Report the size of served artifacts

closes #4602

CHANGES/4602.feature

@@ -0,0 +1 @@
+Added metrics reporting the size of served artifacts.

docs/admin/learn/architecture.md

@@ -179,7 +179,8 @@ Collector here](https://opentelemetry.io/docs/collector/).
 
 - Access to every API endpoint (an HTTP method, target URL, status code, and user agent).
 - Access to every requested package (an HTTP method, target URL, status code, and user agent).
-- Disk usage within a specific domain (total used disk space and the reference to the domain).
+- Disk usage within a specific domain (total used disk space and the reference to a domain). Currently disabled.
+- The size of served artifacts (total count of served data and the reference to a domain).
 
 The information above is sent to the collector in the form of spans and metrics. Thus, the data is
 emitted either based on the user interaction with the system or on a regular basis. Consult

pulpcore/app/models/domain.py

@@ -1,5 +1,3 @@
-from opentelemetry.metrics import Observation
-
 from django.core.files.storage import default_storage
 from django.db import models
 from django_lifecycle import hook, BEFORE_DELETE, BEFORE_UPDATE
@@ -86,16 +84,3 @@ class Meta:
         permissions = [
             ("manage_roles_domain", "Can manage role assignments on domain"),
         ]
-
-
-def disk_usage_callback(domain):
-    from pulpcore.app.models import Artifact
-    from pulpcore.app.util import get_url
-
-    options = yield  # noqa
-    while True:
-        artifacts = Artifact.objects.filter(pulp_domain=domain).only("size")
-        total_size = artifacts.aggregate(size=models.Sum("size", default=0))["size"]
-        options = yield [  # noqa
-            Observation(total_size, {"pulp_href": get_url(domain), "domain_name": domain.name})
-        ]

pulpcore/app/util.py

@@ -516,53 +516,18 @@ def cache_key(base_path):
     return base_path
 
 
-class DomainMetricsEmitterBuilder:
-    """A builder class that initializes an emitter for recording domain's metrics.
+class MetricsEmitter:
+    """
+    A builder class that initializes an emitter.
 
     If Open Telemetry is enabled, the builder configures a real emitter capable of sending data to
-    the collector. Otherwise, a no-op emitter is initialized. The real emitter utilizes the global
-    settings to send metrics.
+    the collector. Otherwise, a no-op emitter is initialized. The real emitter may utilize the
+    global settings to send metrics.
 
     By default, the emitter sends data to the collector every 60 seconds. Adjust the environment
     variable OTEL_METRIC_EXPORT_INTERVAL accordingly if needed.
     """
 
-    class _DomainMetricsEmitter:
-        def __init__(self, domain):
-            self.domain = domain
-            self.meter = metrics.get_meter(f"domain.{domain.name}.meter")
-            self.instrument = self._init_emitting_total_size()
-
-        def _init_emitting_total_size(self):
-            return self.meter.create_observable_gauge(
-                name="disk_usage",
-                description="The total disk size by domain.",
-                callbacks=[self._disk_usage_callback()],
-                unit="Bytes",
-            )
-
-        def _disk_usage_callback(self):
-            try:
-                with PGAdvisoryLock(STORAGE_METRICS_LOCK):
-                    from pulpcore.app.models import Artifact
-
-                    options = yield  # noqa
-
-                    while True:
-                        artifacts = Artifact.objects.filter(pulp_domain=self.domain).only("size")
-                        total_size = artifacts.aggregate(size=Sum("size", default=0))["size"]
-                        options = yield [  # noqa
-                            metrics.Observation(
-                                total_size,
-                                {
-                                    "pulp_href": get_url(self.domain),
-                                    "domain_name": self.domain.name,
-                                },
-                            )
-                        ]
-            except AdvisoryLockError:
-                yield
-
     class _NoopEmitter:
         def __call__(self, *args, **kwargs):
             return self
@@ -571,19 +536,58 @@ def __getattr__(self, *args, **kwargs):
             return self
 
