bash :: HTTP GET client (for healtcheck)

healthcheck.sh

#!/usr/bin/env bash

# example HTTP client. @author briceburg

main(){
  set -eo pipefail
  readonly __script=$(basename "$0")
  
  host="$(hostname -i || echo 'localhost')"
  port=8080
  path="/health"

  response="$(http:get "$host" "$port" "$path")"

  [ -n "$response" ] || die "http:get failed"
  [[ "$response" = *"HTTP/1.1 200 OK"* ]] || die "http:get $path failed to return 200"
  exit 0
}

http:get(){
  local host="${1:-localhost}"
  local port="${2:-80}"
  local path="${3:-/}"

  # open TCP connection
  exec 3<>/dev/tcp/$host/$port

  # make HTTP 1.1 request to path
  printf "GET $path HTTP/1.1\nHost: $host\nUser-Agent: $__script\n\n" >&3

  # print response (including headers)
  while IFS= read -t 1 -u 3 line; do
    echo "$line"
  done

  exec 3<&-
}

log(){ echo -e "$__script: $*" >&2; }
die(){ log "$*"; exit 1; }

main "$@"