go-client-server

A Go Client-Server local application with Concurrency

go-client-server is a local application capable of implementing a RESTful http server listening for requests on localhost:6969 or a concurrent client-server application with a RabbitMQ's external queue as an orchestrator/work queue.

The server implements an ordered map data structure to store and retrieve key->value pairs in order of addition. Clients - either via RabbitMQ or http - can ask the server to perform any of the following operations:

• Add item
• Remove item
• Get item
• Get item by index
• Get all items

For documentation on how to structure server requests, for both server types, see the client README.

Prequisites

1. Golang.
2. Docker Engine.
3. RabbitMQ server running for non-http server. More information below.

Install and Run

The repo comes with a pre-built binary go-client-server that is ready to run. Simply clone the repo, ensure you meet the requirements, and run it.

The http server can run out of the box if the -server-type http flag is passed (see usage below), but for the concurrent client-server execution mode, the RabbitMQ server needs to be running.

Once Docker Engine is installed, simply run the script to start a container of the RabbitMQ local server:

./scripts/run_rabbitmq_server.sh

Usage

To run the binary:

go-client-server [server_mode_flag] [sleep_flag] [non_sequential_flag]

Flags

go-client-server takes 3 optional flags:

• -server-type
  • If passed the value http, the application spins up an http server instead.
  • Any other value (or the absence of the flag) defaults to a RabbitMQ client-server application.
  • If present and passed the value of http, all other flags are ignored.
• -sleep
  • If present, workers will simulate a "heavy" task by randmoly waiting 1-5 seconds before executing the work.
  • This delay will be applied to all methods except getall.
• -non-sequential
  • If present, the work queue will dispatch messages to workers without receiving acknowledgemnts.
  • Note: This may impact the sequentiality of operations passed to the data structure, espcially if -sleep is present.

Logs and results

The http server does not write any logs. It just prints to stdout or to the request writer.

For the client-server with RabbitMQ application, errors are written to stdout. Information ([INFO]), warning ([WARN]), and results ([RESULT]) are written to the appropriate logfile under logs/.

go-client-server will create and write to a different logfile based on the configurations passed. The options are:

• logs/server.log for default mode.
• logs/sleep_nonSequential_server.log when the -non-sequential and -sleep flags are present.
• logs/nonSequential_server.log when only the -non-sequential flag is present.
• logs/sleep_server.log when only the -sleep flag is present.

Each log will contain information about the request, the Goroutine ID processing it, and how many goroutines are running at any time. For a sleep_nonSequential_server.log example:

[INFO] 2023/03/26 03:24:58 handlers.go:82: Goroutine ID: 15
[RESULT] 2023/03/26 03:24:58 handlers.go:84: Got All Items: [map[C:c] map[D:d] map[X:x]]
[INFO] 2023/03/26 03:24:58 utils.go:36: Goroutines running at the end of GID 15 WORKER: 13

[INFO] 2023/03/26 03:24:58 handlers.go:16: Goroutine ID: 10
[RESULT] 2023/03/26 03:24:58 handlers.go:19: New orderedmap entry: A->a
[INFO] 2023/03/26 03:24:58 utils.go:36: Goroutines running at the end of GID 10 WORKER: 12

[INFO] 2023/03/26 03:24:58 handlers.go:32: Goroutine ID: 13
[RESULT] 2023/03/26 03:24:58 handlers.go:37: Removed D->d from ordered map
[INFO] 2023/03/26 03:24:58 utils.go:36: Goroutines running at the end of GID 13 WORKER: 11