     @classmethod
-    def build(cls, domain):
-        otel_enabled = os.getenv("PULP_OTEL_ENABLED")
-        if otel_enabled == "true" and settings.DOMAIN_ENABLED:
-            return cls._DomainMetricsEmitter(domain)
+    def build(cls, *args, **kwargs):
+        otel_enabled = os.getenv("PULP_OTEL_ENABLED", "").lower() == "true"
+        if otel_enabled and settings.DOMAIN_ENABLED:
+            return cls(*args, **kwargs)
         else:
             return cls._NoopEmitter()
 
 
+class DomainMetricsEmitter(MetricsEmitter):
+    """A builder class that initializes an emitter for recording domain's metrics."""
+
+    def __init__(self, domain):
+        self.domain = domain
+        self.meter = metrics.get_meter(f"domain.{domain.name}.meter")
+        self.instrument = self._init_emitting_total_size()
+
+    def _init_emitting_total_size(self):
+        return self.meter.create_observable_gauge(
+            name="disk_usage",
+            description="The total disk size by domain.",
+            callbacks=[self._disk_usage_callback()],
+            unit="Bytes",
+        )
+
+    def _disk_usage_callback(self):
+        try:
+            with PGAdvisoryLock(STORAGE_METRICS_LOCK):
+                from pulpcore.app.models import Artifact
+
+                options = yield  # noqa
+
+                while True:
+                    artifacts = Artifact.objects.filter(pulp_domain=self.domain).only("size")
+                    total_size = artifacts.aggregate(size=Sum("size", default=0))["size"]
+                    options = yield [  # noqa
+                        metrics.Observation(
+                            total_size,
+                            {
+                                "pulp_href": get_url(self.domain),
+                                "domain_name": self.domain.name,
+                            },
+                        )
+                    ]
+        except AdvisoryLockError:
+            yield
+
+
 def init_domain_metrics_exporter():
     from pulpcore.app.models.domain import Domain
 
     for domain in Domain.objects.all():
-        DomainMetricsEmitterBuilder.build(domain)
+        DomainMetricsEmitter.build(domain)
 
 
 class PGAdvisoryLock:

pulpcore/content/handler.py

@@ -3,7 +3,9 @@
 from multidict import CIMultiDict
 import os
 import re
+import socket
 from gettext import gettext as _
+from functools import lru_cache
 
 from aiohttp.client_exceptions import ClientResponseError
 from aiohttp.web import FileResponse, StreamResponse, HTTPOk
@@ -21,6 +23,8 @@
 
 import django
 
+from opentelemetry import metrics
+
 from pulpcore.constants import STORAGE_RESPONSE_MAP
 from pulpcore.responses import ArtifactResponse
 
@@ -49,7 +53,11 @@
     RemoteArtifact,
 )
 from pulpcore.app import mime_types  # noqa: E402: module level not at top of file
-from pulpcore.app.util import get_domain, cache_key  # noqa: E402: module level not at top of file
+from pulpcore.app.util import (  # noqa: E402: module level not at top of file
+    MetricsEmitter,
+    get_domain,
+    cache_key,
+)
 
 from pulpcore.exceptions import UnsupportedDigestValidationError  # noqa: E402
 
@@ -59,6 +67,11 @@
 log = logging.getLogger(__name__)
 
 
+@lru_cache(maxsize=1)
+def _get_content_app_name():
+    return f"{os.getpid()}@{socket.gethostname()}"
+
+
 class PathNotResolved(HTTPNotFound):
     """
     The path could not be resolved to a published file.
@@ -154,6 +167,20 @@ class Handler:
 
     distribution_model = None
 
+    class ArtifactsSizeCounter(MetricsEmitter):
+        def __init__(self):
+            self.meter = metrics.get_meter("artifacts.size.meter")
+            self.counter = self.meter.create_counter(
+                "artifacts.size.counter",
+                unit="Bytes",
+                description="Counts the size of served artifacts",
+            )
+
+        def add(self, amount, attributes):
+            self.counter.add(amount, attributes)
+
+    artifacts_size_counter = ArtifactsSizeCounter.build()
+
     @staticmethod
     def _reset_db_connection():
         """
@@ -960,13 +987,37 @@ def _set_params_from_headers(hdrs, storage_domain):
                         params[STORAGE_RESPONSE_MAP[storage_domain][a_key]] = hdrs[a_key]
             return params
 
