csw-event-cli

A command line application that facilitates interaction with Event Service. It accepts various commands to publish and subscribe to events.

Supported Commands

• inspect
• get
• publish
• subscribe

inspect

Takes a comma separated list of events and displays each event’s parameter information which includes key name, key type, and unit along with metadata (event key, timestamp & id).

• -e, --events : comma separated list of events to inspect

Examples:

csw-event-cli inspect -e wfos.prog.cloudcover,wfos.prog.filter

get

Takes a comma separated list of events with nested key paths and displays event information including values either in oneline or JSON format.

• -e, --events comma separated list of events in the form of <event1:key1>,<event2:key2:key3>, use : to separate multiple keys for same event. Ex. -e a.b.c:struct1/ra,x.y.z:struct2/dec:epoch
• -o, --out output format, default is oneline
• -t, --timestamp display timestamp
• --id display event id
• -u, --units display units

Examples:

1. csw-event-cli get -e wfos.prog.cloudcover
   

   Displays all keys information in oneline form for event wfos.prog.cloudcover

2. csw-event-cli get -e wfos.prog.cloudcover:struct1/ra:epoch -t --id -u
   

   Displays information of only struct1/ra and epoch keys as well as timestamp, event id and units of provided keys in oneline form for event wfos.prog.cloudcover

3. csw-event-cli get -e wfos.prog.cloudcover:epoch,wfos.prog.filter:ra
   

   Displays information of epoch of event wfos.prog.cloudcover and ra key of event wfos.prog.filter:ra

4. csw-event-cli get -e wfos.prog.cloudcover:epoch -o json
   

   Displays event wfos.prog.cloudcover with only epcoh key in JSON format.

publish

Publishes an event to the Event Server from the provided input data file or CLI params.

• -e, --event event key to publish
• --data absolute file path which contains event in JSON format
• --params pipe ‘|’ separated list of params enclosed in double quotes in the form of "keyName:keyType:unit=values| ...". unit is optional here. Supported key types are: [i = IntKey | s = StringKey | f = FloatKey | d = DoubleKey | l = LongKey | b = BooleanKey]. You can optionally choose to enclose param values in [, ] brackets. Values of a string key should be provided in single quotes and use backslash to escape string. Ex. "addressKey:s=['Kevin O\'Brien','Chicago, USA']|timestampKey:s=['2016-08-05T16:23:19.002']"
• -i, --interval interval in milliseconds to publish event. A single event will be published, if not provided
• -p, --period publish events for this duration in seconds on provided interval. Default is 2147483 seconds.

Examples:

1. csw-event-cli publish -e wfos.prog.cloudcover --data /path/to/event.json
   

   Creates event from provided JSON file and publishes it with key wfos.prog.cloudcover to the Event Server.

2. csw-event-cli publish -e wfos.prog.cloudcover --data /path/to/event.json -i 500 -p 60
   

   Creates an Event from provided JSON file and publishes it every 500ms for duration of 60s.

3. csw-event-cli publish -e wfos.prog.cloudcover --params "k1:s=['Kevin O\'Brien','Chicago, USA']|k2:s=['2016-08-05T16:23:19.002']"
   

   First fetches already published Event for key wfos.prog.cloudcover from the Event Server and then updates that Event with provided --params If provided keys are already present in existing Event, then those will be updated. Otherwise, new param entries will be added to the Event. If no Event is published in past for the provided key, then the new Event gets created with the provided params and Event key.

subscribe

Takes a comma separated list of Events with nested key paths and displays continuous stream of Event information as soon as it receives the Event.

• -e, --events comma separated list of Events in the form of <event1:key1>,<event2:key2:key3>, use : to separate multiple keys for the same Event. Ex. -e a.b.c:struct1/ra,x.y.z:struct2/dec:epoch
• -i, --interval interval in milliseconds which to receive an Event
• -o, --out output format, default is oneline
• -t, --timestamp display timestamp
• --id display event id
• -u, --units display units

Examples:

1. csw-event-cli subscribe -e wfos.prog.cloudcover
   

   Subscribes to Event key wfos.prog.cloudcover and displays all key information as soon as there is an Event published for key wfos.prog.cloudcover with the oneline format.

2. csw-event-cli subscribe -e wfos.prog.cloudcover:struct1/ra:epoch -t --id -u
   

   Subscribes to the Event key wfos.prog.cloudcover and displays information of only the struct1/ra and epoch keys along with timestamp, event id and units of tge provided keys in oneline format as soon as there is an Event published for the key wfos.prog.cloudcover.

3. csw-event-cli subscribe -e wfos.prog.cloudcover -i 500
   

   Subscribes to the Event key wfos.prog.cloudcover and displays all key information at provided interval <500ms>. Irrespective of whether there are multiple Events published for the key wfos.prog.cloudcover within 500ms interval or not, at every tick (i.e. 500ms), the latest Event information will be displayed on the console.

4. csw-event-cli subscribe -e wfos.prog.cloudcover:epoch -o json
   

   Subscribes to Event key wfos.prog.cloudcover and displays only epoch key information as soon as there is an Event published for key wfos.prog.cloudcover, in JSON format.

About this application

--help

Prints the help message.

--version

Prints the version of the application.

Testing/Development

While testing or development, in order to use this CLI application, below prerequisites must be satisfied:

• csw-location-server application is running.
• csw-location-agent application is running, which has started the Event Server and registered it to the Location Service.

Please refer to Starting Apps for Development section for more details on how to start these applications using csw-services.sh script.

Monitor statistics

Event Service uses redis as the event store. Using redis-cli, you can monitor continuous stats about the Event Service.

$ redis-cli --stat
------- data ------ --------------------- load -------------------- - child -
keys       mem      clients blocked requests            connections
305        20.70M   605     0       1771418 (+0)        615
305        20.71M   605     0       1825363 (+53945)    615
305        20.70M   605     0       1877638 (+52275)    615
305        20.71M   605     0       1910198 (+32560)    615
305        20.71M   605     0       1960837 (+50639)    615
305        20.74M   605     0       2001565 (+40728)    615

In the above example, a new line is printed every second with useful information, including the difference between current and old data points.

• keys: Represents all the keys present in the Redis database, which in case of the Event Service are EventKeys
• clients: Represents total number of clients currently connected to the Redis server
• requests: Represents total number of Redis commands processed along with a delta between every interval, specified with the -i option (see below)
• connections: Represents total number of socket connections opened to the Redis server

The -i <interval> option in this case works as a modifier in order to change the frequency at which new lines are emitted. The default is one second.

You can explicitly pass the hostname and port of the Redis server while running redis-cli

$ redis-cli -h redis.tmt.org -p 6379

A detailed list of operations you can perform with redis-cli can be found here