Module aws_lambda_powertools.metrics.provider.cloudwatch_emf.cloudwatch
Classes
class AmazonCloudWatchEMFProvider (metric_set: dict[str, Any] | None = None, dimension_set: dict | None = None, namespace: str | None = None, metadata_set: dict[str, Any] | None = None, service: str | None = None, default_dimensions: dict[str, Any] | None = None)-
AmazonCloudWatchEMFProvider creates metrics asynchronously via CloudWatch Embedded Metric Format (EMF).
CloudWatch EMF can create up to 100 metrics per EMF object and metrics, dimensions, and namespace created via AmazonCloudWatchEMFProvider will adhere to the schema, will be serialized and validated against EMF Schema.
Use
Metricsorsingle_metric()to create EMF metrics.Environment Variables
POWERTOOLS_METRICS_NAMESPACE : str metric namespace to be set for all metrics POWERTOOLS_SERVICE_NAME : str service name used for default dimension
Raises
MetricUnitError- When metric unit isn't supported by CloudWatch
MetricResolutionError- When metric resolution isn't supported by CloudWatch
MetricValueError- When metric value isn't a number
SchemaValidationError- When metric object fails EMF schema validation
Expand source code
class AmazonCloudWatchEMFProvider(BaseProvider): """ AmazonCloudWatchEMFProvider creates metrics asynchronously via CloudWatch Embedded Metric Format (EMF). CloudWatch EMF can create up to 100 metrics per EMF object and metrics, dimensions, and namespace created via AmazonCloudWatchEMFProvider will adhere to the schema, will be serialized and validated against EMF Schema. **Use `aws_lambda_powertools.Metrics` or `aws_lambda_powertools.single_metric` to create EMF metrics.** Environment variables --------------------- POWERTOOLS_METRICS_NAMESPACE : str metric namespace to be set for all metrics POWERTOOLS_SERVICE_NAME : str service name used for default dimension Raises ------ MetricUnitError When metric unit isn't supported by CloudWatch MetricResolutionError When metric resolution isn't supported by CloudWatch MetricValueError When metric value isn't a number SchemaValidationError When metric object fails EMF schema validation """ def __init__( self, metric_set: dict[str, Any] | None = None, dimension_set: dict | None = None, namespace: str | None = None, metadata_set: dict[str, Any] | None = None, service: str | None = None, default_dimensions: dict[str, Any] | None = None, ): self.metric_set = metric_set if metric_set is not None else {} self.dimension_set = dimension_set if dimension_set is not None else {} self.default_dimensions = default_dimensions or {} self.namespace = resolve_env_var_choice(choice=namespace, env=os.getenv(constants.METRICS_NAMESPACE_ENV)) self.service = resolve_env_var_choice(choice=service, env=os.getenv(constants.SERVICE_NAME_ENV)) self.metadata_set = metadata_set if metadata_set is not None else {} self.timestamp: int | None = None self._metric_units = [unit.value for unit in MetricUnit] self._metric_unit_valid_options = list(MetricUnit.__members__) self._metric_resolutions = [resolution.value for resolution in MetricResolution] self.dimension_set.update(**self.default_dimensions) def add_metric( self, name: str, unit: MetricUnit | str, value: float, resolution: MetricResolution | int = 60, ) -> None: """Adds given metric Example ------- **Add given metric using MetricUnit enum** metric.add_metric(name="BookingConfirmation", unit=MetricUnit.Count, value=1) **Add given metric using plain string as value unit** metric.add_metric(name="BookingConfirmation", unit="Count", value=1) **Add given metric with MetricResolution non default value** metric.add_metric(name="BookingConfirmation", unit="Count", value=1, resolution=MetricResolution.High) Parameters ---------- name : str Metric name unit : MetricUnit | str `aws_lambda_powertools.helper.models.MetricUnit` value : float Metric value resolution : MetricResolution | int `aws_lambda_powertools.helper.models.MetricResolution` Raises ------ MetricUnitError When metric unit is not supported by CloudWatch MetricResolutionError When metric resolution is not supported by CloudWatch """ if not isinstance(value, numbers.Number): raise MetricValueError(f"{value} is not a valid number") unit = extract_cloudwatch_metric_unit_value( metric_units=self._metric_units, metric_valid_options=self._metric_unit_valid_options, unit=unit, ) resolution = extract_cloudwatch_metric_resolution_value( metric_resolutions=self._metric_resolutions, resolution=resolution, ) metric: dict = self.metric_set.get(name, defaultdict(list)) metric["Unit"] = unit metric["StorageResolution"] = resolution metric["Value"].append(float(value)) logger.debug(f"Adding metric: {name} with {metric}") self.metric_set[name] = metric if len(self.metric_set) == MAX_METRICS or len(metric["Value"]) == MAX_METRICS: logger.debug(f"Exceeded maximum of {MAX_METRICS} metrics - Publishing existing metric set") metrics = self.serialize_metric_set() print(json.dumps(metrics)) # clear metric set only as opposed to metrics and dimensions