.disconnect();
+  });
+});