transformationTemplate

The CEL expression template to apply to transform messages. The following CEL extension functions are provided for use in this CEL expression:

• merge: map1.merge(map2) map3

• Merges the passed CEL map with the existing CEL map the function is applied to.

• If the same key exists in both maps, if the key's value is type map both maps are merged else the value from the passed map is used.

• denormalize: map.denormalize() map

• Denormalizes a CEL map such that every value of type map or key in the map is expanded to return a single level map.

• The resulting keys are "." separated indices of the map keys.

• For example: { "a": 1, "b": { "c": 2, "d": 3 } "e": 4, 5 } .denormalize()

{ "a": 1, "b.c": 2, "b.d": 3, "e.0": 4, "e.1": 5 }

• setField: map.setField(key, value) message

• Sets the field of the message with the given key to the given value.

• If the field is not present it will be added.

• If the field is present it will be overwritten.

• The key can be a dot separated path to set a field in a nested message.

• Key must be of type string.

• Value may be any valid type.

• removeFields: map.removeFields(key1, key2, ...) message

• Removes the fields of the map with the given keys.

• The keys can be a dot separated path to remove a field in a nested message.

• If a key is not found it will be ignored.

• Keys must be of type string.

• toMap: map1, map2, ....toMap() map

• Converts a CEL list of CEL maps to a single CEL map

• toDestinationPayloadFormat(): message.data.toDestinationPayloadFormat() string or bytes

• Converts the message data to the destination payload format specified in Pipeline.Destination.output_payload_format

• This function is meant to be applied to the message.data field.

• If the destination payload format is not set, the function will return the message data unchanged.

• toCloudEventJsonWithPayloadFormat: message.toCloudEventJsonWithPayloadFormat() map

• Converts a message to the corresponding structure of JSON format for CloudEvents

• This function applies toDestinationPayloadFormat() to the message data. It also sets the corresponding datacontenttype of the CloudEvent, as indicated by Pipeline.Destination.output_payload_format. If no output_payload_format is set it will use the existing datacontenttype on the CloudEvent if present, else leave datacontenttype absent.

• This function expects that the content of the message will adhere to the standard CloudEvent format. If it doesn't then this function will fail.

• The result is a CEL map that corresponds to the JSON representation of the CloudEvent. To convert that data to a JSON string it can be chained with the toJsonString function.