[AzureMonitorAutoConfigure] Add customer-facing SDKStats metrics (Item_Success_Count, Item_Dropped_Count, Item_Retry_Count)

[rajkumar-rangaraj]

Description

PR: Add customer-facing SDKStats metrics (Item_Success_Count, Item_Dropped_Count, Item_Retry_Count)

Implements customer-facing SDKStats per spec. The exporter now tracks per-telemetry-type success, drop, and retry counts and periodically exports them as Metric TelemetryItems through the existing pipeline to the customer's own Application Insights resource.

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New files

Production

File	Purpose
CustomerSdkStats.java	Thread-safe accumulator (ConcurrentHashMap<Key, AtomicLong>) for three counter families: successCounts, droppedCounts, retryCounts. collectAndReset() atomically snapshots and clears all counters, returning a list of TelemetryItem metrics with the correct dimensions (computeType, language, version, telemetry_type, telemetry_success, drop.code/drop.reason, retry.code/retry.reason). Static factory create(version) auto-detects the resource provider.
CustomerSdkStatsTelemetryType.java	Maps TelemetryItem.getName() → spec dimension strings: Request→REQUEST, RemoteDependency→DEPENDENCY, Message→TRACE, Exception→EXCEPTION, Metric→CUSTOM_METRIC, Event→CUSTOM_EVENT, PageView→PAGE_VIEW, Availability→AVAILABILITY. Returns null for internal items (e.g. Statsbeat) to skip counting.
CustomerSdkStatsExceptionCategory.java	Classifies exceptions into low-cardinality reason strings for drop.reason/retry.reason: "Timeout exception", "Network exception", "Storage exception", "Client exception". Traverses the cause chain (depth ≤ 10). Also provides isTimeout() to choose between CLIENT_TIMEOUT and CLIENT_EXCEPTION retry codes.
CustomerSdkStatsTelemetryPipelineListener.java	TelemetryPipelineListener that routes pipeline responses to the accumulator: 200→success, retryable (401/403/408/429/500/502/503/504)→retry, redirect (307/308)→skip, all others→drop. onException categorizes the throwable and records a retry. Includes getReasonPhraseForStatusCode() for common HTTP status codes.

Tests

File	# Tests
CustomerSdkStatsTest.java	10 (accumulation, reset, concurrent increments, telemetry_success split)
CustomerSdkStatsTelemetryTypeTest.java	10 (all 8 mappings + Statsbeat→null + unknown→null)
CustomerSdkStatsExceptionCategoryTest.java	9 (timeout, network, storage, client, null, wrapped exceptions)
CustomerSdkStatsTelemetryPipelineListenerTest.java	9 (success, retry 429/500, drop 402, timeout/network exception, empty skip, redirect skip, reason phrases)
Total	38 tests

Sample

File	Purpose
SimpleWebAppSample.java	Long-running web app with 5 endpoints and 3 test modes (success/drop/retry). In drop/retry modes, a built-in mock ingestion server on port 9090 returns the configured error status and prints all gunzipped payloads to the console, tagged [SDKStats] when applicable.
SimpleWebAppSample-README.md	Step-by-step manual execution guide with env var setup, endpoint table, Kusto query, and expected console output.

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Modified files

File	Change
TelemetryItemExporter.java	Added computeItemCountMetadata() to compute per-type item counts (with success/failure split for REQUEST/DEPENDENCY) before serialization. Added sendWithoutTracking() to send items without triggering recursive customer SDKStats counting. Updated internalSendByBatch() to pass item count maps to the pipeline.
TelemetryPipelineRequest.java	Added itemCountsByType, successItemCountsByType, failureItemCountsByType fields + overloaded public constructor + getters. The original constructor delegates with empty maps.
TelemetryPipelineResponse.java	Made constructor public (was package-private) for test access.
TelemetryPipeline.java	Added overloaded send() accepting item count maps; original send() delegates with empty maps. Passes maps into TelemetryPipelineRequest.
AzureMonitorHelper.java	createTelemetryItemExporter() now accepts CustomerSdkStats, creates a CustomerSdkStatsTelemetryPipelineListener, and wires it into the composite listener chain (alongside DiagnosticTelemetryPipelineListener and LocalStorageTelemetryPipelineListener).
AzureMonitorExporterBuilder.java	Added SDKSTATS_DISABLED_ENV_VAR, SDKSTATS_EXPORT_INTERVAL_ENV_VAR constants. Added createCustomerSdkStats() and startCustomerSdkStats() with a ScheduledExecutorService (daemon thread, default 900s interval) that calls collectAndReset() and sendWithoutTracking().

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Configuration

Environment Variable	Default	Description
APPLICATIONINSIGHTS_SDKSTATS_DISABLED	false	Set to true to disable customer SDKStats entirely.
APPLICATIONINSIGHTS_SDKSTATS_EXPORT_INTERVAL	900 (15 min)	Export interval in seconds.

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Metric details

Metric Name	Dimensions	When counted
Item_Success_Count	computeType, language, version, telemetry_type	HTTP 200 from ingestion
Item_Dropped_Count	computeType, language, version, telemetry_type, drop.code, drop.reason, telemetry_success	Non-retryable HTTP status (e.g. 400, 402, 404)
Item_Retry_Count	computeType, language, version, telemetry_type, retry.code, retry.reason	Retryable HTTP status (401, 403, 408, 429, 500-504) or client exception/timeout

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Validation

• Unit tests: 38/38 passing
• Code formatting: spotlessApply clean
• Compilation: Module compiles successfully
• E2E success mode: Item_Success_Count visible in Azure Monitor customMetrics table with correct dimensions
• E2E drop mode: Item_Dropped_Count visible in mock server console with drop.code=400, drop.reason="Bad request", per-type/per-success breakdown
• E2E retry mode: Mock infrastructure ready (mock server returns 500)

All SDK Contribution checklist:

• The pull request does not introduce [breaking changes]
• CHANGELOG is updated for new features, bug fixes or other significant changes.
• I have read the contribution guidelines.

