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Tracing your own app

Set up lltrace-aws-sdk

Wait for enough activity to be traced

(a quick load-test is good if you're impatient)

Run lltrace

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What can be traced

• S3 putObject and uploadFile
• Invoking other lambdas
• Publishing to SNS topics
• Custom actions (e.g. write to Neo4J)

Sampling

By default only 10% of traced actions actually get logged.

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How it works

SNS and S3 notifications are easy

Lambda activity - not quite so

Solution: monkey-patch aws-sdk 🙈

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What we wanted

To recap:

• 20 lambdas
• 10 SNS topics (more than one subscriber/publisher for some)
• S3 buckets (triggering lambdas)

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AWS API Gateway

GraphQL

Lambda

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config:
  target: "http://localhost:3003"
  phases:
    - duration: 1
      arrivalRate: 1
scenarios:
  - flow:
      - get:
          url: "/"
      - get:

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- post:
    url: "/some/url"
    formData:
      firstName: "Jerry"
      lastName: "Winston"
    headers:
      authorization: "Bearer {{access_token}}"

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//
// Lambda's timeout needs to be >5 seconds, 10 should do
//

var startedAt = new Date();

var interval = setInterval(function () {
    console.log(startedAt, new Date());
}, 1000);

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config:
  target: "http://localhost:8080"
  phases:
    - duration: 60
      arrivalRate: 1
  processor: "./processor.js"
scenarios:
  - name: "Load the options page"
    flow:
      - get:

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{
  "config": {
    "target": "http://localhost",
    "phases": [
      {"duration": 10, "arrivalRate": 20}
    ]
  },
  "scenarios": [
    {
      "flow": [