set # since we could have more than 100 metrics self.metric_set.clear() def serialize_metric_set( self, metrics: dict | None = None, dimensions: dict | None = None, metadata: dict | None = None, ) -> CloudWatchEMFOutput: """Serializes metric and dimensions set Parameters ---------- metrics : dict, optional Dictionary of metrics to serialize, by default None dimensions : dict, optional Dictionary of dimensions to serialize, by default None metadata: dict, optional Dictionary of metadata to serialize, by default None Example ------- **Serialize metrics into EMF format** metrics = MetricManager() # ...add metrics, dimensions, namespace ret = metrics.serialize_metric_set() Returns ------- CloudWatchEMFOutput Serialized metrics following EMF specification Raises ------ SchemaValidationError Raised when serialization fail schema validation """ if metrics is None: # pragma: no cover metrics = self.metric_set if dimensions is None: # pragma: no cover dimensions = self.dimension_set if metadata is None: # pragma: no cover metadata = self.metadata_set if self.service and not self.dimension_set.get("service"): # self.service won't be a float self.add_dimension(name="service", value=self.service) if len(metrics) == 0: raise SchemaValidationError("Must contain at least one metric.") if self.namespace is None: raise SchemaValidationError("Must contain a metric namespace.") logger.debug({"details": "Serializing metrics", "metrics": metrics, "dimensions": dimensions}) # For standard resolution metrics, don't add StorageResolution field to avoid unnecessary ingestion of data into cloudwatch # noqa E501 # Example: [ { "Name": "metric_name", "Unit": "Count"} ] # noqa ERA001 # # In case using high-resolution metrics, add StorageResolution field # Example: [ { "Name": "metric_name", "Unit": "Count", "StorageResolution": 1 } ] # noqa ERA001 metric_definition: list[MetricNameUnitResolution] = [] metric_names_and_values: dict[str, float] = {} # { "metric_name": 1.0 } for metric_name in metrics: metric: dict = metrics[metric_name] metric_value: int = metric.get("Value", 0) metric_unit: str = metric.get("Unit", "") metric_resolution: int = metric.get("StorageResolution", 60) metric_definition_data: MetricNameUnitResolution = {"Name": metric_name, "Unit": metric_unit} # high-resolution metrics if metric_resolution == 1: metric_definition_data["StorageResolution"] = metric_resolution metric_definition.append(metric_definition_data) metric_names_and_values.update({metric_name: metric_value}) return { "_aws": { "Timestamp": self.timestamp or int(datetime.datetime.now().timestamp() * 1000), # epoch "CloudWatchMetrics": [ { "Namespace": self.namespace, # "test_namespace" "Dimensions": [list(dimensions.keys())], # [ "service" ] "Metrics": metric_definition, }, ], }, # NOTE: Mypy doesn't recognize splats '** syntax' in TypedDict **dimensions, # "service": "test_service" **metadata, # type: ignore[typeddict-item] # "username": "test" **metric_names_and_values, # "single_metric": 1.0 } def add_dimension(self, name: str, value: str) -> None: """Adds given dimension to all metrics Example ------- **Add a metric dimensions** metric.add_dimension(name="operation", value="confirm_booking") Parameters ---------- name : str Dimension name value : str Dimension value """ logger.debug(f"Adding dimension: {name}:{value}") if len(self.dimension_set) == MAX_DIMENSIONS: raise SchemaValidationError( f"Maximum number of dimensions exceeded ({MAX_DIMENSIONS}): Unable to add dimension {name}.", ) value = value if isinstance(value, str) else str(value) if not name.strip() or not value.strip(): warnings.warn( f"The dimension {name} doesn't meet the requirements and won't be added. " "Ensure the dimension name and value are non empty strings", stacklevel=2, ) else: # Cast value to str according to EMF spec # Majority of values are expected to be string already, so # checking before casting improves performance in most cases self.dimension_set[name] = value def add_metadata(self, key: str, value: Any) -> None: """Adds high cardinal metadata for metrics object This will not be available during metrics visualization. Instead, this will be searchable through logs. If you're looking to add metadata to filter metrics, then use add_dimensions method. Example ------- **Add metrics metadata** metric.add_metadata(key="booking_id", value="booking_id") Parameters ---------- key : str Metadata key value : any Metadata value """ logger.debug(f"Adding metadata: {key}:{value}") # Cast key to str according to EMF spec # Majority of keys are expected to be string already, so # checking before casting improves performance in most cases if isinstance(key, str): self.metadata_set[key] = value else: self.metadata_set[str(key)] = value def set_timestamp(self, timestamp: int | datetime.datetime): """ Set the timestamp for the metric. Parameters: ----------- timestamp: int | datetime.datetime The timestamp to create the metric. If an integer is provided, it is assumed to be