Application Services - V3 Migration Guide

Configuration

The migration of any Application Service's configuration starts with migrating configuration common to all EdgeX services. See the V3 Migration of Common Configuration section for details including the change from TOML format to YAML format for the configuration file. The remainder of this section focuses on configuration specific to Application Services.

Common Configuration Removed

Any configuration that is common to all EdgeX services or all EdgeX Application Services needs to be removed from custom application service's private configuration.

• See Common Service Configuration section for details about configuration that is common to all Edgex services.
• See Application Service Configuration section for details about configuration that is common to all EdgeX Application Services.

MessageBus

The EdgeX MessageBus configuration has been moved out of the Trigger configuration and most values are placed in the common configuration. The only values remaining in the application service's private configuration are:

• Disabled - Used to disable the use of the EdgeX MessageBus when not using metrics and not using edgex-messagebus Trigger type. Value need to be present so that it can be overridden with environment variable.
• Optional.ClientId - Unique name needed for when MQTT or NATS are used as the MessageBus implementation.

MessageBus:
  Disabled: false  # Set to true if not using metrics and not using `edgex-messagebus` Trigger type
  Optional:
    ClientId: "<service-key>"

Trigger

edgex-messagebus changes

As noted above the EdgeX MessageBus configuration has been removed from the Trigger configuration. In addition, the SubscribeTopics and PublishTopic settings have been move to the top level of the Trigger configuration. Most application services can simply use the default trigger configuration from application service common configuration.

Trigger:
  Type: "edgex-messagebus"
  SubscribeTopics: "events/#" # Base topic is prepended to this topic when using edgex-messagebus

# Using default Trigger config from common config

Some application services may need to publish results back to the EdgeX MessageBus. In this case the PublishTopic will remain in the service private configuration.

Trigger:
  # Default value for SubscribeTopics is also set in common config
  PublishTopic: "<my-topic>"  # Base topic is prepended to this topic when using edgex-messagebus

edgex-messagebus Trigger Migration

• If the common Trigger configuration is what your service needs

  1. Remove your Trigger configuration completely

• If your service publishes back to the EdgeX MessageBus

  1. Move your PublishTopic to top level in your Trigger configuration
  2. Remove edgex/ prefix if used
  3. Remove remaining Trigger configuration

• If your service uses filter by topic

  1. Move SubscribeTopics to top level in your Trigger configuration
  2. Remove edgex/ prefix from each topic if used
  3. Replace # between levels with + . See Multi-level topics and wildcards section for more details
  4. Remove remaining Trigger configuration

External MQTT changes

The External MQTT trigger configuration remains under Trigger configuration, but the SubscribeTopics and PublishTopic setting have been moved to the top level of the Trigger configuration.

Trigger:
  Type: "external-mqtt"
  SubscribeTopics: "external-request/#"
  PublishTopic: "" # optional if publishing response back to the the External MQTT Broker
  ExternalMqtt:
    Url: "tcp://broker.hivemq.com:1883" #  fully qualified URL to connect to the MQTT broker
    ClientId: "app-my-service"
    ConnectTimeout: "30s" 
    AutoReconnect: true
    KeepAlive: 10 # Seconds (must be 2 or greater)
    QoS: 0 # Quality of Service 0 (At most once), 1 (At least once) or 2 (Exactly once)
    Retain: true
    SkipCertVerify: false
    SecretName: "mqtt-trigger" 
    AuthMode: "none"

external-mqtt Trigger Migration

1. Move your SubscribeTopics and PublishTopic top level of the Trigger configuration

HTTP Changes

The HTTP trigger configuration has not changed for EdgeX 3.0

Writable Pipeline

See Pipeline Configuration section below for changes to the Writable Pipeline configuration

Custom Application Service

Dependencies

You first need to update the go.mod file to specify go 1.20 and the v3 versions of the App Functions SDK and any EdgeX go-mods directly used by your service.

module <your service>

go 1.20

require (
    github.com/edgexfoundry/app-functions-sdk-go/v3 v3.0.0
    github.com/edgexfoundry/go-mod-core-contracts/v3 v3.0.0
)

Once that is complete then the import statements for these dependencies must be updated to include the /v3 in the path.

import (
    ...

    "github.com/edgexfoundry/app-functions-sdk-go/v3/pkg/interfaces"
    "github.com/edgexfoundry/go-mod-core-contracts/v3/dtos"
)

API Changes

ApplicationService API

The ApplicationService API has the following changes:

1. SetFunctionsPipeline has been removed. Use SetDefaultFunctionsPipeline instead
2. MakeItRun has been renamed to Run
3. MakeItStop has been renamed to Stop
4. GetSecret has been removed. Use SecretProvider().GetSecret
5. StoreSecret has been removed. Use SecretProvider().StoreSecret
6. LoadConfigurablePipeline has been removed. Use LoadConfigurableFunctionPipelines
7. CommandClient Get API's dsPushEvent and dsReturnEvent parameters changed to be type bool

See Application Service API section for completed details on this API, including some new capabilities.

AppFunctionContext API

The AppFunctionContext API has the following changes:

1. Deprecated PushToCore has been removed. Use WrapIntoEvent function and publishing to the EdgeX MessageBus instead. See Trigger.PublishTopic or Publish sections for more details on publishing data back to the EdgeX MessageBus.
2. GetSecret has been removed. Use SecretProvider().GetSecret
3. StoreSecret has been removed. Use SecretProvider().StoreSecret
4. SecretsLastUpdated has been removed. Use SecretProvider().SecretsLastUpdated
5. CommandClient Get API's dsPushEvent and dsReturnEvent parameters changed to be type bool

Pipeline Functions

• AESProtection
  • NewAESProtection signature has changes.
    • secretName parameter renamed tosecretValueKey
    • secretPath parameter renamed to secretName
  • Encrypt pipeline function now require a *AESProtection for the receiver
  • NewAESProtection now returns a *AESProtection
• Compression
  • All Compression pipeline functions now require a *Compression for the receiver
  • NewCompression now returns a *Compression
• Conversion
  • All Conversion pipeline functions now require a *Conversion for the receiver
  • NewConversion now returns a *Conversion
• CoreData- Removed
  • The deprecated PushToCoreData function has been removed. Use WrapIntoEvent function and publishing to the EdgeX MessageBus instead. See Trigger.PublishTopic or Publish sections for more details on publishing data back to the EdgeX MessageBus.
• Encryption - Removed
  • The deprecated EncryptWithAES function has been removed, use AESProtection.Encrypt instead. See AES Protection for more details
• Filter
  • All Filter pipeline functions now requires a *Filter for the receiver
  • NewFilterFor and NewFilterOut now return a *Filter
• HTTPSender
  • NewHTTPSenderWithSecretHeader signature has changed
    • secretName parameter renamed tosecretValueKey
    • secretPath parameter renamed to secretName
• JSONLogic
  • Evaluate pipeline function now requires a *JSONLogic for the receiver
  • NewJSONLogic now returns a *JSONLogic
• MQTTSecretSender
  • MQTTSecretConfig has changed
    • SecretPath field renamed to SecretName
• ResponseData
  • SetResponseData pipeline function now requires a *ResponseData for the receiver
  • NewResponseData now returns a *ResponseData
• Tags
  • Factory function NewGenericTags has been removed and replaced with new version of NewTags which takes map[string]interface{} for the tags parameter.
  • NewTags now returns a *Tags

App Service Configurable

Profiles

• PushToCore profile has been removed. Use WrapIntoEvent function and publishing to the EdgeX MessageBus instead. See Trigger.PublishTopic or Publish sections for more details on publishing data back to the EdgeX MessageBus.

Custom Profiles

Custom profiles for App Service Configurable must be migrated in a similar fashion to the configuration for custom application services. All configuration that is common to all EdgeX services or all EdgeX Application Services needs to be removed from custom profiles. See Common Service Configuration section for details about configuration that is common to all Edgex services. See Application Service Configuration section for details about configuration that is common to all EdgeX Application Services. Use the App Service Configurable provided profiles as examples of what configuration is left after removing the common configuration.

Pipeline Configuration

• Writable.Pipeline.TargetType has change from a bool to a string with valid values or raw, event or metric
• Topic wild cards have changed to conform 100% with MQTT scheme. The # between level has be replaced with + . See Multi-level topics and wildcards for more details.
• HTTPExport function configuration
  • Parameter SecretName renamed to be SecretValueKey
  • Parameter SecretPath renamed to be SecretName
• Encrypt function configuration
  • Parameter SecretName renamed to be SecretValueKey
  • Parameter SecretPath renamed to be SecretName

Environment Variable Overrides

Environment variable overrides must be adjusted appropriately for the above changes. Remove any overrides that apply to common configuration.