Deploy From Gitlab To FTP Server

Create file gitlab-ci.yml in gitlab

variables:
  HOST: "yourFTPServer"
  USERNAME: "yourFTPServerUsername"
  PASSWORD: "yourFTPServerPassword"

deploy:
  script:
    - apt-get update -qq && apt-get install -y -qq lftp
    - lftp -c "set ftp:ssl-allow no; open -u $USERNAME,$PASSWORD $HOST; mirror -Rnev ./ ./htdocs --ignore-time --parallel=10 --exclude-glob .git* --exclude .git/"
  only:
    - master

NOTE: Make sure to change host, username, password and directory name where to deploy code

Ref: https://stackoverflow.com/questions/49632077/use-gitlab-pipeline-to-push-data-to-ftpserver