curl, PowerShell and Python

All three examples send the same card in the GGspeak format, with a key: running it again with state set to ok updates the card. The link comes from an environment variable, GGSPEAK_WEBHOOK.

curl

curl -fsS -X POST "$GGSPEAK_WEBHOOK" \
  -H "Content-Type: application/json" \
  -d '{
    "key": "nightly-backup",
    "card": {
      "title": "Nightly backup",
      "state": "alert",
      "body": "pg_dump failed: no space left on device",
      "fields": [{ "name": "Server", "value": "sp-1" }]
    }
  }'

-f makes curl exit with an error on 4xx and 5xx responses, and -S shows the message even with -s. To see the error body, drop the -f.

PowerShell 5.1

# Windows PowerShell 5.1 may default to an old TLS version.
[Net.ServicePointManager]::SecurityProtocol = [Net.SecurityProtocolType]::Tls12

$body = @{
  key  = 'nightly-backup'
  card = @{
    title  = 'Nightly backup'
    state  = 'alert'
    body   = 'pg_dump failed: no space left on device'
    fields = @(@{ name = 'Server'; value = 'sp-1' })
  }
} | ConvertTo-Json -Depth 5

try {
  # Send UTF-8 bytes: without this, 5.1 mangles accented characters.
  Invoke-RestMethod -Method Post -Uri $env:GGSPEAK_WEBHOOK `
    -ContentType 'application/json; charset=utf-8' `
    -Body ([System.Text.Encoding]::UTF8.GetBytes($body))
} catch {
  # In 5.1 the error body lives in ErrorDetails.
  Write-Error $_.ErrorDetails.Message
}

On success the response is 204 and Invoke-RestMethod returns nothing. With ?wait=true in the URL it returns the message as an object.

Python

import os
import requests

payload = {
    "key": "nightly-backup",
    "card": {
        "title": "Nightly backup",
        "state": "alert",
        "body": "pg_dump failed: no space left on device",
        "fields": [{"name": "Server", "value": "sp-1"}],
    },
}

r = requests.post(os.environ["GGSPEAK_WEBHOOK"], json=payload, timeout=10)

if r.status_code == 429:
    try:
        wait = r.json()["retry_after"]  # seconds, with decimals
    except (ValueError, KeyError, TypeError):  # a 429 from a proxy, without the GGspeak body
        wait = r.headers.get("Retry-After", "1")
    print(f"Rate limited. Try again in {wait} s.")
elif not r.ok:
    try:
        err = r.json()
        print(f"{err['code']}: {err['message']} ({err['docs']})")
    except (ValueError, KeyError, TypeError):  # gateway error, not JSON
        print(f"HTTP {r.status_code}: {r.text[:200]}")

requests already sends Content-Type: application/json and encodes UTF-8 when you use json=. r.ok is true on 204.

To mark it ok when the script finishes fine, send another POST with the same key and "state": "ok" (the card turns resolved). Error codes are in Errors.