create cloudwatch dashboard with boto3 using lambda

Question

i want to create cloudwatch dashboard for multiple EC2 i have problem to put JSON dashboard bady and make region and id instance value be variable

the code

from __future__ import print_function

import json

import boto3

def lambda_handler(event, context):

    ec2_client = boto3.client('ec2')
    CW_client = boto3.client('cloudwatch', region_name='eu-west-1')

    regions = [region['RegionName']
               for region in ec2_client.describe_regions()['Regions']]
    for region in regions:
        print('Instances in EC2 Region {0}:'.format(region))
        ec2 = boto3.resource('ec2',region_name=region)

        instances = ec2.instances.filter(
            Filters=[
                {'Name': 'tag:backup', 'Values': ['true']}
            ]
        )
        for i in instances.all():
            #for ID in i.InstanceId.all():
            print(i.id)
            instance_id = i.id
            response = CW_client.put_dashboard(DashboardName='test', DashboardBody='{"widgets": [{"type": "metric", "x": 12, "y": 0, "width": 12, "height": 6, "properties": {"metrics": [[ "AWS/EC2", "CPUUtilization", "InstanceId", instance_id ]], "view": "timeSeries", "stacked": false, "region": region, "stat": "Average", "period": 60, "title": "CPUUtilization" }}]}')

the error

  "errorMessage": "An error occurred (InvalidParameterInput) when calling the PutDashboard operation: The field DashboardBody must be a valid JSON object",
  "errorType": "DashboardInvalidInputError",

Answer 1

Your DashboardBody contains the literal string instance_id and region (without quotes). That's why the JSON is invalid. You need the values of instance_id and region , not the bare words instance_id and region .

You should use string interpolation. For example:

region = "us-east-1"
instance_id = "i-1234567890"

partbody = '{"region":"%s", "instance_id":"%s"}' % (region, instance_id)

Or you could use f-strings but then you'd have to quote the braces, like so:

partbody = f'{{"region":"{region}", "instance_id":"{instance_id}"}}'

Both options result in a string that looks like this:

{"region":"us-east-1", "instance_id":"i-1234567890"}

Note that I'm showing you how to use string interpolation to inject variable values into a string. Now you need to do this and inject both region and instance_id into the DashboardBody string. For example:

DashboardBody='{"widgets": [{"type": "metric", "x": 12, "y": 0, "width": 12, "height": 6, "properties": {"metrics": [[ "AWS/EC2", "CPUUtilization", "InstanceId","%s" ]], "view": "timeSeries", "stacked": false, "region":"%s", "stat": "Average", "period": 60, "title": "CPUUtilization" }}]}' % (instance_id, region)

Answer 2

Your json body for 'DashboardBody' should be like this:

    {
       "widgets": [
          {
             "type": "metric",
             "x": 12,
             "y": 0,
             "width": 12,
             "height": 6,
             "properties":{
                "metrics":[
                   [
                      "AWS/EC2",
                      "CPUUtilization",
                      "InstanceId",
                      instance_id
                   ]
                ],
                "view": "timeSeries",
                "stacked": false,
                "region": regions,
                "stat": "Average", 
                "period": 60, 
                "title": "CPUUtilization"

             }
          }
       ]
    }

Also You were passing incorrect value for "region" parameter, it should be regions (as declared in your code) and not region.