Changing metrics flush decision

Author: leandrodamascena

aws_lambda_powertools/metrics/functions.py

@@ -10,7 +10,7 @@
 )
 from aws_lambda_powertools.metrics.provider.cloudwatch_emf.metric_properties import MetricResolution, MetricUnit
 from aws_lambda_powertools.shared import constants
-from aws_lambda_powertools.shared.functions import resolve_truthy_env_var_choice
+from aws_lambda_powertools.shared.functions import strtobool
 
 logger = logging.getLogger(__name__)
 
@@ -142,24 +142,25 @@ def convert_timestamp_to_emf_format(timestamp: int | datetime) -> int:
 
 
 def is_metrics_disabled() -> bool:
-    """Checks if metrics have been disabled via POWERTOOLS_METRICS_DISABLED or POWERTOOLS_DEV
+    """
+    Determine if metrics should be disabled based on environment variables.
 
     Returns:
-        bool: True if metrics are disabled, False otherwise
+        bool: True if metrics are disabled, False otherwise.
+
+    Rules:
+    - If POWERTOOLS_DEV is True and POWERTOOLS_METRICS_DISABLED is True: Disable metrics
+    - If POWERTOOLS_METRICS_DISABLED is True: Disable metrics
+    - If POWERTOOLS_DEV is True and POWERTOOLS_METRICS_DISABLED is not set: Disable metrics
     """
-    # First check POWERTOOLS_METRICS_DISABLED as it should take precedence
-    if constants.METRICS_DISABLED_ENV in os.environ:
-        env_value = os.getenv(constants.METRICS_DISABLED_ENV)
-        is_disabled = resolve_truthy_env_var_choice(env=env_value or "false")
-        if is_disabled:
-            logger.debug("Metrics have been disabled via env var POWERTOOLS_METRICS_DISABLED")
-        return bool(is_disabled)
-
-    # Then check if POWERTOOLS_DEV is enabled
-    dev_mode_value = os.getenv(constants.POWERTOOLS_DEV_ENV)
-    dev_mode = resolve_truthy_env_var_choice(env=dev_mode_value or "false")
-    if dev_mode:
-        logger.debug("Metrics have been disabled via env var POWERTOOLS_DEV")
-        return True
-
-    return False
+
+    is_dev_mode = strtobool(os.getenv(constants.POWERTOOLS_DEV_ENV, "false"))
+    is_metrics_disabled = strtobool(os.getenv(constants.METRICS_DISABLED_ENV, "false"))
+
+    disable_conditions = [
+        is_metrics_disabled,
+        is_metrics_disabled and is_dev_mode,
+        is_dev_mode and os.getenv(constants.METRICS_DISABLED_ENV) is None,
+    ]
+
+    return any(disable_conditions)

aws_lambda_powertools/metrics/provider/cloudwatch_emf/cloudwatch.py

@@ -78,7 +78,6 @@ def __init__(
         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.metrics_disabled = is_metrics_disabled()
 
         self.metadata_set = metadata_set if metadata_set is not None else {}
         self.timestamp: int | None = None
@@ -379,7 +378,7 @@ def flush_metrics(self, raise_on_empty_metrics: bool = False) -> None:
                 "If application metrics should never be empty, consider using 'raise_on_empty_metrics'",
                 stacklevel=2,
             )
-        elif not self.metrics_disabled:
+        elif not is_metrics_disabled():
             logger.debug("Flushing existing metrics")
             metrics = self.serialize_metric_set()
             print(json.dumps(metrics, separators=(",", ":")))

aws_lambda_powertools/metrics/provider/datadog/datadog.py

@@ -66,7 +66,6 @@ def __init__(
         )
         self.default_tags = default_tags or {}
         self.flush_to_log = resolve_env_var_choice(choice=flush_to_log, env=os.getenv(constants.DATADOG_FLUSH_TO_LOG))
-        self.metrics_disabled = is_metrics_disabled()
 
