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https://github.com/base2services/aws-lambda-http-check
Lambda function to check http endpoint wrapped in serverless project
https://github.com/base2services/aws-lambda-http-check
aws aws-cloudwatch cloudwatch http-endpoint-check lambda monitoring-tool python serverless
Last synced: 3 months ago
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Lambda function to check http endpoint wrapped in serverless project
- Host: GitHub
- URL: https://github.com/base2services/aws-lambda-http-check
- Owner: base2Services
- License: mit
- Created: 2017-10-05T05:27:01.000Z (over 7 years ago)
- Default Branch: master
- Last Pushed: 2023-11-23T23:37:35.000Z (about 1 year ago)
- Last Synced: 2023-11-24T00:27:09.345Z (about 1 year ago)
- Topics: aws, aws-cloudwatch, cloudwatch, http-endpoint-check, lambda, monitoring-tool, python, serverless
- Language: Python
- Size: 29.3 KB
- Stars: 32
- Watchers: 11
- Forks: 16
- Open Issues: 2
-
Metadata Files:
- Readme: README.md
- License: LICENSE
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README
# Lambda http check
Lambda function to check specific http endpoint, and report on it's availability.
Optionally, it can record metrics to CloudWatch.
## Inputs
All inputs are either defined as environment variables or as part of event data. Event data
will take priority over environment variables
`ENDPOINT` - url to be checked
`METHOD` - http method to use, defaults to `GET`
`PAYLOAD` - http payload, if `POST` or `PUT` used as method
`TIMEOUT` - timeout to use for http requests, defaults to 120s
`HEADERS` - list of _percentage sign (%)_ separated headers to send to target server, defaults to empty list.
`USER_AGENT` - If specified, will be added to the HEADERS. An example is: `Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:15.0) Gecko/20100101 Base2/Lambda`
`REPORT_RESPONSE_BODY` - set to 1 if you wish to report on response body, 0
otherwise, 0 otherwise, defaults to 0
`REPORT_AS_CW_METRICS` - set to 1 if you wish to store reported data as CW
custom metrics, 0 otherwise, defaults to 1
`CW_METRICS_NAMESPACE` - if CW custom metrics are being reported, this will determine
their namespace, defaults to 'HttpCheck'
`BODY_REGEX_MATCH` - if CW custom metrics are being reported, this will enable `ResponseBodyRegexMatch`
metric to be published as well, with value determined by success of matching response body against
regular expression contained within this option
`STATUS_CODE_MATCH` - report whether http status code is equal to given status code or not. If this option
is not present, it won't be reported upon. Defaults to empty
`FAIL_ON_STATUS_CODE_MISMATCH` - if checking for status code match treat mismatch as failure, ie report `Available: 0`
## Outputs
By default, following properties will be rendered in output Json
`Reason` - Reason
`Available` - 0 or 1
`TimeTaken` - Time in ms it took to get response from remote server. Default timeout
is 2 minutes for http requests.
`StatusCode` - Http Status Code
`ResponseBody` - Optional, by default this won't be reported
`ResponseBodyRegexMatch` - Optional, if `BODY_REGEX_MATCH` option is provided
`StatusCodeMatch` - Optional, if `STATUS_CODE_MATCH` options is provided
## Dependencies
Lambda function is having no external dependencies by design, so no additional packaging steps are required
for deploying it, such as doing `pip install [libname]`
## CloudWatch Metrics
In order to get some metrics which you can alert on, `REPORT_AS_CW_METRICS` and `CW_METRICS_NAMESPACE` environment
variables are used. Following metrics will be reported
- `Available` - 0 or 1, whether response was received in timely manner, indicating problems with network, DNS lookup or
server timeout
- `TimeTaken` - Time taken to fetch response, reported in milliseconds
- `StatusCode` - HTTP Status code received from server
- `ResponseBodyRegexMatch` - **optional** this will report 1 or 0 if `BODY_REGEX_MATCH` option is specified. 1 is reported
if response body matches regex provided, or 0 otherwise.
- `StatusCodeMatch` - **optional*& this will report 1 or 0 if `STATUS_CODE_MATCH` options is specified. 1 is reported
if response status code matches code provided, or 0 otherwise
## Deployment
You can either deploy Lambda manually, or through [AWS SAM CLI](https://docs.aws.amazon.com/serverless-application-model/latest/developerguide/what-is-sam.html).
If the SAM CLI is being chosen as method of deployments use command below, while
making sure that you have [setup access](https://docs.aws.amazon.com/serverless-application-model/latest/developerguide/serverless-getting-started-set-up-credentials.html) to your AWS account.
build the lambda
```sh
sam build
```
deploy the template
```sh
sam deploy --guided
```
If you are setting up your Lambda function by hand, make sure it has proper IAM
permissions to push Cloud Watch metrics data, and to write to CloudWatch logs
## Testing
To test function locally with simple Google url (default), run following
```
sam local invoke Check
```
Optionally, for complicated example take a look at `test/ipify.json` file
```sh
sam local invoke Check --event test/ipify.json
```
## Debugging
If you wish to see debug output for http request, set `HTTP_DEBUG` environment
variable to '1'. This can't be controlled through event payload.
## Schedule execution
Pull requests are welcome to serverless project to deploy CloudWatch rules in order
to schedule execution of Http Checking Lambda function.