rules.md

Rules management

The Kuiper rule command line tools allows you to manage rules, such as create, show, drop, describe, start, stop and restart rules.

create a rule

The command is used for creating a rule. The rule's definition is specified with JSON format, read rule for more detailed information.

create rule $rule_name $rule_json | create rule $rule_name -f $rule_def_file

The rule can be created with two ways.

• Specify the rule definition in command line.

Sample:

# bin/cli create rule rule1 {"sql": "SELECT * from demo","actions": [{"log":  {}},{"mqtt":  {"server":"tcp://127.0.0.1:1883", "topic":"demoSink"}}]}

The command create a rule named rule1.

• Specify the rule definition in file. If the rule is complex, or the rule is already wrote in text files with well organized formats, you can just specify the rule definition through -f option.

Sample:

# bin/cli create rule rule1 -f /tmp/rule.txt

Below is the contents of rule.txt.

{
  "sql": "SELECT * from demo",
  "actions": [
    {
      "log": {}
    },
    {
      "mqtt": {
        "server": "tcp://127.0.0.1:1883",
        "topic": "demoSink"
      }
    }
  ]
}

show rules

The command is used for displaying all of rules defined in the server with a brief status.

show rules

Sample:

# bin/cli show rules
[
  {
    "id": "rule1",
    "status": "Running"
  },
  {
     "id": "rule2",
     "status": "Stopped: canceled by error."
  }
]

describe a rule

The command is used for print the detailed definition of rule.

describe rule $rule_name

Sample:

# bin/cli describe rule rule1
{
  "sql": "SELECT * from demo",
  "actions": [
    {
      "log": {}
    },
    {
      "mqtt": {
        "server": "tcp://127.0.0.1:1883",
        "topic": "demoSink"
      }
    }
  ]
}

drop a rule

The command is used for drop the rule.

drop rule $rule_name

Sample:

# bin/cli drop rule rule1
Rule rule1 is dropped.

start a rule

The command is used to start running the rule.

start rule $rule_name

Sample:

# bin/cli start rule rule1
Rule rule1 was started.

stop a rule

The command is used to stop running the rule.

stop rule $rule_name

Sample:

# bin/cli stop rule rule1
Rule rule1 was stopped.

restart a rule

The command is used to restart the rule.

restart rule $rule_name

Sample:

# bin/cli restart rule rule1
Rule rule1 was restarted.

get the status of a rule

The command is used to get the status of the rule. If the rule is running, the metrics will be retrieved realtime. The status can be

• $metrics
• stopped: $reason

getstatus rule $rule_name

Sample:

# bin/cli getstatus rule rule1
{
    "source_demo_0_records_in_total":5,
    "source_demo_0_records_out_total":5,
    "source_demo_0_exceptions_total":0,
    "source_demo_0_process_latency_ms":0,
    "source_demo_0_buffer_length":0,
    "source_demo_0_last_invocation":"2020-01-02T11:28:33.054821",
    ... 
    "op_filter_0_records_in_total":5,
    "op_filter_0_records_out_total":2,
    "op_filter_0_exceptions_total":0,
    "op_filter_0_process_latency_ms":0,
    "op_filter_0_buffer_length":0,
    "op_filter_0_last_invocation":"2020-01-02T11:28:33.054821",
    ...
}

get the topology structure of a rule

The command is used to get the status of the rule represented as a json string. In the json string, there are 2 fields:

• sources: it is a string array of the names of all source nodes. They are the entry of the topology.
• edges: it is a hash map of all edges categorized by nodes. The keys are the starting point of an edge. And the value is a collection of ending point.

gettopo rule $rule_name

Sample result:

{
  "sources": [
    "source_stream"
  ],
  "edges": {
    "op_preprocessor_stream": [
      "op_project"
    ],
    "op_project": [
      "sink_log"
    ],
    "source_stream": [
      "op_preprocessor_stream"
    ]
  }
}