Check the size of a github repo before downloading

check_github_repo_size

# http://webapps.stackexchange.com/questions/39587/view-estimated-size-of-github-repository-before-cloning
# tested on macOS
echo https://github.com/torvalds/linux.git | perl -ne 'print $1 if m!([^/]+/[^/]+?)(?:\.git)?$!' | xargs -I{} curl -s -k https://api.github.com/repos/'{}' | grep size

# output: 
# "size": 1746294,

I guess the size is in KBs?

curl -s https://api.github.com/repos/torvalds/linux | jq '.size' | numfmt --to=iec --from-unit=1024

What about private repos?

curl -s -H "Authorization: token GITHUB_TOKEN" https://api.github.com/repos/torvalds/linux | jq '.size' | numfmt --to=iec --from-unit=1024

curl -s -H "Authorization: Bearer <GITHUB_TOKEN>" https://api.github.com/repos/torvalds/linux | jq '.size' | numfmt --to=iec --from-unit=1024

I had to prefix Bearer last time I used this! 🎆

get_github_repo_size

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

get_github_repo_size() {

  if [[ "$1" == "--help" || "$1" == "-h" ]]; then
    echo "Usage: get_github_repo_size [OPTIONS] {GITHUB_REPO_URLS...}"
    echo
    echo "Retrieve and display the sizes of GitHub repositories."
    echo "The function will automatically use the GITHUB_TOKEN if it's set as an environment variable."
    echo
    echo "Options:"
    echo
    echo "  -h, --help     Display this help message."
    echo
    echo "Environment variables:"
    echo
    echo "  GITHUB_TOKEN   Use the provided GitHub token for authentication."
    echo
    echo "Exit codes:"
    echo
    echo "  0              Success"
    echo "  1              Fail"
    echo
    return
  fi

  local _i
  local  _err=0
  for _i in "${@}" ; do
    local _url="${_i}"
    local _owner="$(basename "$(dirname "${_url}")")"
    local _repo="$(basename "${_url}")"
    local _domain="$(basename "$(dirname "$(dirname "${_url}")")")"
    local _api_url="https://api.${_domain}/repos/${_owner}/${_repo}"

    local _headers=""
    if [ -n "$GITHUB_TOKEN" ]; then
      # Use the provided GitHub token if available
      local _headers="-H 'Authorization: Bearer $GITHUB_TOKEN'"
    fi

    # Fetch repository info, including size, in a single request
    local _response=$(curl -sS $_headers "$_api_url")

    # Check if the GitHub repo exists
    if jq -e '.message' <<< "$_response" >/dev/null; then
      # The API response contains a message field (indicating an error)
      local _message=$(jq -r '.message' <<< "$_response")
      >&2 printf 'error %s Failed to retrieve information about the GitHub repository: %s\n' "${_domain}/${_owner}/${_repo}" "${_message:-dns or http connection error}"
      _err=1
    else
      # The GitHub repo exists; fetch and format its size
      local _size=$(jq '.size' <<< "$_response")
      if [ "$_size" != "null" ]; then
        # Valid size found; format and print it
        printf '%s %s\n' "$(numfmt --to=iec --from-unit=1024 <<< "$_size")" "${_domain}/${_owner}/${_repo}"
      else
        >&2 printf 'error %s Invalid size data retrieved.\n'  "${_domain}/${_owner}/${_repo}"
        _err=1
      fi
    fi
  done
  return ${_err}
}

Example working usage:

$ get_github_repo_size "https://github.com/git/git" "https://github.com/danielmiessler/SecLists"

expected output:

To standard output Stream stdout Only

229M github.com/git/git
916M github.com/danielmiessler/SecLists

Example failing usage:

$ get_github_repo_size "https://github.com/gitx/git" "https://github.com/git/gitx" "https://mygithub.net/git/git"

Expected output:

To standard error Stream stderr Only

error github.com/gitx/git Failed to retrieve information about the GitHub repository: Not Found
error github.com/git/gitx Failed to retrieve information about the GitHub repository: Not Found
curl: (6) Could not resolve host: api.mygithub.net
error mygithub.net/git/git Failed to retrieve information about the GitHub repository: dns or http connection error

I've developed a tool for checking GitHub repository sizes by leveraging the GitHub API.
You can find the tool here:
GitHub Repository Size Checker

Based on what I've read, GitHub support has indicated that due to Git Alternates and the way files are stored in GitHub repositories, the numbers returned from the GitHub API cannot be relied upon for the actual size.