Profile (Multi-backend Routing)

A profile connector wraps multiple backend connectors behind a single logical name. Use it when the same data can come from different sources depending on environment, configuration, or availability — for example, fetching prices from a Magento API in production and a local database in development.

Configuration

connector "pricing" {
  type = "profiled"

  select   = "env('PRICE_SOURCE')"    # CEL expression to pick active profile
  default  = "magento"                 # Fallback if select returns empty
  fallback = ["erp", "legacy"]         # Try these if the active profile fails

  profile "magento" {
    type     = "http"
    driver   = "client"
    base_url = "http://magento/api"

    auth {
      type  = "bearer"
      token = env("MAGENTO_TOKEN")
    }

    transform {
      product_id = "input.entity_id"
      sku        = "input.sku"
      price      = "double(input.price)"
      source     = "'magento'"
    }
  }

  profile "erp" {
    type     = "database"
    driver   = "postgres"
    host     = env("ERP_HOST")
    database = "erp"
    user     = env("ERP_USER")
    password = env("ERP_PASSWORD")

    transform {
      product_id = "string(input.id)"
      sku        = "input.codigo"
      price      = "input.precio"
      source     = "'erp'"
    }
  }
}

Options

Option	Type	Description
select	string	CEL expression to determine the active profile
default	string	Default profile when select returns empty
fallback	list	Ordered fallback chain if the active profile fails

Each profile block uses standard connector options for its type (http, database, graphql, etc.) plus an optional transform block to normalize responses to a common format.

Fallback Behavior

When the active profile fails with a retriable error (connection timeout, 5xx): 1. Mycel tries the next profile in the fallback list 2. If all profiles fail, the last error is returned 3. Non-retriable errors (4xx, validation) do not trigger fallback

Metrics

Metric	Description
mycel_connector_profile_active	Currently active profile
mycel_connector_profile_requests_total	Requests per profile
mycel_connector_profile_errors_total	Errors per profile
mycel_connector_profile_fallback_total	Fallback events

Example

flow "get_product_price" {
  from {
    connector = "api"
    operation = "GET /products/:sku/price"
  }
  to   { connector = "pricing" }
}

The flow always targets pricing — the profile connector handles backend selection, fallback, and response normalization transparently.

See the profiles example for a complete working setup.

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Full configuration reference: See Connector Profiles in the Configuration Reference.