     #  adding name,value,timestamp,tags
     def add_metric(
@@ -202,7 +201,7 @@ def flush_metrics(self, raise_on_empty_metrics: bool = False) -> None:
                         timestamp=metric_item["e"],
                         tags=metric_item["t"],
                     )
-            elif not self.metrics_disabled:
+            elif not is_metrics_disabled():
                 # dd module not found: flush to log, this format can be recognized via datadog log forwarder
                 # https://github.com/Datadog/datadog-lambda-python/blob/main/datadog_lambda/metric.py#L77
                 for metric_item in metrics:

docs/core/metrics.md

@@ -36,13 +36,13 @@ If you're new to Amazon CloudWatch, there are five terminologies you must be awa
 
 Metric has three global settings that will be used across all metrics emitted:
 
-| Setting              | Description                                                                     | Environment variable           | Constructor parameter |
-| -------------------- | ------------------------------------------------------------------------------- | ------------------------------ | --------------------- |
-| **Metric namespace** | Logical container where all metrics will be placed e.g. `ServerlessAirline`     | `POWERTOOLS_METRICS_NAMESPACE` | `namespace`           |
-| **Service**          | Optionally, sets **service** metric dimension across all metrics e.g. `payment` | `POWERTOOLS_SERVICE_NAME`      | `service`             |
-| **Disable Powertools Metrics**          | Optionally, disables all Powertools metrics.	 | `POWERTOOLS_METRICS_DISABLED`      | N/A            |
+| Setting                         | Description                                                                     | Environment variable           | Constructor parameter |
+| ------------------------------- | ------------------------------------------------------------------------------- | ------------------------------ | --------------------- |
+| **Metric namespace**            | Logical container where all metrics will be placed e.g. `ServerlessAirline`     | `POWERTOOLS_METRICS_NAMESPACE` | `namespace`           |
+| **Service**                     | Optionally, sets **service** metric dimension across all metrics e.g. `payment` | `POWERTOOLS_SERVICE_NAME`      | `service`             |
+| **Disable Powertools Metrics**  | Optionally, disables all Powertools metrics.	                                | `POWERTOOLS_METRICS_DISABLED`  | N/A                   |
 
-???+ warning
+???+ info
     `POWERTOOLS_METRICS_DISABLED` will not disable default metrics created by AWS services.
 
 ???+ tip

docs/core/metrics/datadog.md

@@ -174,13 +174,13 @@ This has the advantage of keeping cold start metric separate from your applicati
 
 You can use any of the following environment variables to configure `DatadogMetrics`:
 
-| Setting              | Description                                                                      | Environment variable           | Constructor parameter |
-| -------------------- | -------------------------------------------------------------------------------- | ------------------------------ | --------------------- |
-| **Metric namespace** | Logical container where all metrics will be placed e.g. `ServerlessAirline`      | `POWERTOOLS_METRICS_NAMESPACE` | `namespace`           |
-| **Flush to log**     | Use this when you want to flush metrics to be exported through Datadog Forwarder | `DD_FLUSH_TO_LOG`              | `flush_to_log`        |
-| **Disable Powertools Metrics**          | Optionally, disables all Powertools metrics.	 | `POWERTOOLS_METRICS_DISABLED`      | N/A            |
+| Setting                        | Description                                                                      | Environment variable           | Constructor parameter |
+| ------------------------------ | -------------------------------------------------------------------------------- | ------------------------------ | --------------------- |
+| **Metric namespace**           | Logical container where all metrics will be placed e.g. `ServerlessAirline`      | `POWERTOOLS_METRICS_NAMESPACE` | `namespace`           |
+| **Flush to log**               | Use this when you want to flush metrics to be exported through Datadog Forwarder | `DD_FLUSH_TO_LOG`              | `flush_to_log`        |
+| **Disable Powertools Metrics** | Optionally, disables all Powertools metrics.	                                    | `POWERTOOLS_METRICS_DISABLED`  | N/A                   |
 
-???+ warning
+???+ info
     `POWERTOOLS_METRICS_DISABLED` will not disable default metrics created by AWS services.
 
 ## Advanced