feat: Emit target metrics

singer_sdk/io_base.py

@@ -6,10 +6,12 @@
 import decimal
 import json
 import logging
+import os
 import sys
 import typing as t
 from collections import Counter, defaultdict
 
+from singer_sdk import metrics
 from singer_sdk._singerlib.messages import Message, SingerMessageType
 from singer_sdk._singerlib.messages import format_message as singer_format_message
 from singer_sdk._singerlib.messages import write_message as singer_write_message
@@ -33,8 +35,14 @@ def listen(self, file_input: t.IO[str] | None = None) -> None:
         if not file_input:
             file_input = sys.stdin
 
-        self._process_lines(file_input)
-        self._process_endofpipe()
+        load_timer = metrics.Timer(
+            metrics.Metric.SYNC_DURATION,
+            {"pid": os.getpid()},
+        )
+
+        with load_timer:
+            self._process_lines(file_input)
+            self._process_endofpipe()
 
     @staticmethod
     def _assert_line_requires(line_dict: dict, requires: set[str]) -> None:
@@ -83,30 +91,37 @@ def _process_lines(self, file_input: t.IO[str]) -> t.Counter[str]:
             A counter object for the processed lines.
         """
         stats: dict[str, int] = defaultdict(int)
-        for line in file_input:
-            line_dict = self.deserialize_json(line)
-            self._assert_line_requires(line_dict, requires={"type"})
+        record_message_counter = metrics.Counter(
+            metrics.Metric.MESSAGE_COUNT,
+            {"pid": os.getpid()},
+            log_interval=metrics.DEFAULT_LOG_INTERVAL,
+        )
+        with record_message_counter:
+            for line in file_input:
+                line_dict = self.deserialize_json(line)
+                self._assert_line_requires(line_dict, requires={"type"})
 
-            record_type: SingerMessageType = line_dict["type"]
-            if record_type == SingerMessageType.SCHEMA:
-                self._process_schema_message(line_dict)
+                record_type: SingerMessageType = line_dict["type"]
+                if record_type == SingerMessageType.SCHEMA:
+                    self._process_schema_message(line_dict)
 
-            elif record_type == SingerMessageType.RECORD:
-                self._process_record_message(line_dict)
+                elif record_type == SingerMessageType.RECORD:
+                    record_message_counter.increment()
+                    self._process_record_message(line_dict)
 
-            elif record_type == SingerMessageType.ACTIVATE_VERSION:
-                self._process_activate_version_message(line_dict)
+                elif record_type == SingerMessageType.ACTIVATE_VERSION:
+                    self._process_activate_version_message(line_dict)
 
-            elif record_type == SingerMessageType.STATE:
-                self._process_state_message(line_dict)
+                elif record_type == SingerMessageType.STATE:
+                    self._process_state_message(line_dict)
 
-            elif record_type == SingerMessageType.BATCH:
-                self._process_batch_message(line_dict)
+                elif record_type == SingerMessageType.BATCH:
+                    self._process_batch_message(line_dict)
 
-            else:
-                self._process_unknown_message(line_dict)
+                else:
+                    self._process_unknown_message(line_dict)
 
-            stats[record_type] += 1
+                stats[record_type] += 1
 
         return Counter(**stats)
 

singer_sdk/metrics.py

@@ -45,6 +45,7 @@ class Tag(str, enum.Enum):
     JOB_TYPE = "job_type"
     HTTP_STATUS_CODE = "http_status_code"
     STATUS = "status"
+    PID = "pid"
 
 
 class Metric(str, enum.Enum):
@@ -56,6 +57,7 @@ class Metric(str, enum.Enum):
     HTTP_REQUEST_COUNT = "http_request_count"
     JOB_DURATION = "job_duration"
     SYNC_DURATION = "sync_duration"
+    MESSAGE_COUNT = "message_count"
 
 
 @dataclass
@@ -180,6 +182,10 @@ def __init__(
         self.log_interval = log_interval
         self.last_log_time = time()
 
+    def exit(self) -> None:
+        """Exit the counter context."""
+        self._pop()
+
     def __enter__(self) -> Counter:
         """Enter the counter context.
 
@@ -202,7 +208,7 @@ def __exit__(
             exc_val: The exception value.
             exc_tb: The exception traceback.
         """
-        self._pop()
+        self.exit()
 
     def _pop(self) -> None:
         """Log and reset the counter."""

singer_sdk/sinks/core.py

@@ -7,6 +7,7 @@
 import datetime
 import importlib.util
 import json
+import os
 import time
 import typing as t
 from functools import cached_property
@@ -17,6 +18,7 @@
 import jsonschema
 from typing_extensions import override
 
+from singer_sdk import metrics
 from singer_sdk.exceptions import (
     InvalidJSONSchema,
     InvalidRecord,
@@ -188,6 +190,23 @@ def __init__(
         )
 
         self._validator: BaseJSONSchemaValidator | None = self.get_validator()
+        self._record_counter: metrics.Counter = metrics.Counter(
+            metrics.Metric.RECORD_COUNT,
+            {
+                metrics.Tag.STREAM: stream_name,
+                metrics.Tag.PID: os.getpid(),
+            },
+            log_interval=metrics.DEFAULT_LOG_INTERVAL,
+        )
+
+    @property
+    def record_counter_metric(self) -> metrics.Counter:
+        """Get the record counter metric.
+
+        Returns:
+            The record counter metric.
+        """
+        return self._record_counter
 
     @cached_property
     def validate_schema(self) -> bool:
@@ -680,6 +699,7 @@ def clean_up(self) -> None:
         should not be relied on, it's recommended to use a uuid as well.
         """
         self.logger.info("Cleaning up %s", self.stream_name)
+        self.record_counter_metric.exit()
 
     def process_batch_files(
         self,

singer_sdk/target_base.py

@@ -360,6 +360,7 @@ def _process_record_message(self, message_dict: dict) -> None:
 
             sink.tally_record_read()
             sink.process_record(transformed_record, context)
+            sink.record_counter_metric.increment()
             sink._after_process_record(context)  # noqa: SLF001
 
             if sink.is_full: