Zero Overhead with Asynchronous Monitoring

Using Thundra, you can monitor and troubleshoot your serverless-centric system and get insights about the whole architecture. Thundra allows you to instrument your application with no code change. You can send these monitoring data to have these insights in two ways:

• Synchronous monitoring

• Asynchronous monitoring

To send data synchronously to Thundra, an HTTP call to Thundra's collector is made by your Lambda function before an invocation ends. This method is quite easy, but also risky. Should an HTTP call fail, latency could occur and affect your Lambda function's performance. In addition, making an HTTP call will add a duration overhead to the execution time of your Lambda function.

By contrast, asynchronous monitoring requires zero overhead and trace, metric, and log data is structured in JSON format and then written to CloudWatch after data is gathered by Thundra's AWS integration in your account. This means that while observability data becomes visible in your Thundra console at a slower rate than through synchronous monitoring (depending on when it appears in CloudWatch), you're also getting rid of communication overhead, which can go up to 100ms when data is too large.

Configuring asynchronous monitoring is quite simple. Just set the following environment variable to true in your Lambda function and make sure that you're using Thundra's AWS integration:

thundra_agent_lambda_report_cloudwatch_enable

If you aren't using AWS integration, you'll need to install the following Lambda function:

thundra-lambda-adapters-cw.

There are three ways of installing thundra_lambda-adapters_cw to your AWS account:

• ​Manual Setup​

• ​Using Serverless Framework​

• ​Using Deployer Tool​

Manual Setup of Async

1. Setup “thundra-lambda-adapters-cw”

Thundra provides an AWS CloudFormation template to set up the thundra-lambda-adapters-cw Lambda function with the required configurations, permissions, and roles on the user’s end.

• Access CloudFormation on AWS console.

• Click Create Stack

• Select Specify an Amazon S3 template URL and set to https://s3-us-west-2.amazonaws.com/thundra-dist/thundra-lambda-adapters-cw-cloudformation-template.yaml and click Next

• Enter the stack name, such as thundra-lambda-adapters-cw-stack, configure memory size and timeout parameters if needed, and then click “Next.”

• No need to add extra options, so click Next.

• Select I acknowledge that AWS CloudFormation might create IAM resources with custom names. under Capabilities section and click Create.

• Stack creation will begin. Wait until the creation process ends.

2. Subscribe to Lambda functions to be monitored

Go to the thundra-lambda-adapters-cw function in the AWS Lambda console. For each Lambda function that needs to be monitored:

• Add CloudWatch Logs trigger

​

• Configure trigger

  • Log Group: Name of the log group of the Lambda function to be monitored. Log group is in the /aws/lambda/<function-name> format.

  • Filter Name: Enter the desired name of the filter

  • Filter Pattern: Pattern to filter AWS CloudWatch logs to accept only formatted monitor data. It must be {$.type = Invocation || $.type = Trace || $.type = Span || $.type = Metric || $.type = Log || $.type = Composite} and click Add

• Then click Save to apply the changes.

Serverless Framework

You will need to install our custom serverless plugin. However, prior to installation, please remember that:

To begin, go to your service’s directory and then:

• Install the plugin by npm install --save serverless-plugin-thundra-lambda-adapters-cw

• Import the plugin in your serverless.yml

...
​
plugins: 
  - serverless-plugin-thundra-lambda-adapters-cw
  …
​
...

• Enable your lambda to publish on CloudWatch

functions: 
    my-function: 
        ...
        environment:
            ...
            thundra_agent_lambda_report_cloudwatch_enable: true
            ...
        ...
... 

• Set the API key with the thundra_apiKey environment variable, as explained here: https://github.com/thundra-io/serverless-plugin-thundra-lambda-adapters-cw/blob/master/README.md#usage​

functions: 
    my-function: 
        ...
        environment:
            ...
            thundra_apiKey: <my-awesome-api-key> 
            ...
        ... 
    ...

• Alternatively, you can configure the thundra-lambda-adapters-cw Lambda function, as explained here: https://github.com/thundra-io/serverless-plugin-thundra-lambda-adapters-cw/blob/master/README.md#configuration​

custom: 
    ... 
    thundraAdapterFunctionMemorySize: 1536
    thundraAdapterFunctionTimeout: 300 
    ...

