Lambda@Edge CloudFront Debugging Sample Records

context.json

{
  "callbackWaitsForEmptyEventLoop":true,
  "logGroupName":"/aws/lambda/us-east-1.DebugEvent",
  "logStreamName":"2018/10/16/zzz",
  "functionName":"us-east-1.DebugEvent",
  "memoryLimitInMB":"128",
  "functionVersion":"2",
  "invokeid":"ad19fdb1-zzz-zzz-zzz-zzz",
  "awsRequestId":"ad19fdb1-zzz-zzz-zzz-zzz",
  "invokedFunctionArn":"arn:aws:lambda:us-east-1:zzz:function:us-east-1.DebugEvent:2"
}

DebugEvent.js

'use strict';

/**
  * Lambda@Edge to log CloudFront event and context.
  * Note: this runs in Lambda@Edge which means it runs in a variety
  * of regions, the region closest to the browser making the request.
  * So be sure and check other regions if you don't see the logs in
  * CloudWatch in the region you normally use.
  * 
  * https://medium.com/@jbesw/postcards-from-lambda-the-edge-11a43f215dc1
  *
  */
exports.handler = (event, context, callback) => {

  const eventType = event.Records[0].cf.config.eventType;
  
  // Log JSON of the event and context if available to console which
  // will end up in CloudWatch
  console.log('DebugEvent ' + eventType 
    + ' -- ' + JSON.stringify(event)
    + ' -- context -- ' + JSON.stringify(context)
  );
    
  const responseEvent = eventType.indexOf('-response') > 0;
  
  // Response back to CloudFront and let the HTTP request continue  
  callback(null, 
    (responseEvent ? 
      event.Records[0].cf.response : event.Records[0].cf.request));
}; 

origin-request-event.json

{
  "Records":[
    {
      "cf":{
        "config":{
          "distributionDomainName":"d1zzzlmt.cloudfront.net",
          "distributionId":"E1zzzGZ",
          "eventType":"origin-request"
        },
        "request":{
          "clientIp":"2607:zzz:1812:zzz:c06e:zzz:99e7:da29",
          "headers":{
            "user-agent":[
              {
                "key":"User-Agent",
                "value":"Amazon CloudFront"
              }
            ],
            "via":[
              {
                "key":"Via",
                "value":"1.1 7fa8abd93azzzbdcbc31.cloudfront.net (CloudFront)"
              }
            ],
            "accept-encoding":[
              {
                "key":"Accept-Encoding",
                "value":"gzip"
              }
            ],
            "x-forwarded-for":[
              {
                "key":"X-Forwarded-For",
                "value":"2607:zzz:zzz:zzz:c06e:38cc:99e7:da29"
              }
            ],
            "host":[
              {
                "key":"Host",
                "value":"pzzze.s3.amazonaws.com"
              }
            ]
          },
          "method":"GET",
          "origin":{
            "s3":{
              "authMethod":"origin-access-identity",
              "customHeaders":{

              },
              "domainName":"pzzze.s3.amazonaws.com",
              "path":"",
              "region":"us-east-1"
            }
          },
          "querystring":"",
          "uri":"/mycalendar.ics"
        }
      }
    }
  ]
}

origin-response-event.json

{
  "Records":[
    {
      "cf":{
        "config":{
          "distributionDomainName":"d1zzzlmt.cloudfront.net",
          "distributionId":"E1zzz8GZ",
          "eventType":"origin-response"
        },
        "request":{
          "clientIp":"6.2.1.7",
          "headers":{
            "user-agent":[
              {
                "key":"User-Agent",
                "value":"Amazon CloudFront"
              }
            ],
            "via":[
              {
                "key":"Via",
                "value":"1.1 caf2zzzb43da60.cloudfront.net (CloudFront)"
              }
            ],
            "accept-encoding":[
              {
                "key":"Accept-Encoding",
                "value":"gzip"
              }
            ],
            "host":[
              {
                "key":"Host",
                "value":"pzzze.s3.amazonaws.com"
              }
            ],
            "x-forwarded-for":[
              {
                "key":"X-Forwarded-For",
                "value":"6.2.1.7"
              }
            ]
          },
          "method":"GET",
          "origin":{
            "s3":{
              "authMethod":"origin-access-identity",
              "customHeaders":{

              },
              "domainName":"pzzze.s3.amazonaws.com",
              "path":"",
              "region":"us-east-1"
            }
          },
          "querystring":"",
          "uri":"/mycalendar.ics"
        },
        "response":{
          "headers":{
            "x-amz-request-id":[
              {
                "key":"x-amz-request-id",
                "value":"B6DzzzD48"
              }
            ],
            "x-amz-id-2":[
              {
                "key":"x-amz-id-2",
                "value":"KzMQLDzzzj93XRhGYMchr5shuiYsM9EJu1wLS0+IM="
              }
            ],
            "date":[
              {
                "key":"Date",
                "value":"Tue, 16 Oct 2018 22:05:05 GMT"
              }
            ],
            "server":[
              {
                "key":"Server",
                "value":"AmazonS3"
              }
            ],
            "content-type":[
              {
                "key":"Content-Type",
                "value":"application/xml"
              }
            ],
            "transfer-encoding":[
              {
                "key":"Transfer-Encoding",
                "value":"chunked"
              }
            ]
          },
          "status":"403",
          "statusDescription":"Forbidden"
        }
      }
    }
  ]
}