General Guidelines and Best Practices

• Title of the pull request is clear and informative.
• There are a small number of commits, each of which have an informative message. This means that previously merged commits do not appear in the history of the PR. For more information on cleaning up the commits in your PR, see this page.

Testing Guidelines

• Pull request includes test coverage for the included changes.

[Copilot]

Pull request overview

Adds customer-facing “SDKStats” metric telemetry (success/drop/retry item counts) to the Azure Monitor OpenTelemetry autoconfigure exporter, along with unit tests and a manual sample for validation.

Changes:

• Introduces CustomerSdkStats accumulator + telemetry type/exception categorization + pipeline listener to record per-type success/drop/retry counts.
• Plumbs per-batch item-count metadata through TelemetryItemExporter → TelemetryPipeline/Request, and adds sendWithoutTracking() for exporting SDKStats metrics without recursion.
• Adds unit tests for the new components plus a long-running sample + manual run guide.

Reviewed changes

Copilot reviewed 16 out of 16 changed files in this pull request and generated 14 comments.

Show a summary per file

File	Description
sdk/monitor/azure-monitor-opentelemetry-autoconfigure/src/main/java/com/azure/monitor/opentelemetry/autoconfigure/implementation/statsbeat/CustomerSdkStats.java	New thread-safe counters + collectAndReset() producing Metric TelemetryItems.
sdk/monitor/azure-monitor-opentelemetry-autoconfigure/src/main/java/com/azure/monitor/opentelemetry/autoconfigure/implementation/statsbeat/CustomerSdkStatsExceptionCategory.java	New exception categorization + timeout detection for retry dimensions.
sdk/monitor/azure-monitor-opentelemetry-autoconfigure/src/main/java/com/azure/monitor/opentelemetry/autoconfigure/implementation/statsbeat/CustomerSdkStatsTelemetryType.java	Maps TelemetryItem.getName() to SDKStats telemetry_type dimension values.
sdk/monitor/azure-monitor-opentelemetry-autoconfigure/src/main/java/com/azure/monitor/opentelemetry/autoconfigure/implementation/statsbeat/CustomerSdkStatsTelemetryPipelineListener.java	Observes pipeline responses/exceptions and increments the accumulator.
sdk/monitor/azure-monitor-opentelemetry-autoconfigure/src/main/java/com/azure/monitor/opentelemetry/autoconfigure/implementation/pipeline/TelemetryItemExporter.java	Computes per-batch item-count metadata + adds sendWithoutTracking().
sdk/monitor/azure-monitor-opentelemetry-autoconfigure/src/main/java/com/azure/monitor/opentelemetry/autoconfigure/implementation/pipeline/TelemetryPipeline.java	Adds overload to pass item-count metadata into requests.
sdk/monitor/azure-monitor-opentelemetry-autoconfigure/src/main/java/com/azure/monitor/opentelemetry/autoconfigure/implementation/pipeline/TelemetryPipelineRequest.java	Stores item-count metadata maps and exposes getters.
sdk/monitor/azure-monitor-opentelemetry-autoconfigure/src/main/java/com/azure/monitor/opentelemetry/autoconfigure/implementation/pipeline/TelemetryPipelineResponse.java	Makes constructor public for test construction.
sdk/monitor/azure-monitor-opentelemetry-autoconfigure/src/main/java/com/azure/monitor/opentelemetry/autoconfigure/implementation/utils/AzureMonitorHelper.java	Wires CustomerSdkStatsTelemetryPipelineListener into the exporter listener chain.
sdk/monitor/azure-monitor-opentelemetry-autoconfigure/src/main/java/com/azure/monitor/opentelemetry/autoconfigure/AzureMonitorExporterBuilder.java	Creates/starts periodic export of SDKStats metrics (env-var configurable).
sdk/monitor/azure-monitor-opentelemetry-autoconfigure/src/test/java/com/azure/monitor/opentelemetry/autoconfigure/implementation/statsbeat/CustomerSdkStatsTest.java	Unit tests for accumulation/reset/concurrency.
sdk/monitor/azure-monitor-opentelemetry-autoconfigure/src/test/java/com/azure/monitor/opentelemetry/autoconfigure/implementation/statsbeat/CustomerSdkStatsExceptionCategoryTest.java	Unit tests for exception categorization/timeout detection.
sdk/monitor/azure-monitor-opentelemetry-autoconfigure/src/test/java/com/azure/monitor/opentelemetry/autoconfigure/implementation/statsbeat/CustomerSdkStatsTelemetryTypeTest.java	Unit tests for telemetry type mapping and null/unknown handling.
sdk/monitor/azure-monitor-opentelemetry-autoconfigure/src/test/java/com/azure/monitor/opentelemetry/autoconfigure/implementation/statsbeat/CustomerSdkStatsTelemetryPipelineListenerTest.java	Unit tests for response/exception classification + reason phrases.
sdk/monitor/azure-monitor-opentelemetry-autoconfigure/src/samples/java/com/azure/monitor/opentelemetry/autoconfigure/SimpleWebAppSample.java	Manual sample app + mock ingestion server to validate metric emission.
sdk/monitor/azure-monitor-opentelemetry-autoconfigure/src/samples/java/com/azure/monitor/opentelemetry/autoconfigure/SimpleWebAppSample-README.md	Step-by-step manual guide for the sample.