{"record":{"id":"9760c28597091d17","repo":"kataras/iris","slug":"failed-to-connect-to-the-server-after-d-retries-9760c2","errorCode":null,"errorMessage":"failed to connect to the server after %d retries","messagePattern":"failed to connect to the server after (.+?) retries","errorType":"exception","errorClass":null,"httpStatus":null,"severity":"error","filePath":"iris.go","lineNumber":1197,"sourceCode":"\n\t\t\t// Increase the retry interval by the base raised to the power of the number of attempts.\n\t\t\t/*\n\t\t\t\t0\t2 seconds\n\t\t\t\t1\t4 seconds\n\t\t\t\t2\t8 seconds\n\t\t\t\t3\t~16 seconds\n\t\t\t\t4\t~32 seconds\n\t\t\t\t5\t~64 seconds\n\t\t\t\t6\t~128 seconds\n\t\t\t\t7\t~256 seconds\n\t\t\t\t8\t~512 seconds\n\t\t\t\t...\n\t\t\t*/\n\t\t\tretryInterval = time.Duration(math.Pow(base, float64(i+1))) * time.Second\n\t\t}\n\t}\n\t// All attempts failed, return an error.\n\treturn fmt.Errorf(\"failed to connect to the server after %d retries\", maxRetries)\n}\n\n// https://ngrok.com/docs\nfunc (app *Application) tryStartTunneling() {\n\tif len(app.config.Tunneling.Tunnels) == 0 {\n\t\treturn\n\t}\n\n\tapp.ConfigureHost(func(su *host.Supervisor) {\n\t\tsu.RegisterOnServe(func(h host.TaskHost) {\n\t\t\tpublicAddrs, err := tunnel.Start(app.config.Tunneling)\n\t\t\tif err != nil {\n\t\t\t\tapp.logger.Errorf(\"Host: tunneling error: %v\", err)\n\t\t\t\treturn\n\t\t\t}\n\n\t\t\tpublicAddr := publicAddrs[0]\n\t\t\t// to make subdomains resolution still based on this new remote, public addresses.","sourceCodeStart":1179,"sourceCodeEnd":1215,"githubUrl":"https://github.com/kataras/iris/blob/7bedaf55a0b64bbb2248a5845a2c60d81a30996a/iris.go#L1179-L1215","documentation":"Application.tryConnect retries connecting to the configured server address up to maxRetries with exponential backoff (base^i seconds); if every attempt fails it returns 'failed to connect to the server after %d retries'. This is surfaced through app.Wait() when a caller waits for a server started asynchronously.","triggerScenarios":"Calling app.Wait() after app.Run/Spawn in a goroutine while the listener never becomes reachable within maxRetries * exponential intervals — e.g. app.Listen failed, wrong host/port configured, firewall blocking, or the server crashed during startup.","commonSituations":"Port already in use so the server never starts; connecting to 0.0.0.0/localhost mismatch inside Docker/Kubernetes before the pod is ready; firewalled ports; slow startup exceeding the retry budget (each retry grows as base^(i+1) seconds).","solutions":["Check the server actually started: look for earlier errors from app.Run (e.g. 'listen tcp: address already in use').","Verify the configured address/host matches where the server binds (localhost vs container hostname).","Increase the retry budget or wait interval if the service legitimately starts slowly.","Check firewall/security-group rules for the port.","In containers, use readiness probes / wait-for scripts instead of relying solely on tryConnect retries."],"exampleFix":"// before\napp.Run(iris.Addr(\":8080\"))\ngo app.Wait()\n// after: run and wait in the same flow, or check startup error first\nif err := app.Listen(\":8080\", iris.WithoutStartupLog); err != nil {\n    log.Fatalf(\"server failed to start: %v\", err)\n}","handlingStrategy":"retry","validationCode":"conn, err := net.DialTimeout(\"tcp\", addr, 2*time.Second)\nif err != nil {\n    log.Printf(\"target %s not reachable yet: %v\", addr, err)\n} else { conn.Close() }","typeGuard":null,"tryCatchPattern":"go app.Run(iris.Addr(addr))\nif err := app.Wait(); err != nil {\n    if strings.Contains(err.Error(), \"failed to connect\") {\n        log.Fatalf(\"server at %s never came up: %v\", addr, err) // check server logs for bind errors\n    }\n    log.Fatal(err)\n}","preventionTips":["Verify the port is free and the bind address matches the connect address.","In containers, wait for readiness before connecting.","Increase retry intervals for slow-starting services.","Always read the server's own startup errors alongside Wait()."],"tags":["go","iris","network","connection","startup"],"backgroundTag":"connection-refused","analyzedSha":"7bedaf55a0b64bbb2248a5845a2c60d81a30996a","analyzedAt":"2026-08-30T20:38:16.250Z","schemaVersion":2},"datasetVersion":"2026-08-30T23:17:21.991Z"}