Have gpg fetch key password using 1Password CLI

pinentry-op.bash

#!/usr/bin/env bash

# Have gpg fetch key password using 1Password CLI.
#
# 1. Add to ~/.gnupg/gpg-agent.conf:
#
#   pinentry-program <path to this file>
#
# 2. Export OP_GPG_PASSWORD_ENTRY_<key-id>=<key-password-reference> variables :
#
#   export OP_GPG_PASSWORD_ENTRY_22129EAMD723DCC8=op://Employee/asklnfnf234njndsf9asd09asd/password
#   export OP_GPG_PASSWORD_ENTRY_34532D9A9ASKMNC3=op://Employee/q9wardafja8s9f8sdfshdfhsfd/password
#
# You may have to kill the agent for it take effect:
#
#   gpg-connect-agent killagent
#
# If you ever want to change this file, export LOG=<some-path> to see how gpg runs it.
#
# Derived from https://gist.github.com/wmudge/422660bcb3dbd767ad4219a5d471ea38

: ${PINENTRY_OP_LOG_FILE:=~/.gnupg/pinentry-op.log}

function log {
  echo "[pinentry-op] $@" >> "$PINENTRY_OP_LOG_FILE"
}

echo "OK"

while read cmd val; do
  log "$cmd $val"
  case "$cmd" in
    \#*)
      ;;
    SETDESC)
      key_id="$(echo "$val" | sed -E 's/.*ID ([A-Z0-9]+).*/\1/')"
      key_var="OP_GPG_PASSWORD_ENTRY_$key_id"
      log "Detected key ID $key_id, var $key_var (value ${!key_var})"
      OP_GPG_PASSWORD_ENTRY_CURRENT="${!key_var}"
      ;;
    GETPIN)
      COMMAND="op read $OP_GPG_PASSWORD_ENTRY_CURRENT"
      log "Executing '$COMMAND'"
      echo "D $($COMMAND)"
      ;;
    SETERROR)
      echo "ERR 31 Invalid passphrase"
      ;;
    BYE)
      exit 0
      ;;
    *)
      echo
      ;;
  esac
  echo "OK"
done