How to: Use the Multi-App Run template file

Unpack the Multi-App Run template file and its properties

Note

Multi-App Run is currently a preview feature only supported in Linux/MacOS.

The Multi-App Run template file is a YAML file that you can use to run multiple applications at once. In this guide, you’ll learn how to:

  • Use the multi-app template
  • View started applications
  • Stop the multi-app template
  • Stucture the multi-app template file

Use the multi-app template

You can use the multi-app template file in one of the following two ways:

Execute by providing a directory path

When you provide a directory path, the CLI will try to locate the Multi-App Run template file, named dapr.yaml by default in the directory. If the file is not found, the CLI will return an error.

Execute the following CLI command to read the Multi-App Run template file, named dapr.yaml by default:

  1. # the template file needs to be called `dapr.yaml` by default if a directory path is given
  2. dapr run -f <dir_path>

Execute by providing a file path

If the Multi-App Run template file is named something other than dapr.yaml, then you can provide the relative or absolute file path to the command:

  1. dapr run -f ./path/to/<your-preferred-file-name>.yaml

View the started applications

Once the multi-app template is running, you can view the started applications with the following command:

  1. dapr list

Stop the multi-app template

Stop the multi-app run template anytime with either of the following commands:

  1. # the template file needs to be called `dapr.yaml` by default if a directory path is given
  2. dapr stop -f

or:

  1. dapr stop -f ./path/to/<your-preferred-file-name>.yaml

Template file structure

The Multi-App Run template file can include the following properties. Below is an example template showing two applications that are configured with some of the properties.

  1. version: 1
  2. common: # optional section for variables shared across apps
  3. resourcesPath: ./app/components # any dapr resources to be shared across apps
  4. env: # any environment variable shared across apps
  5. DEBUG: true
  6. apps:
  7. - appID: webapp # optional
  8. appDirPath: .dapr/webapp/ # REQUIRED
  9. resourcesPath: .dapr/resources # (optional) can be default by convention
  10. configFilePath: .dapr/config.yaml # (optional) can be default by convention too, ignore if file is not found.
  11. appProtocol: http
  12. appPort: 8080
  13. appHealthCheckPath: "/healthz"
  14. command: ["python3" "app.py"]
  15. - appID: backend # optional
  16. appDirPath: .dapr/backend/ # REQUIRED
  17. appProtocol: grpc
  18. appPort: 3000
  19. unixDomainSocket: "/tmp/test-socket"
  20. env:
  21. - DEBUG: false
  22. command: ["./backend"]

Important

The following rules apply for all the paths present in the template file:

  • If the path is absolute, it is used as is.
  • All relative paths under comman section should be provided relative to the template file path.
  • appDirPath under apps section should be provided relative to the template file path.
  • All relative paths under app section should be provided relative to the appDirPath.

Template properties

The properties for the Multi-App Run template align with the dapr run CLI flags, listed in the CLI reference documentation.

PropertiesRequiredDetailsExample
appDirPathYPath to the your application code./webapp/, ./backend/
appIDNApplication’s app ID. If not provided, will be derived from appDirPathwebapp, backend
resourcesPathNPath to your Dapr resources. Can be default by convention; ignore if directory isn’t found./app/components, ./webapp/components
configFilePathNPath to your application’s configuration file./webapp/config.yaml
appProtocolNThe protocol Dapr uses to talk to the application.http, grpc
appPortNThe port your application is listening on8080, 3000
daprHTTPPortNDapr HTTP port
daprGRPCPortNDapr GRPC port
daprInternalGRPCPortNgRPC port for the Dapr Internal API to listen on; used when parsing the value from a local DNS component
metricsPortNThe port that Dapr sends its metrics information to
unixDomainSocketNPath to a unix domain socket dir mount. If specified, communication with the Dapr sidecar uses unix domain sockets for lower latency and greater throughput when compared to using TCP ports. Not available on Windows./tmp/test-socket
profilePortNThe port for the profile server to listen on
enableProfilingNEnable profiling via an HTTP endpoint
apiListenAddressesNDapr API listen addresses
logLevelNThe log verbosity.
appMaxConcurrencyNThe concurrency level of the application; default is unlimited
placementHostAddressN
appSSLNEnable https when Dapr invokes the application
daprHTTPMaxRequestSizeNMax size of the request body in MB.
daprHTTPReadBufferSizeNMax size of the HTTP read buffer in KB. This also limits the maximum size of HTTP headers. The default 4 KB
enableAppHealthCheckNEnable the app health check on the applicationtrue, false
appHealthCheckPathNPath to the health check file/healthz
appHealthProbeIntervalNInterval to probe for the health of the app in seconds
appHealthProbeTimeoutNTimeout for app health probes in milliseconds
appHealthThresholdNNumber of consecutive failures for the app to be considered unhealthy
enableApiLoggingNEnable the logging of all API calls from application to Dapr
runtimePathNDapr runtime install path
envNMap to environment variable; environment variables applied per application will overwrite environment variables shared across applicationsDEBUG, DAPR_HOST_ADD

Next steps

Watch this video for an overview on Multi-App Run:

Last modified February 21, 2023: Fix template reference (#3194) (aef5ea3a)