viewer-request-event.json

{
  "Records":[
    {
      "cf":{
        "config":{
          "distributionDomainName":"d1lzzzlmt.cloudfront.net",
          "distributionId":"zzz",
          "eventType":"viewer-request",
          "requestId":"zsDwxGzzz-DG-zzz-s0uwyQ=="
        },
        "request":{
          "clientIp":"6.2.1.7",
          "headers":{
            "host":[
              {
                "key":"Host",
                "value":"example.com"
              }
            ],
            "user-agent":[
              {
                "key":"User-Agent",
                "value":"iOS/12.0.1 (16A404) dataaccessd/1.0"
              }
            ],
            "accept":[
              {
                "key":"accept",
                "value":"text/calendar"
              }
            ],
            "accept-language":[
              {
                "key":"accept-language",
                "value":"en-us"
              }
            ],
            "accept-encoding":[
              {
                "key":"accept-encoding",
                "value":"br, gzip, deflate"
              }
            ]
          },
          "method":"GET",
          "querystring":"",
          "uri":"/mycalendar.ics"
        }
      }
    }
  ]
}

viewer-response-event.json

{
  "Records":[
    {
      "cf":{
        "config":{
          "distributionDomainName":"d1lzzzlmt.cloudfront.net",
          "distributionId":"zzz",
          "eventType":"viewer-response",
          "requestId":"ohSdzzzmp5a-zzz-zzz=="
        },
        "request":{
          "clientIp":"6.2.1.7",
          "headers":{
            "host":[
              {
                "key":"Host",
                "value":"example.com"
              }
            ],
            "user-agent":[
              {
                "key":"User-Agent",
                "value":"Mozilla/5.0 (Macintosh; Intel Mac OS X 10_14) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/12.0 Safari/605.1.15"
              }
            ],
            "accept":[
              {
                "key":"accept",
                "value":"text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8"
              }
            ],
            "accept-language":[
              {
                "key":"accept-language",
                "value":"en-us"
              }
            ],
            "accept-encoding":[
              {
                "key":"accept-encoding",
                "value":"br, gzip, deflate"
              }
            ],
            "dnt":[
              {
                "key":"dnt",
                "value":"1"
              }
            ]
          },
          "method":"GET",
          "querystring":"",
          "uri":"/"
        },
        "response":{
          "headers":{
            "x-amz-id-2":[
              {
                "key":"x-amz-id-2",
                "value":"Lzhzzzzz6Y7oo="
              }
            ],
            "x-amz-request-id":[
              {
                "key":"x-amz-request-id",
                "value":"8zzzzz742"
              }
            ],
            "date":[
              {
                "key":"Date",
                "value":"Tue, 16 Oct 2018 18:13:35 GMT"
              }
            ],
            "last-modified":[
              {
                "key":"Last-Modified",
                "value":"Mon, 15 Oct 2018 23:54:20 GMT"
              }
            ],
            "etag":[
              {
                "key":"ETag",
                "value":"\"e7zzzzzz8702e33\""
              }
            ],
            "x-amz-server-side-encryption":[
              {
                "key":"x-amz-server-side-encryption",
                "value":"AES256"
              }
            ],
            "cache-control":[
              {
                "key":"Cache-Control",
                "value":"max-age=86400,public"
              }
            ],
            "server":[
              {
                "key":"Server",
                "value":"AmazonS3"
              }
            ],
            "strict-transport-security":[
              {
                "key":"Strict-Transport-Security",
                "value":"max-age=50000;"
              }
            ],
            "x-content-type-options":[
              {
                "key":"X-Content-Type-Options",
                "value":"nosniff"
              }
            ],
            "x-frame-options":[
              {
                "key":"X-Frame-Options",
                "value":"DENY"
              }
            ],
            "x-xss-protection":[
              {
                "key":"X-XSS-Protection",
                "value":"1; mode=block; report=https://example.report-uri.com/r/d/csp/enforce"
              }
            ],
            "content-security-policy":[
              {
                "key":"Content-Security-Policy",
                "value":"upgrade-insecure-requests; default-src 'none'; font-src fonts.gstatic.com use.fontawesome.com; style-src 'self' cdnjs.cloudflare.com fonts.googleapis.com use.fontawesome.com; img-src 'self' example.com; script-src 'self' cdnjs.cloudflare.com; connect-src app.com example.com; report-uri https://example.report-uri.com/r/d/csp/enforce"
              }
            ],
            "referrer-policy":[
              {
                "key":"Referrer-Policy",
                "value":"same-origin"
              }
            ],
            "content-encoding":[
              {
                "key":"Content-Encoding",
                "value":"gzip"
              }
            ],
            "vary":[
              {
                "key":"Vary",
                "value":"Accept-Encoding"
              }
            ],
            "age":[
              {
                "key":"Age",
                "value":"9251"
              }
            ],
            "content-type":[
              {
                "key":"Content-Type",
                "value":"text/html"
              }
            ],
            "transfer-encoding":[
              {
                "key":"Transfer-Encoding",
                "value":"chunked"
              }
            ]
          },
          "status":"200",
          "statusDescription":"OK"
        }
      }
    }
  ]
}

Sample context (which is basically the same for all event types), and event object for each event type. Note these examples are NOT all from the same single HTTP request. But regardless they give you an idea of what data to expect in the event object passed to your Lambda method.

As mentioned here