Creating a ZEO server

PyAMS primarilly relies on a ZODB database to it’s store itt’s configuration. Other packages may rely on another database, but PyAMS_content package also stores it’s contents in a ZODB.

As some PyAMS packages start concurrent processes (“synchronization” is done via ØMQ), concurrent accesses are required on the ZODB (event when you start your application in “single process” mode) and a ZEO server have to be started.

Creating initial buildout

PyAMS provides a ZEO server scaffold, called zeo_server, generated via a cookiecutter template.

A simple option to create a ZEO server is to create a buildout environment including ZEO and ZODB packages:

# mkdir /var/local/
# pip3 install virtualenv
# virtualenv --python=python3.5 env
# cd env
# . bin/activate
(env) # pip3.5 install cookiecutter
(env) # cookiecutter hg+http://hg.ztfy.org/pyams/scaffolds/zeo_server

CookieCutter will ask you for a small set of input variables that you can change or not:

  • pyams_release: version of PyAMS configuration file to use. “latest” (default value) will point to last release; you can also choose to point to a given release (“0.1.4” for example)
  • project_name: current environment name in “human form”
  • project_slug: “technical” package name, based on project name
  • eggs_directory: relative or absolute path to directory containing downloaded eggs; this directory can be shared with other projects (“eggs” as default)
  • run_user: user name under which Apache process will run (“www-data” as default)
  • run_group: group name under which Apache process will run (“www-data” as default)
  • zeo_server_port: listening port of ZEO server (“8100” as default)
  • zeo_monitor_port: listening port of ZEO monitor (“8101” as default)
  • zeo_storage: name of first ZEO storage; default value is based on project name
  • use_zeo_auth: specify if ZEO authentication should be used
  • zeo_auth_user: name of ZEO authenticated user (if ZEO authentication is used)
  • zeo_auth_password: password of ZEO authenticated user (if ZEO authentication is used)
  • zeo_pack_report: email address to which pack reports should be sent
  • logs_directory: absolute path to directory containing ZEO’s log files.

A message is displayed after initialization to finalize environment creation:

ZEO server configuration

All ZEO configuration files are generated in “etc” subdirectory. These includes:

  • etc/zeo_server-zdaemon.conf: ZDaemon configuration file
  • etc/zeo_server-zeo.conf: ZEO server configuration file
  • etc/auth.db: ZEO authentication file; WARNING: this file is not created automatically, you have to create it after buildout.

In these file names, always replace “zeo_server” with the value which was given to “project_slug” variable during CookieCutter template creation.

ZEO server tools

A set of system configuration files are produced to handle your ZEO environment. These includes:

  • etc/init.d/zeo-zeo_server: ZEO server start/stop script in Init-D format. Create a link to this file in /etc/init.d and update Init.d scripts (update-rc.d zeo-zeo_server defaults) to include ZEO in server start/stop

    process. You can also use this script to start/stop ZEO by hand with start and stop arguments.

  • etc/systemd/zeo-zeo_server.service: SystemD service configuration file for ZEO server. Create a link to this file in /etc/systemd/system and reload SystemD daemon (systemctl daemon-reload) before activating ZEO service (systemctl enable zeo-zeo_server.service and systemctl start zeo-zeo_server.service).

  • etc/logrotate.d/zeo-zeo_server: LogRotate configuration file for ZEO log files. Create a link to this file in /etc/logrotate.d to activate log rotation for ZEO server.

  • etc/cron.d/pack-zeo-zeo_server: Cron configuration file for ZEO database packing. Just create a link to this file in /etc/cron.d directory to enable ZODB packing on a weekly basis (by default).

In these file names, always replace “zeo_server” with the value which was given to “project_slug” variable during CookieCutter template creation. All directory names are those used on a Debian GNU/Linux distribution and may have to be changed on other distributions.