Await IPv4 Address

await-ipv4-address.sh, contains a function that returns listening ports for a given service, even if it has to wait a few seconds, and even if the listening ports are not known in advance; such as in the case with librespot service.

The following covers how to install this branch as a submodule within your own project, and parameters that await-ipv4-address.sh currently responds to.

Quick Start

Bash Variables

_module_https_url='https://github.com/network-utilities/await-ipv4-address.git'
_module_relative_path='lib/modules/await-ipv4-address'

Git Commands

cd "your-project-path"

git submodule add\
 -b master\
 --name await-ipv4-address\
 "${_module_https_url}" "${_module_relative_path}"

Version Locking; recommended for those that audit every dependency...

git checkout tags/<tag_name> -b <branch_name>

... replace <tag_name> with the tag to checkout and <branch_name> with a custom name, eg...

git checkout tags/v0.0.1 -b loc-v0.0.1

Edit Your ReadMe File

Suggested additions so everyone has a good time with submodules

Clone with the following to avoid incomplete downloads


    git clone --recurse-submodules <url-for-your-project>


Update/upgrade submodules via


    git submodule update --init --recursive --remote --merge


Please review the official documentation for Git submodules...


    git help submodule


... or via [Submodules chapter][git_book__submodules] from Git.



[git_book__submodules]:
  https://git-scm.com/book/en/v2/Git-Tools-Submodules
  "Valuable information for daily use and recovering from a detached HEAD"

Example Bash Script

example-usage.sh

#!/usr/bin/env bash


## Enable sourcing via absolute path
__SOURCE__="${BASH_SOURCE[0]}"
while [[ -h "${__SOURCE__}" ]]; do
    __SOURCE__="$(find "${__SOURCE__}" -type l -ls | sed -n 's@^.* -> \(.*\)@\1@p')"
done
__DIR__="$(cd -P "$(dirname "${__SOURCE__}")" && pwd)"


source "${__DIR__}/modules/await-ipv4-address/await-ipv4-address.sh"


## Lists iptables rules targeting IP, waits up-to seven seconds for an IP on eth0 interface
something_networky(){
    local _assigned_ips=($(await_ipv4_address 'eth0' '1' '6'))
    if [ -z "${_assigned_ips}" ]; then
        printf '%s got board of waiting for an IP\n' "${FUNCNAME[0]}"
        return 1
    fi

    for _assigned_ip in "${_assigned_ips[@]}"; do
        printf 'Listing any iptables rules for -> %s\n' "${_assigned_ip%/*}"
        iptables -S | grep -- "${_assigned_ip%/*}"
    done
}


something_networky

Testing example-usage.sh

bash example-usage.sh || echo "Exit code -> ${?}"

Utilize the above example to make similar edits to any of your project scripts that should wait for an IP.

Commit and Push

git add .gitmodules
git add lib/modules/await-ipv4-address
git add README.md


git commit -F- <<'EOF'
:heavy_plus_sign: Adds network-utilities/await-ipv4-address dependency



**Additions**


- `.gitmodules` file, tracks other Git repository code utilized by this project

- `lib/modules/await-ipv4-address` submodule, Git tracked dependency


**Edits**


- `README.md` file, documentation updates for submodules
EOF


git push origin gh-pages

🎉 Excellent 🎉 your project is now ready to begin unitizing code of this repository!