passing more information to consul watch handler - consul

Question

I am wondering whether consul watch handler can be passed some dynamic information while it's called.
That means watch mechanism can pass the script more arguments instead of my given arguments like the below example.
{
"watches": [
{
"type": "service",
"args": ["/tmp/dosomething.sh", "how can i get responses from /v1/health/service here"]
}
]
}
By the way, when I want to 'watch' a service, the most important info to me is the service's state(passing or critial), but I don't understand:
when watch type is 'service', why I cannot appoint the 'service'.
when watch type is 'checks', why I cannot appoint state and service concurrently.

Answer 1

consul watch passes the entire API response payload as an argument to the watch handler script. Your script needs to be able to consume and parse the JSON, and then act on the data provided.
When you watch a service, the data returned is from the /v1/health/service/:service endpoint. (See consul/api/watch/funcs.go.)
when watch type is 'service', why I cannot appoint the 'service'.
I assume you mean that you would like to watch a specific service. If so, this is supported. You can specify a specific service to watch using the -service flag. For example, consul watch -type=service -service=assets.
when watch type is 'checks', why I cannot appoint state and service concurrently.
If you're interested in monitoring checks for a particular service, you should just use the aforementioned watch command for a specific service. The service check information is included in the API response.
$ consul watch -type=service -service=assets
[
{
"Node": {
"ID": "f013522f-aaa2-8fc6-c8ac-c84cb8a56405",
"Node": "hashicorp-consul-server-2",
"Address": "10.0.0.82",
"Datacenter": "dc2",
"TaggedAddresses": null,
"Meta": null,
"CreateIndex": 22898191,
"ModifyIndex": 22898191
},
"Service": {
"ID": "assets-v1",
"Service": "assets",
"Tags": [],
"Meta": null,
"Port": 9090,
"Address": "",
"Weights": {
"Passing": 1,
"Warning": 1
},
"EnableTagOverride": false,
"CreateIndex": 22898195,
"ModifyIndex": 22898195,
"Proxy": {
"MeshGateway": {},
"Expose": {}
},
"Connect": {}
},
"Checks": [
{
"Node": "hashicorp-consul-server-2",
"CheckID": "serfHealth",
"Name": "Serf Health Status",
"Status": "passing",
"Notes": "",
"Output": "Agent alive and reachable",
"ServiceID": "",
"ServiceName": "",
"ServiceTags": [],
"Type": "",
"Definition": {
"Interval": "0s",
"Timeout": "0s",
"DeregisterCriticalServiceAfter": "0s",
"HTTP": "",
"Header": null,
"Method": "",
"Body": "",
"TLSServerName": "",
"TLSSkipVerify": false,
"TCP": ""
},
"CreateIndex": 22898191,
"ModifyIndex": 22898191
}
]
}
]