feat: add memory & resource metrics to Python CDK via DogStatsD (Tier 1)

Implements Tier 1 of the metrics initiative per issue #15943:
- New airbyte_cdk/metrics/ module with DogStatsD client
- cgroup v2/v1 memory reading with rusage fallback
- Periodic metric emission during source read() operations
- Graceful no-op when DD_AGENT_HOST is not set
- 34 unit tests covering all code paths

Metrics emitted:
- cdk.memory.usage_bytes: Container memory usage
- cdk.memory.limit_bytes: Container memory limit
- cdk.memory.usage_percent: Usage/limit ratio
- cdk.memory.python_heap_bytes: Python heap via tracemalloc

Co-Authored-By: bot_apk <apk@cognition.ai>

Author: devin-ai-integration[bot]

airbyte_cdk/entrypoint.py

@@ -23,6 +23,7 @@
 from airbyte_cdk.connector import TConfig
 from airbyte_cdk.exception_handler import init_uncaught_exception_handler
 from airbyte_cdk.logger import PRINT_BUFFER, init_logger, is_platform_debug_log_enabled
+from airbyte_cdk.metrics import get_metrics_client
 from airbyte_cdk.models import (
     AirbyteConnectionStatus,
     AirbyteMessage,
@@ -275,10 +276,19 @@ def read(
         if self.source.check_config_against_spec:
             self.validate_connection(source_spec, config)
 
+        # Initialize and emit initial memory metrics
+        metrics_client = get_metrics_client()
+        metrics_client.initialize()
+        metrics_client.emit_memory_metrics()
+
         # The Airbyte protocol dictates that counts be expressed as float/double to better protect against integer overflows
         stream_message_counter: DefaultDict[HashableStreamDescriptor, float] = defaultdict(float)
         for message in self.source.read(self.logger, config, catalog, state):
             yield self.handle_record_counts(message, stream_message_counter)
+            # Periodically emit memory metrics (every 30s by default)
+            metrics_client.maybe_emit_memory_metrics()
+        # Emit final memory metrics snapshot
+        metrics_client.emit_memory_metrics()
         for message in self._emit_queued_messages(self.source):
             yield self.handle_record_counts(message, stream_message_counter)
 

