HashiCorp Consul name resolution provider spec

HashiCorp Consul name resolution provider spec

Detailed information on the HashiCorp Consul name resolution component

Configuration format

Hashicorp Consul is setup within the Dapr Configuration.

Within the config, add a nameResolution spec and set the component field to "consul".

If you are using the Dapr sidecar to register your service to Consul then you will need the following configuration:

apiVersion: dapr.io/v1alpha1
kind: Configuration
metadata:
  name: appconfig
spec:
  nameResolution:
    component: "consul"
    configuration:
      selfRegister: true

If Consul service registration is managed externally from Dapr you need to ensure that the Dapr-to-Dapr internal gRPC port is added to the service metadata under DAPR_PORT (this key is configurable) and that the Consul service Id matches the Dapr app Id. You can then omit selfRegister from the config above.

Behaviour

On init the Consul component either validates the connection to the configured (or default) agent or registers the service if configured to do so. The name resolution interface does not cater for an “on shutdown” pattern so consider this when using Dapr to register services to Consul as it does not deregister services.

The component resolves target apps by filtering healthy services and looks for a DAPR_PORT in the metadata (key is configurable) in order to retrieve the Dapr sidecar port. Consul service.meta is used over service.port so as to not interfere with existing Consul estates.

Spec configuration fields

The configuration spec is fixed to v1.3.0 of the Consul API

Field	Required	Type	Details	Examples
Client	N	api.Config	Configures client connection to the Consul agent. If blank it will use the sdk defaults, which in this case is just an address of `127.0.0.1:8500`	`10.0.4.4:8500`
QueryOptions	N	api.QueryOptions	Configures query used for resolving healthy services, if blank it will default to `UseCache:true`	`UseCache: false`, `Datacenter: “myDC”`
Checks	N	[]api.AgentServiceCheck	Configures health checks if/when registering. If blank it will default to a single health check on the Dapr sidecar health endpoint	See sample configs
Tags	N	`[]string`	Configures any tags to include if/when registering services	`- “dapr”`
Meta	N	`map[string]string`	Configures any additional metadata to include if/when registering services	`DAPR_METRICS_PORT: “${DAPR_METRICS_PORT}”`
DaprPortMetaKey	N	`string`	The key used for getting the Dapr sidecar port from Consul service metadata during service resolution, it will also be used to set the Dapr sidecar port in metadata during registration. If blank it will default to `DAPR_PORT`	`“DAPR_TO_DAPR_PORT”`
SelfRegister	N	`bool`	Controls if Dapr will register the service to Consul. The name resolution interface does not cater for an “on shutdown” pattern so please consider this if using Dapr to register services to Consul as it will not deregister services. If blank it will default to `false`	`true`
AdvancedRegistration	N	api.AgentServiceRegistration	Gives full control of service registration through configuration. If configured the component will ignore any configuration of Checks, Tags, Meta and SelfRegister.	See sample configs

Sample configurations

Basic

The minimum configuration needed is the following:

apiVersion: dapr.io/v1alpha1
kind: Configuration
metadata:
  name: appconfig
spec:
  nameResolution:
    component: "consul"

Registration with additional customizations

Enabling SelfRegister it is then possible to customize the checks, tags and meta

apiVersion: dapr.io/v1alpha1
kind: Configuration
metadata:
  name: appconfig
spec:
  nameResolution:
    component: "consul"
    configuration:
      client:
        address: "127.0.0.1:8500"
      selfRegister: true
      checks:
        - name: "Dapr Health Status"
          checkID: "daprHealth:${APP_ID}"
          interval: "15s"
          http: "http://${HOST_ADDRESS}:${DAPR_HTTP_PORT}/v1.0/healthz"
        - name: "Service Health Status"
          checkID: "serviceHealth:${APP_ID}"
          interval: "15s"
          http: "http://${HOST_ADDRESS}:${APP_PORT}/health"
      tags:
        - "dapr"
        - "v1"
        - "${OTHER_ENV_VARIABLE}"
      meta:
        DAPR_METRICS_PORT: "${DAPR_METRICS_PORT}"
        DAPR_PROFILE_PORT: "${DAPR_PROFILE_PORT}"
      daprPortMetaKey: "DAPR_PORT"        
      queryOptions:
        useCache: true
        filter: "Checks.ServiceTags contains dapr"

Advanced registration

Configuring the advanced registration gives you full control over setting all the Consul properties possible when registering.

apiVersion: dapr.io/v1alpha1
kind: Configuration
metadata:
  name: appconfig
spec:
  nameResolution:
    component: "consul"
    configuration:
      client:
          address: "127.0.0.1:8500"
      selfRegister: false
      queryOptions:
        useCache: true
      daprPortMetaKey: "DAPR_PORT"
      advancedRegistration:
        name: "${APP_ID}"
        port: ${APP_PORT}
        address: "${HOST_ADDRESS}"
        check:
          name: "Dapr Health Status"
          checkID: "daprHealth:${APP_ID}"
          interval: "15s"
          http: "http://${HOST_ADDRESS}:${DAPR_HTTP_PORT}/v1.0/healthz"
        meta:
          DAPR_METRICS_PORT: "${DAPR_METRICS_PORT}"
          DAPR_PROFILE_PORT: "${DAPR_PROFILE_PORT}"
        tags:
          - "dapr"