the epoch time in milliseconds. If a datetime object is provided, it will be converted to epoch time in milliseconds. """ # The timestamp must be a Datetime object or an integer representing an epoch time. # This should not exceed 14 days in the past or be more than 2 hours in the future. # Any metrics failing to meet this criteria will be skipped by Amazon CloudWatch. # See: https://docs.aws.amazon.com/AmazonCloudWatch/latest/monitoring/CloudWatch_Embedded_Metric_Format_Specification.html # See: https://docs.aws.amazon.com/AmazonCloudWatch/latest/logs/CloudWatch-Logs-Monitoring-CloudWatch-Metrics.html if not validate_emf_timestamp(timestamp): warnings.warn( "This metric doesn't meet the requirements and will be skipped by Amazon CloudWatch. " "Ensure the timestamp is within 14 days past or 2 hours future.", stacklevel=2, ) self.timestamp = convert_timestamp_to_emf_format(timestamp) def clear_metrics(self) -> None: logger.debug("Clearing out existing metric set from memory") self.metric_set.clear() self.dimension_set.clear() self.metadata_set.clear() self.set_default_dimensions(**self.default_dimensions) def flush_metrics(self, raise_on_empty_metrics: bool = False) -> None: """Manually flushes the metrics. This is normally not necessary, unless you're running on other runtimes besides Lambda, where the @log_metrics decorator already handles things for you. Parameters ---------- raise_on_empty_metrics : bool, optional raise exception if no metrics are emitted, by default False """ if not raise_on_empty_metrics and not self.metric_set: warnings.warn( "No application metrics to publish. The cold-start metric may be published if enabled. " "If application metrics should never be empty, consider using 'raise_on_empty_metrics'", stacklevel=2, ) else: logger.debug("Flushing existing metrics") metrics = self.serialize_metric_set() print(json.dumps(metrics, separators=(",", ":"))) self.clear_metrics() def log_metrics( self, lambda_handler: AnyCallableT | None = None, capture_cold_start_metric: bool = False, raise_on_empty_metrics: bool = False, **kwargs, ): """Decorator to serialize and publish metrics at the end of a function execution. Be aware that the log_metrics **does call* the decorated function (e.g. lambda_handler). Example ------- **Lambda function using tracer and metrics decorators** from aws_lambda_powertools import Metrics, Tracer metrics = Metrics(service="payment") tracer = Tracer(service="payment") @tracer.capture_lambda_handler @metrics.log_metrics def handler(event, context): ... Parameters ---------- lambda_handler : Callable[[Any, Any], Any], optional lambda function handler, by default None capture_cold_start_metric : bool, optional captures cold start metric, by default False raise_on_empty_metrics : bool, optional raise exception if no metrics are emitted, by default False **kwargs Raises ------ e Propagate error received """ default_dimensions = kwargs.get("default_dimensions") if default_dimensions: self.set_default_dimensions(**default_dimensions) return super().log_metrics( lambda_handler=lambda_handler, capture_cold_start_metric=capture_cold_start_metric, raise_on_empty_metrics=raise_on_empty_metrics, **kwargs, ) def add_cold_start_metric(self, context: LambdaContext) -> None: """Add cold start metric and function_name dimension Parameters ---------- context : Any Lambda context """ logger.debug("Adding cold start metric and function_name dimension") with single_metric(name="ColdStart", unit=MetricUnit.Count, value=1, namespace=self.namespace) as metric: metric.add_dimension(name="function_name", value=context.function_name) if self.service: metric.add_dimension(name="service", value=str(self.service)) def set_default_dimensions(self, **dimensions) -> None: """Persist dimensions across Lambda invocations Parameters ---------- dimensions : dict[str, Any], optional metric dimensions as key=value Example ------- **Sets some default dimensions that will always be present across metrics and invocations** from aws_lambda_powertools import Metrics metrics = Metrics(namespace="ServerlessAirline", service="payment") metrics.set_default_dimensions(environment="demo", another="one") @metrics.log_metrics() def lambda_handler(): return True """ for name, value in dimensions.items(): self.add_dimension(name, value) self.default_dimensions.update(**dimensions)Ancestors
- BaseProvider
- abc.ABC
Methods
def add_cold_start_metric(self, context: LambdaContext)-
Add cold start metric and function_name dimension
Parameters
context:Any- Lambda context
def add_dimension(self, name: str, value: str) ‑> None-
Adds given dimension to all metrics
Example
Add a metric dimensions
metric.add_dimension(name="operation", value="confirm_booking")Parameters
name:str- Dimension name
value:str- Dimension value
def add_metadata(self, key: str, value: Any) ‑> None-
Adds high cardinal metadata for metrics object
This will not be available during metrics visualization. Instead, this will be searchable through logs.
