docs: document the lambda builder

docs/deployment/builders/builder-management.md

@@ -17,6 +17,7 @@ Dokku supports the following built-in builders:
 
 - `builder-dockerfile`: Builds apps using a `Dockerfile` via `docker build`. See the [dockerfile builder documentation](/docs/deployment/builders/dockerfiles.md) for more information on how this builder functions.
 - `builder-herokuish`: Builds apps with Heroku's v2a Buildpack specification via `gliderlabs/herokuish`. See the [herokuish builder documentation](/docs/deployment/builders/herokuish-buildpacks.md) for more information on how this builder functions.
+- `builder-lambda`: Builds AWS Lambda functions in an environment simulating AWS Lambda runtimes via [lambda-builder](https://github.com/dokku/lambda-builder). See the [lambda builder documentation](/docs/deployment/builders/lambda.md) for more information on how this builder functions.
 - `builder-null`: Does nothing during the build phase. See the [null builder documentation](/docs/deployment/builders/null.md) for more information on how this builder functions.
 - `builder-pack`: Builds apps with Cloud Native Buildpacks via the `pack-cli`  tool. See the [cloud native buildpacks builder documentation](/docs/deployment/builders/cloud-native-buildpacks.md) for more information on how this builder functions.
 

docs/deployment/builders/lambda.md

@@ -0,0 +1,107 @@
+# Lambda Builder
+
+> New as of 0.28.0
+
+The `lambda` builder builds AWS Lambda functions in an environment simulating AWS Lambda runtimes via [lambda-builder](https://github.com/dokku/lambda-builder). Apps built via this builder can run natively in Dokku and may also have their artifacts scheduled to Lambda via an appropriate scheduler.
+
+## Usage
+
+### Detection
+
+This builder will be auto-detected in the following case:
+
+- A `lambda.yml` exists in the root of the app repository.
+
+The builder may also be selected via the `builder:set` command
+
+```shell
+dokku builder:set node-js-app selected lambda
+```
+
+### Supported languages
+
+The `lambda` builder plugin supports the following AWS runtime languages on Amazon Linux 2:
+
+- dotnet
+- go (builder is based on AL1)
+- nodejs
+- python
+- ruby
+
+See the [lambda-builder](https://github.com/dokku/lambda-builder#how-does-it-work) documentation for more information on how specific languages are detected.
+
+### Customizing the build environment
+
+The `lambda` builder plugin delegates all build logic to [lambda-builder](https://github.com/dokku/lambda-builder), including language detection and build/runtime environment specification. The lambda-builder tool supports a `lambda.yml` file format for customizing how apps are built. Please see the readme for lambda-builder for more information on different options.
+
+### Changing the `lambda.yml` location
+
+When deploying a monorepo, it may be desirable to specify the specific path of the `lambda.yml` file to use for a given app. This can be done via the `builder-lambda:set` command. If a value is specified and that file does not exist in the app's build directory, then the build will fail.
+
+```shell
+dokku builder-lambda:set node-js-app lambdayml-path lambda2.yml
+```
+
+The default value may be set by passing an empty value for the option:
+
+```shell
+dokku builder-lambda:set node-js-app lambdayml-path
+```
+
+The `lambdayml-path` property can also be set globally. The global default is `lambda.yml`, and the global value is used when no app-specific value is set.
+
+```shell
+dokku builder-lambda:set --global lambdayml-path lambda2.yml
+```
+
+The default value may be set by passing an empty value for the option.
+
+```shell
+dokku builder-lambda:set --global lambdayml-path
+```
+
+### Displaying builder-lambda reports for an app
+
+You can get a report about the app's storage status using the `builder-lambda:report` command:
+
+```shell
+dokku builder-lambda-json:report
+```
+
+```
+=====> node-js-app builder-lambda information
+       Builder-lambda computed lambdayml path: lambda2.yml
+       Builder-lambda global lambdayml path:   lambda.yml
+       Builder-lambda lambdayml path:          lambda2.yml
+=====> python-sample builder-lambda information
+       Builder-lambda computed lambdayml path: lambda.yml
+       Builder-lambda global lambdayml path:   lambda.yml
+       Builder-lambda lambdayml path:
+=====> ruby-sample builder-lambda information
+       Builder-lambda computed lambdayml path: lambda.yml
+       Builder-lambda global lambdayml path:   lambda.yml
+       Builder-lambda lambdayml path:
+```
+
+You can run the command for a specific app also.
+
+```shell
+dokku builder-lambda:report node-js-app
+```
+
+```
+=====> node-js-app builder-lambda information
+       Builder-lambda computed lambdayml path: lambda2.yml
+       Builder-lambda global lambdayml path:   lambda.yml
+       Builder-lambda lambdayml path:          lambda2.yml
+```
+
+You can pass flags which will output only the value of the specific information you want. For example:
+
+```shell
+dokku builder-lambda:report node-js-app --builder-lambda-lambdayml-path
+```
+
+```
+Dockerfile2
+```

docs/template.html

@@ -147,6 +147,7 @@
             <a href="/{{NAME}}/deployment/builders/cloud-native-buildpacks/" class="list-group-item">Cloud Native Buildpacks</a>
             <a href="/{{NAME}}/deployment/builders/herokuish-buildpacks/" class="list-group-item">Herokuish Buildpacks</a>
             <a href="/{{NAME}}/deployment/builders/dockerfiles/" class="list-group-item">Dockerfile Deployment</a>
+            <a href="/{{NAME}}/deployment/builders/lambda/" class="list-group-item">Lambda Builder</a>
             <a href="/{{NAME}}/deployment/builders/null/" class="list-group-item">Null Builder</a>
 
             <a href="#" class="list-group-item disabled">Deployment Methods</a>