# data-alarm-slack

data-alarm-slack

## Setup
* Install [docker](https://docs.docker.com/get-docker/)
* Clone this repository
* Navigate to the lambda you want to work on in `lambda/`

## Running

### Start Container
```
$ docker-compose up --build -d function
```

### Execute Function
Use the HTTP client of your choice. The body of the request is the `event` passed into the function.

```
curl --request POST \
  --url http://localhost:9000/2015-03-31/functions/function/invocations \
  --header 'Content-Type: application/json' \
  --data $(cat tests/sample_event.json)
```

### Load Changes
The `src` directory and `config.py` are mounted into the container via the `docker-compose.yaml` configuration. This means you don't need to re-build the entire container to see changes. **However** the container will need to be restarted. This process should be as quick as restarting uwsgi when making changes to a web application.
```
$ docker-compose restart function
```
:zap: You should add this command to a post-write hook in your preferred editor to automatically restart.

### Deploy to Dev

If you would like to deploy your lambda to the AWS Dev environment before pushing to AWS ECR make sure that the Docker image is built for the proper platform (especially if you are using M1 chip).
So instead of
```shell
$ docker build -t my-lambda .
```
do
```shell
$ docker build -t my-lambda --platform=linux/amd64 .
```

## Linting and Testing

### Run Container
```
$ docker-compose up --build lint-and-test
```

### Set pytest Options
Sometimes you may want to customize how tests run using [pytest options](https://docs.pytest.org/en/stable/usage.html) when doing development locally, only running a subset of tests using `-k` for example. Simply edit `TEST_ARGS` value in `docker-compose.yaml`, **without** quotes, to set the options you need.

:warning: Commited changes will modify how the build pipeline runs tests

### Set pytest-cov Options
By default test coverage is calculated for files in `./src` and displayed in a table after tests run.
* If you want to see a detailed output, edit `COV_REPORT` value in `docker-compose.yaml` to be `html` and visit `http://localhost:8000/`
* If you want to turn off coverage report generation, edit `COV_REPORT` value in `docker-compose.yaml` to be `off`

:warning: Commited changes will modify how the build pipeline runs tests, **do not** commit `COV_REPORT=html`

### Skip Linting
When developing locally, you might not want to worry about linting when working to make tests pass. Simple edit the `SKIP_LINT` value in `docker-compose.yaml` to be `1`.

:warning: Careful not to commit changes unless you **really** want to not run linting on the build pipeline

### Capture Exit Code
Unless the container itself crashes, or is killed, the exit code will be `0`. When the exit code of `lint-and-test.sh` script matters, a pull-request builder for example, run tests with the following flags.
```
$ docker-compose up --exit-code-from lint-and-test --abort-on-container-exit --build lint-and-test
```
### Datadog Configuration

In order to get traces and metrics (in addition to logs) from the [Datadog Lambda Library](https://docs.datadoghq.com/serverless/installation/python/?tab=containerimage), you'll need to have the following environment variables:
    ENVIRONMENT
    DD_LAMBDA_HANDLER (your lambda's original handler, e.g. "src.app.handler")
These can be set via terraform, for example [here](https://github.com/theorchard/terraform-infra/blob/master/qa/lambda-sound-recordings/lambda_sr_add_version.tf#L84-L91).
Notice, the linked example in terraform-infra is utilizing our terraform-lambda module, which does a lot of the setup work under the hood.

### SLACK_HOOK_URL Configuration 
Follow these steps to configure the webhook in Slack:

  1. Navigate to https://<your-team-domain>.slack.com/services/new

  2. Search for and select "Incoming WebHooks".

  3. Choose the default channel where messages will be sent and click "Add Incoming WebHooks Integration".

  4. Copy the webhook URL from the setup instructions and use it in the next section.


Follow these steps to encrypt your Slack hook URL for use in this function:

  1. Create a KMS key - http://docs.aws.amazon.com/kms/latest/developerguide/create-keys.html.

  2. Encrypt the event collector token using the AWS CLI.
     $ aws kms encrypt --key-id alias/<KMS key name> --plaintext "<SLACK_HOOK_URL>"

     Note: You must exclude the protocol from the URL (e.g. "hooks.slack.com/services/abc123").

  3. Copy the base-64 encoded, encrypted key (CiphertextBlob) to the ENCRYPTED_HOOK_URL variable.

  4. Give your function's role permission for the kms:Decrypt action.
     Example:

{
    "Version": "2012-10-17",
    "Statement": [
        {
            "Sid": "Stmt1443036478000",
            "Effect": "Allow",
            "Action": [
                "kms:Decrypt"
            ],
            "Resource": [
                "<your KMS key ARN>"
            ]
        }
    ]
}