SR_Winnow

Suppress Redundant Messages

Manual section:8
Date: January 2018
Version: 2.18.01a4
Manual group:MetPX-Sarracenia

SYNOPSIS

sr_winnow foreground|start|stop|restart|reload|status configfile sr_winnow cleanup|declare|setup configfile

DESCRIPTION

sr_winnow is a program that Subscribes to file notifications, and reposts the notifications, suppressing the redundant ones by comparing their fingerprints (or checksums.) The sum header stores a file's fingerprint as described in the sr_post(7) man page.

sr_winnow is an sr_subscribe(1) with the following options forced:

no-download True
suppress_duplicates on
accept_unmatch True

The suppress_duplicates lifetime can be adjusted, but it is always on.

sr_winnow connects to a broker (often the same as the posting broker) and subscribes to the notifications of interest. On reception if a notification, it looks up its sum in its cache. if it is found, the file has already come through, so the notification is ignored. If not, then the file is new, and the sum is added to the cache and the notification is posted.

sr_winnow can be used to trim messages from sr_post(1), sr_poll(1) or sr_watch(1) etc... It is used when there are multiple sources of the same data, so that clients only download the source data once, from the first source that posted it.

The sr_winnow command takes two argument: an action start|stop|restart|reload|status... (self described) followed by a configuration file described below.

The foreground is used when debugging a configuration, when the user wants to run the program and its configfile interactively... The foreground instance is not concerned by other actions. The user would stop using the foreground instance by simply pressing <ctrl-c> on linux or use other means to kill its process.

The actions cleanup, declare, setup can be used to manage resources on the rabbitmq server. The resources are either queues or exchanges. declare creates the resources. setup creates and additionnaly does the bindings of queues.

CONFIGURATION

In general, the options for this component are described by the sr_subscribe(1) page which should be read first. It fully explains the option configuration language, and how to find the option settings.

See sr_subscribe(1) for more details.

DEPRECATED

**interface -option formerly required in conjunction with vip. ** Now just scans all interfaces.

System Message: WARNING/2 (../sr_winnow.8.rst, line 76); backlink

Inline strong start-string without end-string.

SEE ALSO

sr_report(7) - the format of report messages.

sr_report(1) - process report messages.

sr_post(1) - post announcemensts of specific files.

sr_post(7) - The format of announcements.

sr_subscribe(1) - the download client.

sr_watch(1) - the directory watching daemon.

dd_subscribe(1) - the http-only download client.