If you're looking to add metadata to filter metrics, then use add_dimensions method.
Example
Add metrics metadata
metric.add_metadata(key="booking_id", value="booking_id")Parameters
key:str- Metadata key
value:any- Metadata value
def add_metric(self, name: str, unit: MetricUnit | str, value: float, resolution: MetricResolution | int = 60) ‑> None-
Adds given metric
Example
Add given metric using MetricUnit enum
metric.add_metric(name="BookingConfirmation", unit=MetricUnit.Count, value=1)Add given metric using plain string as value unit
metric.add_metric(name="BookingConfirmation", unit="Count", value=1)Add given metric with MetricResolution non default value
metric.add_metric(name="BookingConfirmation", unit="Count", value=1, resolution=MetricResolution.High)Parameters
name:str- Metric name
unit:MetricUnit | straws_lambda_powertools.helper.models.MetricUnitvalue:float- Metric value
resolution:MetricResolution | intaws_lambda_powertools.helper.models.MetricResolution
Raises
MetricUnitError- When metric unit is not supported by CloudWatch
MetricResolutionError- When metric resolution is not supported by CloudWatch
def flush_metrics(self, raise_on_empty_metrics: bool = False) ‑> None-
Manually flushes the metrics. This is normally not necessary, unless you're running on other runtimes besides Lambda, where the @log_metrics decorator already handles things for you.
Parameters
raise_on_empty_metrics:bool, optional- raise exception if no metrics are emitted, by default False
def log_metrics(self, lambda_handler: AnyCallableT | None = None, capture_cold_start_metric: bool = False, raise_on_empty_metrics: bool = False, **kwargs)-
Decorator to serialize and publish metrics at the end of a function execution.
Be aware that the log_metrics *does call the decorated function (e.g. lambda_handler).
Example
Lambda function using tracer and metrics decorators
from aws_lambda_powertools import Metrics, Tracer metrics = Metrics(service="payment") tracer = Tracer(service="payment") @tracer.capture_lambda_handler @metrics.log_metrics def handler(event, context): ...Parameters
lambda_handler:Callable[[Any, Any], Any], optional- lambda function handler, by default None
capture_cold_start_metric:bool, optional- captures cold start metric, by default False
raise_on_empty_metrics:bool, optional- raise exception if no metrics are emitted, by default False
**kwargs
Raises
e- Propagate error received
def serialize_metric_set(self, metrics: dict | None = None, dimensions: dict | None = None, metadata: dict | None = None)-
Serializes metric and dimensions set
Parameters
metrics:dict, optional- Dictionary of metrics to serialize, by default None
dimensions:dict, optional- Dictionary of dimensions to serialize, by default None
metadata:dict, optional- Dictionary of metadata to serialize, by default None
Example
Serialize metrics into EMF format
metrics = MetricManager() # ...add metrics, dimensions, namespace ret = metrics.serialize_metric_set()Returns
CloudWatchEMFOutput- Serialized metrics following EMF specification
Raises
SchemaValidationError- Raised when serialization fail schema validation
def set_default_dimensions(self, **dimensions) ‑> None-
Persist dimensions across Lambda invocations
Parameters
dimensions:dict[str, Any], optional- metric dimensions as key=value
Example
Sets some default dimensions that will always be present across metrics and invocations
from aws_lambda_powertools import Metrics metrics = Metrics(namespace="ServerlessAirline", service="payment") metrics.set_default_dimensions(environment="demo", another="one") @metrics.log_metrics() def lambda_handler(): return True def set_timestamp(self, timestamp: int | datetime.datetime)-
Set the timestamp for the metric.
Parameters:
timestamp: int | datetime.datetime The timestamp to create the metric. If an integer is provided, it is assumed to be the epoch time in milliseconds. If a datetime object is provided, it will be converted to epoch time in milliseconds.
Inherited members