Faas

Function as a Service Attributes

FaaS attributes

Attribute	Type	Description	Examples	Stability
faas.coldstart	boolean	A boolean that is true if the serverless function is executed for the first time (aka cold-start).
faas.cron	string	A string containing the schedule period as Cron Expression.	0/5 * * * ? *
faas.document.collection	string	The name of the source on which the triggering operation was performed. For example, in Cloud Storage or S3 corresponds to the bucket name, and in Cosmos DB to the database name.	myBucketName; myDbName
faas.document.name	string	The document name/table subjected to the operation. For example, in Cloud Storage or S3 is the name of the file, and in Cosmos DB the table name.	myFile.txt; myTableName
faas.document.operation	string	Describes the type of the operation that was performed on the data.	insert; edit; delete
faas.document.time	string	A string containing the time when the data was accessed in the ISO 8601 format expressed in UTC.	2020-01-23T13:47:06Z
faas.instance	string	The execution environment ID as a string, that will be potentially reused for other invocations to the same function/function version. [1]	2021/06/28/[$LATEST]2f399eb14537447da05ab2a2e39309de
faas.invocation_id	string	The invocation ID of the current function invocation.	af9d5aa4-a685-4c5f-a22b-444f80b3cc28
faas.invoked_name	string	The name of the invoked function. [2]	my-function
faas.invoked_provider	string	The cloud provider of the invoked function. [3]	alibaba_cloud; aws; azure
faas.invoked_region	string	The cloud region of the invoked function. [4]	eu-central-1
faas.max_memory	int	The amount of memory available to the serverless function converted to Bytes. [5]	134217728
faas.name	string	The name of the single function that this runtime instance executes. [6]	my-function; myazurefunctionapp/some-function-name
faas.time	string	A string containing the function invocation time in the ISO 8601 format expressed in UTC.	2020-01-23T13:47:06Z
faas.trigger	string	Type of the trigger which caused this function invocation.	datasource; http; pubsub
faas.version	string	The immutable version of the function being executed. [7]	26; pinkfroid-00002

[1]: * AWS Lambda: Use the (full) log stream name.

[2]: SHOULD be equal to the faas.name resource attribute of the invoked function.

[3]: SHOULD be equal to the cloud.provider resource attribute of the invoked function.

[4]: SHOULD be equal to the cloud.region resource attribute of the invoked function.

[5]: It’s recommended to set this attribute since e.g. too little memory can easily stop a Java AWS Lambda function from working correctly. On AWS Lambda, the environment variable AWS_LAMBDA_FUNCTION_MEMORY_SIZE provides this information (which must be multiplied by 1,048,576).

[6]: This is the name of the function as configured/deployed on the FaaS platform and is usually different from the name of the callback function (which may be stored in the code.namespace/code.function span attributes).

For some cloud providers, the above definition is ambiguous. The following definition of function name MUST be used for this attribute (and consequently the span name) for the listed cloud providers/products:

• Azure: The full name <FUNCAPP>/<FUNC>, i.e., function app name followed by a forward slash followed by the function name (this form can also be seen in the resource JSON for the function). This means that a span attribute MUST be used, as an Azure function app can host multiple functions that would usually share a TracerProvider (see also the cloud.resource_id attribute).

[7]: Depending on the cloud provider and platform, use:

• AWS Lambda: The function version (an integer represented as a decimal string).
• Google Cloud Run (Services): The revision (i.e., the function name plus the revision suffix).
• Google Cloud Functions: The value of the K_REVISION environment variable.
• Azure Functions: Not applicable. Do not set this attribute.

faas.document.operation has the following list of well-known values. If one of them applies, then the respective value MUST be used; otherwise, a custom value MAY be used.

Value	Description	Stability
delete	When an object is deleted.
edit	When an object is modified.
insert	When a new object is created.

faas.invoked_provider has the following list of well-known values. If one of them applies, then the respective value MUST be used; otherwise, a custom value MAY be used.

Value	Description	Stability
alibaba_cloud	Alibaba Cloud
aws	Amazon Web Services
azure	Microsoft Azure
gcp	Google Cloud Platform
tencent_cloud	Tencent Cloud

faas.trigger has the following list of well-known values. If one of them applies, then the respective value MUST be used; otherwise, a custom value MAY be used.

Value	Description	Stability
datasource	A response to some data source operation such as a database or filesystem read/write
http	To provide an answer to an inbound HTTP request
other	If none of the others apply
pubsub	A function is set to be executed when messages are sent to a messaging system
timer	A function is scheduled to be executed regularly