Resolvers
Resolvers are classes that can are used to resolve an action taken on a Signal message. The clases themselves should not contain specific business logic, but rather encompass using a "technology" to solve the business problem.
An example would be the AWSLambda resolver. It knows how to forward the action inputs and other data associated with it to an AWS Lambda function. The logic to resolve the business requirements would be in that specific lambda function that is called.
Resolver Types
| Name | Description |
|---|---|
| Echo | Simply echos back the variables received in the Cue message. |
| AWSLambda | Calls an AWS Lambda function to resolve the Cue. |
| AWSStepFunction | Calls an AWS Step function to resolve the Cue. |
| AWSSystemManager | (Not Yet Implemented) Executes a command on an EC2 instance using the AWS System Manager agent. |
| Rest | (Not Yet Implemented) Sends the ResolverRequest to a REST Api via a POST request. |
Resolver Request
Each resolver receives the same information about the original Signal messages as well as the actions taken by the subscriber in regards to that message. Unless it isn't supported by the resolver, the input will be in JSON format (or a JSON Formated String).
Getting Important Information
Getting the data your resolver needs out of the ResolverRequest object can be a bit tricky. The majority of the information you will need is in the Signal and Actions elements, referenced by the ActionId and CueId values indicated. Below are code examples of how to get a few bits on information your resolver might want.
C#
public Status ProcessRequest(ResolverRequest request)
{
Status status = new Status();
// Any custom config passed in with the resolver
Dictionary<string, object> config = request.Signal.Cues[request.CueId].Resolver.Config;
// The variables specified by this specific request.
List<MultiValueVariable> variables = request.Actions[request.ActionId].Variables;
// ... Your Code Here...
return status;
}
Python
def lambda_handler(event, context):
# Any custom config passed in with the resolver
config = event['signal']['cues'][event['cueId']]['resolver']['config']
#The variables specified by this specific request.
variables = event['actions'][event['actionId']]['variables']
# ... Your Code Here ...
return {
'statusCode': 200
}
Class Diagram
Referenced Classes:
Json Schema
{
"$schema": "http://json-schema.org/draft-04/schema#",
"type": "object",
"required": [ "id", "actionId", "cueId", "signal", "actions" ],
"properties": {
"id": { "type": "string" },
"actionId": { "type": "string" },
"cueId": { "type": "string" },
"signal": {
*** Add Signal Json Schema Here ***
},
"actions": {
"type": "object",
"additionalProperties": {
"type": "object",
"required": [ "cueId", "variables", "time" ],
"properties": {
"cueId": { "type": "string"},
"variables": { "type": "array",
"items": [
{
"type": "object",
"properties": {
"name": { "type": "string" },
"values": { "type": "array",
"items": [ { "type": "string" } ]
}
}
}
]
},
"isValid": { "type": "boolean" },
"status": { "type": "string" },
"time": { "type": "string" }
}
}
},
"trace": { "type": "array",
"required": ["type"],
"properties": {
"type": { "type": "string"},
"object": { "type": "object" }
}
}
}
}
Field Descriptions
ResolverRequest
| Field | Type | Required | Description |
|---|---|---|---|
| id | String | Yes | The Id field of the Signal message. |
| actionId | String | Yes | The ActionId field of the reply sent from the subscribers. |
| cueId | String | Yes | The name of the CueOption in the Signal message that was selected by the subscriber on which the action was taken. |
| signal | Signal | Yes | The original signal message sent to the subscribers. |
| actions | Dictionary of ActionType | Yes | A dictionary of all actions taken against this signal (including the current action). |
| _trace | List of TraceObject | No | This is the "log" for all actions, updates, results associated with signal message. |
ActionType
| Field | Type | Required | Description |
|---|---|---|---|
| cueId | String | Yes | The CueOption that was selected for this action. |
| variables | List of MultiValueVariable | No | List of variables returned for this action. |
| isValid | Boolean | Yes | Flag to say if action was/is valid. |
| status | StatusType | Yes | Tells the current status of the action. |
| statusMessage | String | No | Message that describes the reason of the stauts. |
| time | DateTime | Yes | The time the action was taken. |
MultiValueVariable
| Field | Type | Required | Description |
|---|---|---|---|
| name | String | Yes | The variable name. |
| values | List of String | No | The value or values selected for the variable. |
TraceObject
| Field | Type | Required | Description |
|---|---|---|---|
| type | String | Yes | The object's type. |
| object | JSON Object | No | The Json Serialized version of the object. |
Examples
{
"id": "0X7ZKIFE4",
"actionId": "0X7ZN7XYF",
"cueId": "ec2",
"signal": {
"reporterId": "_default",
"routerId": "MyId",
"routerType": "MyIdType",
"name": "Utilization",
"description": "EC2 Utilization Montior",
"maxReplies": 1,
"cues": {
"ec2": {
"name": "EC2 Usage",
"description": "Server [i-888888888888] has been running for 7 days. Would you like to take action against it?",
"resolver": {
"name": "AWSLambda",
"notify": true,
"config": {
"name": "echo"
}
},
"inputs": [],
"actions": [
{
"name": "Perform Action",
"id": "ec2-action",
"description": "Choose action to take against EC2 instances.",
"type": "choice",
"values": {
"reboot": "Reboot Instance",
"terminate": "Terminate Instance",
"stop": "Stop Instance",
"hibernate": "Stop and Hibernate Instance"
},
"defaultValue": "stop"
},
{
"name": "Ignore Alert",
"id": "signal-action",
"description": "Ignore this alert.",
"type": "button",
"values": null,
"defaultValue": "ignore"
},
{
"name": "Disable Alert",
"id": "signal-action",
"description": "Disable this alert.",
"type": "button",
"values": null,
"defaultValue": "disable"
}
],
"defaultAction": "Perform Action",
"template": null,
"arguments": null
}
},
"defaultCue": null,
"defaultCueTimeout": 0,
"includeId": true
},
"actions": {
"0X7ZN7XYF": {
"cueId": "ec2",
"variables": [
{
"name": "ec2-action",
"values": [
"reboot"
]
}
],
"isValid": true,
"status": "New",
"time": "2020-10-07T20:02:09.0104309Z"
}
},
"trace": [
{
"type": "SignalReply",
"object": {
"id": "0X7ZKIFE4",
"time": "2020-10-07T20:00:10.609855Z",
"results": [
{
"channelType": "teams",
"code": "Success",
"message": "Success",
"channelId": "_defaultTeams"
},
{
"channelType": "slack",
"code": "Success",
"message": "Success",
"channelId": "_default"
}
],
"statusCode": "Success"
}
}
]
}