+        def _build_url(**kwargs):
+            filename = os.path.basename(content_artifact.relative_path)
+            content_disposition = f"attachment;filename={filename}"
+
+            headers["Content-Disposition"] = content_disposition
+            parameters = _set_params_from_headers(headers, domain.storage_class)
+            storage_url = storage.url(artifact_name, parameters=parameters, **kwargs)
+
+            return URL(storage_url, encoded=True)
+
         artifact_file = content_artifact.artifact.file
         artifact_name = artifact_file.name
-        filename = os.path.basename(content_artifact.relative_path)
-        content_disposition = f"attachment;filename={filename}"
         domain = get_domain()
         storage = domain.get_storage()
 
+        content_length = artifact_file.size
+
+        try:
+            range_start, range_stop = request.http_range.start, request.http_range.stop
+            if range_start or range_stop:
+                if range_stop and artifact_file.size and range_stop > artifact_file.size:
+                    start = 0 if range_start is None else range_start
+                    content_length = artifact_file.size - start
+                elif range_stop:
+                    content_length = range_stop - range_start
+        except ValueError:
+            size = artifact_file.size or "*"
+            raise HTTPRequestRangeNotSatisfiable(headers={"Content-Range": f"bytes */{size}"})
+
+        self._report_served_artifact_size(content_length)
+
         if domain.storage_class == "pulpcore.app.models.storage.FileSystem":
             path = storage.path(artifact_name)
             if not os.path.exists(path):
@@ -975,25 +1026,12 @@ def _set_params_from_headers(hdrs, storage_domain):
         elif not domain.redirect_to_object_storage:
             return ArtifactResponse(content_artifact.artifact, headers=headers)
         elif domain.storage_class == "storages.backends.s3boto3.S3Boto3Storage":
-            headers["Content-Disposition"] = content_disposition
-            parameters = _set_params_from_headers(headers, domain.storage_class)
-            url = URL(
-                artifact_file.storage.url(
-                    artifact_name, parameters=parameters, http_method=request.method
-                ),
-                encoded=True,
-            )
-            raise HTTPFound(url)
-        elif domain.storage_class == "storages.backends.azure_storage.AzureStorage":
-            headers["Content-Disposition"] = content_disposition
-            parameters = _set_params_from_headers(headers, domain.storage_class)
-            url = URL(artifact_file.storage.url(artifact_name, parameters=parameters), encoded=True)
-            raise HTTPFound(url)
-        elif domain.storage_class == "storages.backends.gcloud.GoogleCloudStorage":
-            headers["Content-Disposition"] = content_disposition
-            parameters = _set_params_from_headers(headers, domain.storage_class)
-            url = URL(artifact_file.storage.url(artifact_name, parameters=parameters), encoded=True)
-            raise HTTPFound(url)
+            raise HTTPFound(_build_url(http_method=request.method))
+        elif domain.storage_class in (
+            "storages.backends.azure_storage.AzureStorage",
+            "storages.backends.gcloud.GoogleCloudStorage",
+        ):
+            raise HTTPFound(_build_url())
         else:
             raise NotImplementedError()
 
@@ -1111,6 +1149,11 @@ async def finalize():
         downloader.finalize = finalize
         download_result = await downloader.run()
 
+        if content_length := response.headers.get("Content-Length"):
+            self._report_served_artifact_size(int(content_length))
+        else:
+            self._report_served_artifact_size(size)
+
         if save_artifact and remote.policy != Remote.STREAMED:
             await asyncio.shield(
                 sync_to_async(self._save_artifact)(download_result, remote_artifact, request)
@@ -1120,3 +1163,10 @@ async def finalize():
         if response.status == 404:
             raise HTTPNotFound()
         return response
+
+    def _report_served_artifact_size(self, size):
+        attributes = {
+            "domain_name": get_domain().name,
+            "content_app_name": _get_content_app_name(),
+        }
+        self.artifacts_size_counter.add(size, attributes)