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It is possible to obtain metric value changes in realtime, when metric value has exceeded or dropped below specified threshold. That can be done using alarms, which can be obtained via STOMP over Websocket by /alarm alarms event subscription.
Alarms can be managed using Websocket API or REST API
Alarm creation
A new alarm can be created with REST API query /api/alarm/create request
| API | Request | Response | Response status |
|---|
| WS API | |
...
|
|---|
| SEND
destination:/app/api/alarm/create
content-length:174
{
"requestId":"c71ec29d-b292-46c0-9138-a8ff434f2c3e",
"realm":"/api/alarm/create",
"payload":
{
"type":"0",
"name":"alarm1",
"value":"100000",
"metric":"3",
"node":"3",
"time":"1000"
}
} |
| |
...
...
user/service
content-type:application/json;charset=UTF-8
subscription:sub-1
message-id:3-51
content-length:84
{
"requestId":"c71ec29d-b292-46c0-9138-a8ff434f2c3e",
"status":200,
"reason":"SUCCESS"
} |
| 200 OK 400 Object not found 500 Persist exception |
| REST API | | Code Block |
|---|
| POST: /api/alarm/create "application/json; charset=utf-8"
{
|
|
...
...
...
...
...
...
...
...
...
...
...
200,
"reason":"SUCCESS"
} |
| 200 OK 400 Object not found 500 Persist exception |
Where
- type – alarm type:
- 0 – value has dropped below the threshold
- 1 – value has exceeded the threshold
- 2 - value is equal to threshold
- 4 - monotonically increasing value has decreased
- 5 - monotonically decreasing value has increased
- name – alarm name
- value – threshold value
- metric – metric identifier (for example, video bitrate)
- node – node identifier
- time – time in milliseconds during which the metric value must be above or below the threshold.
In the example above, an alarm, which is triggered if the video bitrate of the stream drops below 500 100 kbps for more than 5 seconds1 second, was created.
If node Id is not set, the alarm applies to all the nodes on backend server.
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An alarm parameters can be changed with REST API query /api/alarm/update request
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| Response | Response status |
|---|
| WS API | | Code Block |
|---|
| SEND
destination:/app/api/alarm/update
content-length:183
{
"requestId":"a60920eb-257a-451f-937f-1226a3856610",
"realm":"/api/alarm/update",
"payload":
{
"id":"6",
"type":"0",
"name":"alarm1",
"value":"100000",
"metric":"3",
"node":"3",
"time":"1000"
}
} |
| |
...
...
user/service
content-type:application/json;charset=UTF-8
subscription:sub-1
message-id:3-56
content-length:84
{
"requestId":"a60920eb-257a-451f-937f-1226a3856610",
"status":200,
"reason":"SUCCESS"
} |
| 200 OK 400 Object not found 500 Persist exception |
| REST API | | Code Block |
|---|
| POST: /api/alarm/update "application/json; charset=utf-8"
{
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...
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...
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...
...
...
...
...
...
...
...
...
| | Code Block |
|---|
| {
"status":200,
"reason":"SUCCESS"
} |
| 200 OK 400 Object not found 500 Persist exception |
Where
- id – alarm identifier
- type – alarm type:
- 0 – value has dropped below the threshold
- 1 – value has exceeded the threshold
- 2 - value is equal to threshold
- 4 - monotonically increasing value has decreased
- 5 - monotonically decreasing value has increased
- name – alarm name
- value – threshold value
- metric – metric identifier (for example, video bitrate)
- node – node identifier
- time – time in milliseconds during which the metric value must be above or below the threshold.
Alarm deletion
Alarm can be deleted with REST API query /api/alarm/delete request
| API | Request | Response | Response status |
|---|
| WS API | |
...
|
|---|
| SEND
destination:/app/api/alarm/delete
content-length:101
{
"requestId":"c108dbf9-35c0-42e5-814c-0eec57c4de8e",
"realm":"/api/alarm/delete",
"payload":
{
"id":"6"
}
} |
| |
...
...
user/service
content-type:application/json;charset=UTF-8
subscription:sub-1
message-id:3-57
content-length:84
{
"requestId":"c108dbf9-35c0-42e5-814c-0eec57c4de8e",
"status":200,
"reason":"SUCCESS"
} |
| 200 OK 400 Object not found 500 Persist exception |
| REST API | | Code Block |
|---|
| POST: /api/alarm/delete "application/json; charset=utf-8"
{
|
|
...
| | Code Block |
|---|
| {
"status":200,
"reason" |
|
...
| 200 OK 400 Object not found 500 Persist exception |
Where
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An alarm information can be obtained with REST API query /api/alarm/list request
| API | Request | Response | Response status |
|---|
| WS API | |
...
|
|---|
| SEND
destination:/app/api/alarm/list
content-length:98
{
"requestId":"d8e79851-85eb-4df1-bd3a-9f13090e8be5",
"realm":"/api/alarm/list",
"payload":
{
"id":""
}
} |
| |
...
...
user/service
content-type:application/json;charset=UTF-8
subscription:sub-1
message-id:3-60
content-length:177
{
"requestId":"d8e79851-85eb-4df1-bd3a-9f13090e8be5",
"status":200,
"reason":"SUCCESS",
"payload":[
{
"id":8,
"name":"alarm1",
"type":0,
"value":100000,
"time":1000,
"metric":3,
"node":3
}
]
} |
| 200 OK 400 Object not found 500 Persist exception |
| REST API | | Code Block |
|---|
| POST: /api/alarm/list |
|
...
"application/json; charset=utf-8"
{
"id":""
} |
| | Code Block |
|---|
| {
"status": 200,
"reason": "SUCCESS",
"payload": [
{
"id": 8,
"name": "alarm1",
"type": 0,
"value": 100000,
"time": 1000,
"metric": 3,
"node": 3
}
]
} |
| 200 OK 400 Object not found 500 Persist exception |
Where
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For every alarm, the response contains the same fields as /api/alarm/update query.request.
Alert message receiving
Alert messages are received if client is subscribed to /alarms queue. Alert message looks as follows:
| Code Block |
|---|
|
MESSAGE
destination:/alarms
content-type:application/json;charset=UTF-8
subscription:sub-0
message-id:4-187
content-length:242
{
"timestamp":1561101716609,
"status":"RAISED",
"alarmType":"LESS",
"alarmValue":700000,
"alarmName":"alarm1",
"mediaId":"617691c0-93f2-11e9-8808-938c74814152",
"metricEnumName":"VIDEO_RATE",
"metricValue":400232,
"nodeHostName":"test.flashphoner.com"
} |
Where:
- timestamp - time of alarm raised or cleared
- status - alarm state:
- RAISED - alarm is raised
- CLEARED - alarm is cleared
- alarmType - alarm type:
- LESS – value has dropped below the threshold
- MORE – value has exceeded the threshold
- EQUAL - value is equal to threshold
- MONOTONIC_UP - monotonically increasing value has decreased
- MONOTONIC_DOWN - monotonically decreasing value has increased
- alarmValue - alarm threshold value
- alarmName - alarm name
- mediaId - media session identifier for the stream which event is occured
- metricEnumName - metric name
- metricValue - metric value by which alarm was raised or cleared
- nodeHostName - server hostname on which the stream is published or played