"Proxy handler: unable to reach app" on hot-reload

[bjornkpu]

Problem

The runner takes ages to start the application and in the meantime the proxy is trying to reload the browser, thus hitting the error Proxy handler: unable to reach app. in the browser.

The timeings:

The go build is ~instant.
The air runner takes ~8 seconds.
The go application starts in 2.5 milli seconds.

Making me think the problem lies in the air runner.

Steps to reproduce:

1. Start air with proxy enabled.
2. Have the browser window on the proxy port
3. make a change to trigger air restart
4. se the browser display the error

Video

Here is a video of the process
https://github.com/user-attachments/assets/caac648c-1279-441d-b347-47aaf4abbc71

Expected behavior

To reload the browser after the app is up and running.

Actual Behavior

The browser reload too early, hits the error, and stops refreshing. A manual refresh is required.

Additional information

My .air.toml:

root = "."
tmp_dir = "tmp"

[build]
  args_bin = []
  bin = "tmp/main.exe"
  cmd = "go build -o ./tmp/main.exe cmd/server/main.go"
  delay = 1000
  exclude_dir = [".idea", "db", "docs", "tmp"]
  exclude_file = []
  exclude_regex = ["_test.go"]
  exclude_unchanged = true
  follow_symlink = false
  full_bin = ""
  include_dir = []
  include_ext = ["go"]
  include_file = []
  kill_delay = "0s"
  log = "build-errors.log"
  poll = false
  poll_interval = 0
  post_cmd = []
  pre_cmd = []
  rerun = false
  rerun_delay = 500
  send_interrupt = false
  stop_on_error = false

[color]
  app = ""
  build = "yellow"
  main = "magenta"
  runner = "green"
  watcher = "cyan"

[log]
  main_only = false
  time = false

[misc]
  clean_on_exit = false

[proxy]
  app_port = 8080
  enabled = true
  proxy_port = 8081

[screen]
  clear_on_rebuild = true
  keep_scroll = true

My run configuration

My system

Go version: 1.23.1
Air version: v4.12.0
GoLand version: 2024.2.2.1
Powershell version: 5.1
OS Name Microsoft Windows 11 Enterprise
OS Version: 10.0.22631 N/A Build 22631
System Manufacturer: LENOVO
System Model: 21BUS1BC00
System Type: x64-based PC
BIOS Version: LENOVO N3BET61W (1.39 ), 30.04.2024
Processor(s): 1 Processor(s) Installed. [01]: Intel64 Family 6 Model 154 Stepping 3 GenuineIntel ~1711 Mhz
Total Physical Memory: 32 434 MB