airbyte_cdk/metrics/__init__.py

@@ -0,0 +1,205 @@
+#
+# Copyright (c) 2026 Airbyte, Inc., all rights reserved.
+#
+
+"""
+Metrics module for Python source connectors.
+
+Provides DogStatsD-based metric emission for memory and resource monitoring.
+Designed to be a graceful no-op when DD_AGENT_HOST is not set (local dev, CI).
+"""
+
+import logging
+import os
+import time
+from typing import Optional
+
+from airbyte_cdk.metrics.memory import MemoryInfo, get_memory_info, get_python_heap_bytes
+
+logger = logging.getLogger(__name__)
+
+# Metric names
+METRIC_MEMORY_USAGE_BYTES = "cdk.memory.usage_bytes"
+METRIC_MEMORY_LIMIT_BYTES = "cdk.memory.limit_bytes"
+METRIC_MEMORY_USAGE_PERCENT = "cdk.memory.usage_percent"
+METRIC_MEMORY_PYTHON_HEAP_BYTES = "cdk.memory.python_heap_bytes"
+
+# Default emission interval in seconds
+DEFAULT_EMISSION_INTERVAL_SECONDS = 30.0
+
+
+class MetricsClient:
+    """
+    DogStatsD metrics client for Python source connectors.
+
+    Initializes a DogStatsD client when DD_AGENT_HOST is available,
+    otherwise all metric calls are silent no-ops.
+    """
+
+    def __init__(self) -> None:
+        self._statsd: Optional[object] = None
+        self._tags: list[str] = []
+        self._last_emission_time: float = 0.0
+        self._initialized = False
+
+    def initialize(self) -> None:
+        """
+        Initialize the DogStatsD client if DD_AGENT_HOST is available.
+
+        Should be called once during connector startup. Safe to call multiple times.
+        """
+        if self._initialized:
+            return
+
+        self._initialized = True
+        dd_agent_host = os.environ.get("DD_AGENT_HOST")
+        if not dd_agent_host:
+            logger.debug("DD_AGENT_HOST not set; metrics emission disabled")
+            return
+
+        dd_dogstatsd_port = int(os.environ.get("DD_DOGSTATSD_PORT", "8125"))
+
+        try:
+            from datadog.dogstatsd import DogStatsd
+
+            self._statsd = DogStatsd(
+                host=dd_agent_host,
+                port=dd_dogstatsd_port,
+                # Disable telemetry to reduce overhead
+                disable_telemetry=True,
+            )
+            logger.info(
+                "DogStatsD metrics client initialized (host=%s, port=%d)",
+                dd_agent_host,
+                dd_dogstatsd_port,
+            )
+        except ImportError:
+            logger.warning(
+                "datadog package not installed; metrics emission disabled. "
+                "Install with: pip install datadog"
+            )
+        except Exception:
+            logger.warning(
+                "Failed to initialize DogStatsD client; metrics emission disabled", exc_info=True
+            )
+
+        # Build standard tags from environment
+        self._tags = self._build_tags()
+
+    @property
+    def enabled(self) -> bool:
+        """Return True if the DogStatsD client is active and ready to emit metrics."""
+        return self._statsd is not None
+
+    def _build_tags(self) -> list[str]:
+        """Build standard metric tags from environment variables."""
+        tags: list[str] = []
+
+        # DD_SERVICE and DD_VERSION are set by ConnectorApmSupportHelper
+        dd_service = os.environ.get("DD_SERVICE")
+        if dd_service:
+            tags.append(f"connector:{dd_service}")
+
+        dd_version = os.environ.get("DD_VERSION")
+        if dd_version:
+            tags.append(f"version:{dd_version}")
+
+        # Connection-level tags from platform env vars
+        connection_id = os.environ.get("CONNECTION_ID")
+        if connection_id:
+            tags.append(f"connection_id:{connection_id}")
+
+        workspace_id = os.environ.get("WORKSPACE_ID")
+        if workspace_id:
+            tags.append(f"workspace_id:{workspace_id}")
+
+        return tags
+
+    def gauge(self, metric_name: str, value: float, extra_tags: Optional[list[str]] = None) -> None:
+        """
+        Emit a gauge metric via DogStatsD.
+
+        No-op if the client is not initialized or DD_AGENT_HOST is not set.
+        """
+        if self._statsd is None:
+            return
+
+        tags = self._tags + (extra_tags or [])
+        try:
+            # _statsd is a DogStatsd instance set during initialize(); call gauge directly
+            self._statsd.gauge(metric_name, value, tags=tags)  # type: ignore[union-attr]
+        except Exception:
+            # Never let metric emission failures affect the sync
+            logger.debug("Failed to emit metric %s", metric_name, exc_info=True)
+
+    def emit_memory_metrics(self) -> None:
+        """
+        Read and emit all memory-related metrics.
+
+        Emits:
+        - cdk.memory.usage_bytes: Current container memory usage
+        - cdk.memory.limit_bytes: Container memory limit (if known)
+        - cdk.memory.usage_percent: Usage/limit ratio (if limit is known)
+        - cdk.memory.python_heap_bytes: Python-specific heap via tracemalloc
+        """
+        if not self.enabled:
+            return
+
+        try:
+            info: MemoryInfo = get_memory_info()
+
+            self.gauge(METRIC_MEMORY_USAGE_BYTES, float(info.usage_bytes))
+
+            if info.limit_bytes is not None:
+                self.gauge(METRIC_MEMORY_LIMIT_BYTES, float(info.limit_bytes))
+
+            if info.usage_percent is not None:
+                self.gauge(METRIC_MEMORY_USAGE_PERCENT, info.usage_percent)
+
+            python_heap = get_python_heap_bytes()
+            if python_heap is not None:
+                self.gauge(METRIC_MEMORY_PYTHON_HEAP_BYTES, float(python_heap))
+
+        except Exception:
+            # Never let metric collection failures affect the sync
+            logger.debug("Failed to collect memory metrics", exc_info=True)
+
+    def should_emit(self, interval_seconds: float = DEFAULT_EMISSION_INTERVAL_SECONDS) -> bool:
+        """
+        Check if enough time has passed since the last emission to emit again.
+
+        Returns True if at least interval_seconds have elapsed since the last emission.
+        """
+        now = time.monotonic()
+        if now - self._last_emission_time >= interval_seconds:
+            self._last_emission_time = now
+            return True
+        return False
+
+    def maybe_emit_memory_metrics(
+        self, interval_seconds: float = DEFAULT_EMISSION_INTERVAL_SECONDS
+    ) -> None:
+        """
+        Emit memory metrics if the emission interval has elapsed.
+
+        This is the primary method to call periodically during read() — it handles
+        both the timing check and the metric emission.
+        """
+        if self.enabled and self.should_emit(interval_seconds):
+            self.emit_memory_metrics()
+
+
+# Module-level singleton for convenience
+_metrics_client: Optional[MetricsClient] = None
+
+
+def get_metrics_client() -> MetricsClient:
+    """
+    Get or create the module-level MetricsClient singleton.
+
+    The client is initialized lazily on first access.
+    """
+    global _metrics_client
+    if _metrics_client is None:
+        _metrics_client = MetricsClient()
+    return _metrics_client