JSON format for load service incompatible with CLI kapacitor define command?

I am trying to setup an alert with template that will use both the load service and the CLI commands.
We need the load service so it will start automatically when we deploy the box and the CLI so users with only the permissions to run them (and not restarting the whole service) would be able to change the json parameters and re-define the alert.

The files I am using are:

├── kapacitor.conf
├── kapacitor_default.conf
└── load
├── handlers
│ └── childprocs.yaml
├── tasks
│ └── kp_childprocs.json
└── templates
└── kp_abnormal_state_percent_template.tick


// Which measurement to consume
var measurement string

// Optional where filter
var where_filter = lambda: TRUE

// Optional list of group by dimensions
var groups = [ * ]

// Expression to calculate the mean and use in the state comparison
var lambda_calc lambda

// Which field to process to trigger the alert
var stateLambda lambda

// How long this should happen before alerting
var stateDuration = 1m

// Critical criteria, the change of state
var crit = lambda: “state_duration” > 1

// How much data to window
var window = 5m

// Application name producing the alert
var application = ‘Unknown App’

// The topic to send the alerts
// var alert_topic topic

// The slack channel for alerts
var slack_channel = ‘#alerts_c

// Emoji to use in slack message
var slack_emoji = ‘’

// Local file to write the alerts
var log_alerts_file = ‘/tmp/alerts2.dat’

// Message the modified part
var message_part = 'Mean Lag: ’

// Topic to post the alerts
var topic = ‘state_percent_alert’

dbrp “stats”.“raw_data”

.message(’{{ .Time }} - {{ .Level }} “’ + message_part + '” {{ index .Fields “mean_field” | printf “%0.2f” }} in “’ + application + '”’)


topic: childprocs
id: childprocs
kind: slack
match: changed() == TRUE
channel: ‘#alerts_d


“template-id”: “kp_abnormal_state_percent_template”,
“vars”: {
“measurement”: {“type” : “string”, “value” : “appserv.childProcStats” },
“where_filter”: {“type”: “lambda”, “value”: ““app” =~ /x_server/”},
“groups”: {“type”: “list”, “value”: [{“type”:“string”, “value”:“app”}]},
“lambda_calc”: {“type”: “lambda”, “value” : ““procs_used” / “procs_avail” * 100” },
“stateLambda”: {“type” : “lambda”, “value” : ““mean_field” > 80” },
“stateDuration”: {“type” : “duration”, “value” : “1s”},
“crit”: {“type” : “lambda”, “value” : ““state_duration” > 1” },
“window”: {“type” : “duration”, “value”: “10s” },
“application”: {“type” : “string”, “value” : “x_server” },
“message_part”: {“type” : “string”, “value” : "Child proc usage above 80% for more than 1 s " },
“topic”: {“type”:“string”, “value”: “childprocs”}

The above format seems to work fine with the load service (I can see the alerting stream enabled and getting alerts).
However, if I try to do this:

[root@x-server01 kapacitor]# kapacitor define-template kp_tmp_template -tick load/templates/kp_abnormal_state_percent_template.tick
[root@x-server01 kapacitor]# kapacitor define kp_tmp_alert -template kp_tmp_template -vars load/tasks/kp_childprocs.json
invalid JSON in file load/tasks/kp_childprocs.json: json: cannot unmarshal string into Go value of type client.Var

Removing the:

“template-id”: “kp_abnormal_state_percent_template”,

part from kp_childprocs.json allows the define commands to run fine, but then the load service is not working for this alert.

Any ideas on what am I doing wrong here?

Thank you.

@pnikos You are doing it correctly, the JSON format is different between the CLI and the load versions of the var files. The load version needs the template id which for the CLI is provided as a command line argument instead of inside the JSON. Based on your use here maybe we could update the CLI to accept either form? It would be a small change to the CLI program. If you are interested I could give you some pointers on how to make such a change.

Hi @nathaniel,
Of course I am interested, please provide any hint on how to change this.


Great, here is the code that decodes the JSON for the CLI

That code expects JSON of the form:

You could add logic that if that fails to try and decode into this form instead:

If both fail you can report an error.

Thanks for helping out let us know how it goes.

I pushed this some days ago but not sure I can (or should) add specific reviewers.

Anyway, please check it, or tell me if I should do something from my side.
Sorry for the huge delay, this was the first time I saw golang code :smile: