Ubuntu Manpage: PLAINBOX_SESSION_SHARE - per-session runtime shared-state directory

NAME

       PLAINBOX_SESSION_SHARE - per-session runtime shared-state directory

SYNOPSIS

       Saving files to session share directory:

          ``command: do-something > $PLAINBOX_SESSION_SHARE/some-action.log``

       Loading files from session-share directory:

          ``command: cat $PLAINBOX_SESSION_SHARE/some-action.log``

DESCRIPTION

Plainbox sessions allow jobs to communicate by referring to the $PLAINBOX_SESSION_SHARE environment
variable. Files generated therein are explicitly meant to be accessible to all the other jobs
participating in the session.

Typical Use Cases
Typically a session will involve one or more pairs of jobs such as:

id: some-action
plugin: shell
summary: do something and save the log file to disk
commmand: do-something > $PLAINBOX_SESSION_SHARE/some-action.log

id: some-action-attachment
plugin: attachment
summary: log file of the do-something command
command: cat $PLAINBOX_SESSION_SHARE/some-action.log

The job some-action will use the do-something executable to perform some tests. The log file of that
action will be saved on the device executing the test, in the directory exposed through the environment
variable $PLAINBOX_SESSION_SHARE.

The some-action-attachment job will use that same directory and the agreed-upon name of the log file and
cat (1) it, which coupled with the plugin type shell will cause Plainbox to attach the log file to the
resulting document.

Checkbox Compatibility
Jobs designed to work with pre-Plainbox-based Checkbox may still refer to the old, somewhat confusing,
environment variable $CHECKBOX_DATA. It points to the same directory.

Multi-Node Sessions
When a test session involves multiple devices this directory is separately instantiated for each device.
Jobs executing on separate devices cannot use this facility to communicate. If communication is required
jobs are expected to use the LAVA-inspired, MPI-based communication API. For details see
plainbox-multi-node-api (7)

BUGS

       Within  the session directory the name of this directory is still CHECKBOX_DATA (literally, this is not a
       variable name). It may be changed at any point in time since jobs cannot form  any  meaningful  paths  to
       this directory without referring to either $PLAINBOX_SESSION_SHARE or $CHECKBOX_DATA

AUTHOR

       Zygmunt Krynicki & Checkbox Contributors

COPYRIGHT