Adjusted the Request-Id header limit to 7k and updated unit tests

Author: justinwilaby

src/api-client.ts

@@ -174,16 +174,17 @@ export class APIClient {
         delinquencyConfig.warning_shown = true
       }
 
-      // eslint-disable-next-line complexity
       static async request<T>(url: string, opts: APIClient.Options = {}, retries = 3): Promise<APIHTTPClient<T>> {
         opts.headers = opts.headers || {}
         const currentRequestId = RequestId.create() && RequestId.headerValue
 
         // Accumulation of requestIds in the header
-        // causes a header overflow error. These have been
+        // causes a header overflow error. Headers have been
         // observed to be larger than 8k (Node default max)
         // in long running poll operations such as pg:wait
-        if (Buffer.from(currentRequestId).byteLength > 1024 * 8) {
+        // We limit the Request-Id header to 7k to allow some
+        // room fo other headers.
+        if (Buffer.from(currentRequestId).byteLength > 1024 * 7) {
           RequestId.empty()
           opts.headers[requestIdHeader] = RequestId.create()
         } else {

test/api-client.test.ts

@@ -635,5 +635,32 @@ describe('api_client', () => {
 
         expect(secondRequest.getHeader(requestIdHeader)).to.deep.equal('second-random-uuid,first-existing-request-id,second-existing-request-id,random-uuid')
       })
+
+    test
+      .it('resets request id when it exceeds 7KB', async ctx => {
+        const cmd = new Command([], ctx.config)
+        // Create a large request ID that exceeds 7KB
+        const largeRequestId = 'x'.repeat(1024 * 8)
+        Reflect.set(RequestId, 'ids', [largeRequestId])
+
+        generateStub.returns('new-uuid-after-reset')
+        api = nock('https://api.heroku.com').get('/apps').reply(200, [{name: 'myapp'}])
+
+        const {request} = await cmd.heroku.get('/apps')
+        expect(request.getHeader(requestIdHeader)).to.deep.equal(['new-uuid-after-reset'])
+      })
+
+    test
+      .it('keeps existing request id when under 7KB', async ctx => {
+        const cmd = new Command([], ctx.config)
+        // Create a request ID that's under 7KB
+        const normalRequestId = 'normal-request-id'
+        Reflect.set(RequestId, 'ids', [normalRequestId])
+
+        api = nock('https://api.heroku.com').get('/apps').reply(200, [{name: 'myapp'}])
+
+        const {request} = await cmd.heroku.get('/apps')
+        expect(request.getHeader(requestIdHeader)).to.deep.equal(',normal-request-id')
+      })
   })
 })