• By default, all functions are monitored over AWS CloudWatch. If you want to exclude specific functions, you need to mark them by setting the thundraIgnored flag to true, as explained here: https://github.com/thundra-io/serverless-plugin-thundra-lambda-adapters-cw/blob/master/README.md#usage​

functions: 
    my-function: 
        ... 
        thundraIgnored: true 
        ... 
    ...

• See the following page for more details: https://github.com/thundra-io/serverless-plugin-thundra-lambda-adapters-cw​

  Note: If you get an error like this

...
​
Serverless: Operation failed!
 
  Serverless Error 
  ---------------------------------------
 
  An error occurred: ...LogGroup - /aws/lambda/... already exists.
​
...

You should skip the log group creation process for the mentioned function or for all functions. By default, this plugin creates log groups of monitored functions to subscribe them to Thundra. But if the log group was already created without this plugin (by invocation or manually), log group creation should be skipped. If you don’t skip the log group creation, you will get the “log group already exists” error shown above.

• To skip log group creation for a specific function, you can set the thundraSkipLogGroupCreation flag individually.

functions: 
    my-function: 
        ... 
        thundraSkipLogGroupCreation: true 
        ... 
    ...

• To skip log group creation for all monitored functions, you can set the thundraSkipAllLogGroupCreations property globally.

custom: 
    ... 
    thundraSkipAllLogGroupCreations: true 
    ...

Deployer Tool

Download the tool from https://s3-us-west-2.amazonaws.com/thundra-dist/thundra-lambda-adapters-cw-deployer.jar

This tool has the following usage format:

java -jar thundra-lambda-adapters-cw-deployer.jar 
    -mode=(adapter|subscription|full|export) 
    -region=<region> 
    [-profile=<profile>] 
    [-memory=<memorySize>] 
    [-timeout=<timeout>]  
    [(-functionNames=func1,func2,...) | (-functionNamesFile=functionNamesFile.txt)]

• mode: Specifies the mode of the deployer tool. This property is mandatory and can be one of the following values:

  • adapter: Deploys and sets up the thundra-lambda-adapters-cw Lambda function.

  • subscription: Subscribes the thundra-lambda-adapters-cw Lambda function to the log groups of Lambda functions needing to be monitored.

  • full: Executes both the adapter and subscription modes sequentially.

  • export: Executes both the adapter and subscription modes sequentially.

  • without: Performs actual deployment but just exports generated AWS CloudFormation template files (thundra-lambda-adapters-cw-cloudformation-template.yaml and monitored-function-resource-def-cloudformation-template.yaml) to the directory where you run the deployer tool.

• region: Specifies the AWS region to deploy. This property is mandatory.

• profile: Specifies the AWS profile defined in the ~/.aws/credentials. This property is optional.

• memory: Specifies the memory size of the thundra-lambda-adapters-cw Lambda function. This property is optional, and the default value is 512 MB.

• timeout: Specifies the timeout value of the thundra-lambda-adapters-cw Lambda function. This property is optional, and the default value is 300 seconds (5 minutes).

• functionNames: Specifies the names of the functions to be subscribed for monitoring. Multiple function names can be separated by comma (,) without a space. This property is mandatory if the mode is either subscription or full, and if the functionNamesFile property is not specified.

• functionNamesFile: Specifies the path of the file containing the names of the functions to be subscribed for monitoring. Multiple function names can be separated by a comma (,). This property is mandatory if the mode is either subscription or full, and if the functionNames property is not specified.

For example:

• Deploy thundra-lambda-adapters-cw into region us-west-2: java -jar thundra-lambda-adapters-cw-deployer.jar -mode=adapter -region=us-west-2

• Subscribe thundra-lambda-adapters-cw to my-func-1 and my-func-2 at region us-west-2: java -jar thundra-lambda-adapters-cw-deployer.jar -mode=subscription -region=us-west-2 functionNames=my-func-1,my-func-2

• Do the examples above at one step: java -jar thundra-lambda-adapters-cw-deployer.jar -mode=full -region=us-west-2 functionNames=my-func-1,my-func-2

1.Setup “thundra-lambda-adapters-cw”

• Run the deployer tool with the adapter mode by -mode=adapter argument, as explained above.

• Wait until the application terminates.

2.Subscribe to Lambda functions to be monitored

• Run the deployer tool with the subscription mode by -mode=subscription argument, as explained above.

• Wait until the application terminates.

3.Full setup

• Run the deployer tool with the full mode by -mode=full argument, as explained above.

  Wait until the application terminates.

  ​