Add metric for legacy ReleaseFile uploads (#62612)

src/sentry/api/endpoints/project_release_files.py

@@ -20,6 +20,7 @@ from sentry.models.files.file import File
 from sentry.models.release import Release
 from sentry.models.releasefile import ReleaseFile, read_artifact_index
 from sentry.ratelimits.config import SENTRY_RATELIMITER_GROUP_DEFAULTS, RateLimitConfig
+from sentry.utils import metrics
 from sentry.utils.db import atomic_transaction
 
 ERR_FILE_EXISTS = "A file matching this name already exists for the given release"
@@ -158,6 +159,8 @@ class ReleaseFilesMixin:
         file = File.objects.create(name=name, type="release.file", headers=headers)
         file.putfile(fileobj, logger=logger)
 
+        metrics.incr("sourcemaps.upload.single_release_file")
+
         try:
             with atomic_transaction(using=router.db_for_write(ReleaseFile)):
                 releasefile = ReleaseFile.objects.create(