AWS Cost Explorer Report Generator

Python SAM Lambda module for generating an Excel cost report with graphs, including month on month cost changes. Uses the AWS Cost Explorer API for data.

License Summary

This sample code is made available under a modified MIT license. See the LICENSE file.

AWS Costs

• AWS Lambda Invocation
  • Usually Free
• Amazon SES
  • Usually Free
• Amazon S3
  • Minimal usage
• AWS Cost Explorer API calls
  • $0.01 per API call (about 25 calls per run)

Prerequisites

• awscli
• Configure AWS credentials for target account
  • run aws configure
• Cost Explorer enabled
• Verfied Amazon SES Sender email
• If you verify an email, you can send from/to that address.
• To send to other addresses, you need to move SES out of sandbox mode.

Docker (optional for building the lambda python package with updated https://pypi.python.org/ third-party libraries)

Easy Deploy (us-east-1 only)

If you do not need to modify the code, just deploy the included easy_deploy.yaml using AWS Cloudformation via the console.

Deploying (SAM / Script)

Update the values in deploy.sh for your AWS account details.

Variable	Description
S3_BUCKET	S3 Bucket to use
SES_SEND	Email list to send to (comma separated)
SES_FROM	SES Verified Sender Email
SES_REGION	SES Region
COST_TAGS	List Of Cost Tag Keys (comma separated)
CURRENT_MONTH	true / false for if report does current partial month
DAY_MONTH	When to schedule a run. 6, for the 6th by default
TAG_KEY	Provide tag key e.g. Name
TAG_VALUE_FILTER	Provide tag value to filter e.g. Prod*
LAST_MONTH_ONLY	Specify true if you wish to generate for only last month

And then run sh deploy.sh

Deploy Manually (Lambda Console)

1. Create a lambda function (python 3.8 runtime), and update the code to the contents of src/lambda.py
2. Create a lambda IAM execution role with ce:, ses:, s3:, organizations:ListAccounts
3. Configure the dependency layer: arn:aws:lambda:us-east-1:749981256976:layer:CostExplorerReportLayer:1
4. Update ENV Variables in Lambda console
   • Details in table above.
5. Create a trigger (CloudWatch Event)

Running / Testing

Once the Lambda is created, find it in the AWS Lambda console. You can create ANY test event (as the event content is ignored), and hit the test button for a manual run.

https://docs.aws.amazon.com/lambda/latest/dg/tutorial-scheduled-events-test-function.html

Building the Lambda Layer (Optional, for if you want to build your own AWS Lambda layer for use with the script)

Run build.sh to build a new AWS lambda layer with the required Python libraries. This requires Docker, as it builds the package in an Amazon Linux container.

sh build.sh

Customise the report

Edit the main_handler segment of src/lambda.py

def main_handler(event=None, context=None): 
    costexplorer = CostExplorer(CurrentMonth=False)
    #Default addReport has filter to remove Support / Credits / Refunds / UpfrontRI
    #Overall Billing Reports
    costexplorer.addReport(Name="Total", GroupBy=[],Style='Total',IncSupport=True)
    costexplorer.addReport(Name="TotalChange", GroupBy=[],Style='Change')
    costexplorer.addReport(Name="TotalInclCredits", GroupBy=[],Style='Total',NoCredits=False,IncSupport=True)
    costexplorer.addReport(Name="TotalInclCreditsChange", GroupBy=[],Style='Change',NoCredits=False)
    costexplorer.addReport(Name="Credits", GroupBy=[],Style='Total',CreditsOnly=True)
    costexplorer.addReport(Name="Refunds", GroupBy=[],Style='Total',RefundOnly=True)
    costexplorer.addReport(Name="RIUpfront", GroupBy=[],Style='Total',UpfrontOnly=True)
    #GroupBy Reports
    costexplorer.addReport(Name="Services", GroupBy=[{"Type": "DIMENSION","Key": "SERVICE"}],Style='Total',IncSupport=True)
    costexplorer.addReport(Name="ServicesChange", GroupBy=[{"Type": "DIMENSION","Key": "SERVICE"}],Style='Change')
    costexplorer.addReport(Name="Accounts", GroupBy=[{"Type": "DIMENSION","Key": "LINKED_ACCOUNT"}],Style='Total')
    costexplorer.addReport(Name="AccountsChange", GroupBy=[{"Type": "DIMENSION","Key": "LINKED_ACCOUNT"}],Style='Change')
    costexplorer.addReport(Name="Regions", GroupBy=[{"Type": "DIMENSION","Key": "REGION"}],Style='Total')
    costexplorer.addReport(Name="RegionsChange", GroupBy=[{"Type": "DIMENSION","Key": "REGION"}],Style='Change')
    if os.environ.get('COST_TAGS'): #Support for multiple/different Cost Allocation tags
        for tagkey in os.environ.get('COST_TAGS').split(','):
            tabname = tagkey.replace(":",".") #Remove special chars from Excel tabname
            costexplorer.addReport(Name="{}".format(tabname)[:31], GroupBy=[{"Type": "TAG","Key": tagkey}],Style='Total')
            costexplorer.addReport(Name="Change-{}".format(tabname)[:31], GroupBy=[{"Type": "TAG","Key": tagkey}],Style='Change')
    #RI Reports
    costexplorer.addRiReport(Name="RICoverage")
    costexplorer.addRiReport(Name="RIUtilization")
    costexplorer.addRiReport(Name="RIUtilizationSavings", Savings=True)
    costexplorer.addRiReport(Name="RIRecommendation")
    costexplorer.generateExcel()
    return "Report Generated"