#!/usr/bin/env bash
set -euo pipefail

AUTH_URL="https://api.example.com/auth/login"
API_URL="https://api.example.com/api/metrics"

get_access_token() {
  wget --quiet \
    --header="Content-Type: application/json" \
    --post-data='{"username":"user","password":"pass"}' \
    "${AUTH_URL}" \
    --output-document=- | jq -r '.accessToken'
}

ACCESS_TOKEN="$(get_access_token)"

wget --header="Authorization: Bearer ${ACCESS_TOKEN}" \
     "${API_URL}" \
     --output-document=metrics.json