Add Telemetry to Application Name by aaronburtle · Pull Request #3683 · Azure/data-api-builder

aaronburtle · 2026-06-26T01:21:28Z

Why make this change?

DAB ships as an open-source container customers run anywhere, so we have little visibility into how it is configured or which features are used. This change encodes an anonymous usage fingerprint into the connection's Application Name, which the database side already records (e.g. sys.dm_exec_sessions.program_name), giving aggregate insight with no new endpoints, no network calls, and no per-customer data.

What is this change?

Embeds an anonymous, decodable usage-telemetry token into the Application Name of the connection strings DAB uses for SQL Server / Azure SQL, DWSQL, and PostgreSQL.

Format: dab_oss_<version>+<context>|<runtime>|<entity>+ a version plus three flag sections (Context = 4, Runtime = 20, Entity = 14). Values use 0/1 (off/on), M (missing section), X (not applicable at pool open), ? (not yet modeled).
Pooling-safe (Model A): only fields known when a pooled connection opens are encoded (the data-source engine as Source); per-request facets (protocol/object/role) are X so the connection-pool key, and therefore pool count, is unchanged.
Where it's injected: at config load (RuntimeConfigLoader) and on the hosted/late-config POST /configuration paths (RuntimeConfigProvider.Initialize). Embedding is idempotent (skips if the dab_oss_ marker is already present).
Multi-database: the global runtime + merged entity fingerprint is encoded at every pool (the token has no correlation id, so any single sampled connection reflects the whole deployment); Source still varies per pool.
Opt-out: DAB_TELEMETRY_APPNAME_OPT_OUT=1 reduces the value to version-only.
Hosted label: an existing DAB_APP_NAME_ENV value (e.g. dab_hosted) is preserved as a comma prefix and never suppresses the token.
CLI: new offline dab appname command to encode (--config) or decode (--decode) a token; -o/--output writes to a file.
Logging: the computed token (never the connection string) is logged at Debug via a bounded, drop-oldest LogBuffer flushed once the logger is available.
Scope: MySQL and Cosmos DB connection strings are left unchanged.
Design doc: docs/design/application-name-telemetry.md.

How was this tested?

Integration Tests
Unit Tests

Added encoder/decoder unit tests (token shape, every flag/section, Source + auth-provider maps, opt-out, host-label prefix, truncation-tolerant decode), connection-string injection tests for MSSQL/DWSQL/PostgreSQL (incl. user-supplied Application Name prefix) and no-op cases for MySQL/Cosmos, multi-database and hosted/late-config (/configuration + /configuration/v2) tests, an idempotency test, LogBuffer bound/flush tests, and CLI encode/decode/error/opt-out tests.

Sample Request(s)

Encode the token for a config (offline, no DB connection):

dab appname --config dab-config.json
# dab_oss_2.0.0+XXXX|110000M1M000MMMMMWMM|100?111001110?+

Decode a token back to a human-readable legend:

dab appname --decode "dab_oss_2.0.0+XXSX|110000M1M000MMMMMWMM|100?111001110?+"

Observe it on the SQL Server side:

SELECT program_name
FROM sys.dm_exec_sessions
WHERE program_name LIKE 'dab_oss%' OR program_name LIKE '%,dab_oss%';

Copilot

Pull request overview

Adds anonymous, decodable usage telemetry by embedding a DAB-specific token into database connection strings’ Application Name for SQL Server/Azure SQL, DWSQL, and PostgreSQL, with an offline CLI encoder/decoder and buffered debug logging suitable for hosted/late-config and hot-reload scenarios.

Changes:

Introduces ApplicationNameTelemetry encoder/decoder and injects telemetry-bearing Application Name into MSSQL/DWSQL/PostgreSQL connection strings during config load and hosted/late-config initialization.
Makes telemetry embedding pool-safe/idempotent, adds bounded LogBuffer, and flushes buffered logs on hot reload and hosted initialization paths.
Adds new dab appname CLI command (encode/decode) plus extensive unit/E2E/integration test coverage for telemetry shape, injection behavior, multi-DB merge behavior, opt-out, and log buffering.

Reviewed changes

Copilot reviewed 16 out of 16 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
src/Service.Tests/UnitTests/RuntimeConfigLoaderJsonDeserializerTests.cs	Updates test to new MSSQL-specific Application Name injection helper.
src/Service.Tests/UnitTests/LogBufferTests.cs	Adds unit tests for bounded buffering and flush/drain behavior.
src/Service.Tests/UnitTests/ApplicationNameTelemetryTests.cs	Adds unit tests for telemetry encoding/decoding, opt-out, host label prefixing, and multi-DB live-vs-default encoding.
src/Service.Tests/Configuration/RuntimeConfigLoaderTests.cs	Adds regression tests for multi-DB telemetry merge correctness, idempotency, and log buffer flushing.
src/Service.Tests/Configuration/ConfigurationTests.cs	Updates/extends configuration tests for telemetry-bearing Application Name across MSSQL/Postgres/DWSQL and hosted/late-config scenarios.
src/Product/ProductInfo.cs	Introduces a stable `dab_oss_` marker constant and uses it to build the DAB user agent string.
src/Core/Configurations/RuntimeConfigProvider.cs	Ensures telemetry is embedded and logs flushed during hosted/late-config initialization for all data sources.
src/Config/Telemetry/ApplicationNameTelemetry.cs	Implements telemetry token encoding/decoding and environment-driven opt-out/label prefixing.
src/Config/RuntimeConfigLoader.cs	Reworks post-parse connection string processing to support multi-DB, idempotent telemetry injection, and override behavior.
src/Config/ObjectModel/RuntimeConfig.cs	Ensures child config loads skip Application Name injection so the merged/root config injects once globally.
src/Config/LogBuffer.cs	Adds a max buffer size and drop-oldest behavior to prevent unbounded growth.
src/Config/FileSystemRuntimeConfigLoader.cs	Flushes buffered logs on hot reload; uses base loader flushing via overridden logger property.
src/Config/DeserializationVariableReplacementSettings.cs	Adds `SkipApplicationNameInjection` flag to coordinate multi-DB child/root injection behavior.
src/Cli/Program.cs	Registers new `appname` command options.
src/Cli/Commands/AppNameOptions.cs	Adds `dab appname` command (encode from config without validation; decode tolerant of truncation; optional file output).
src/Cli.Tests/EndToEndTests.cs	Adds E2E coverage for `appname` encode/decode/output behaviors and updates Application Name assertions for telemetry.

…b.com/Azure/data-api-builder into dev/aaronburtle/Telemetry-in-app-name

Aniruddh25 · 2026-07-09T00:00:10Z

+
+## Summary
+
+Data API builder (DAB) embeds a compact, anonymous **usage-telemetry token** into the `Application Name` property of the connection strings it uses to reach SQL Server, Azure SQL, Azure SQL Data Warehouse (DWSQL), and PostgreSQL. Because `Application Name` is surfaced on the database side (for example in `sys.dm_exec_sessions.program_name`), this lets the team understand &mdash; **in aggregate and without any per-customer identifiers** &mdash; which DAB version is running and which features are enabled, using telemetry the database already collects.


Why not MySQL? And why PostgreSQL? Is sys.dm_exec_sessions.program_name supported on PostgreSQL

Aniruddh25 · 2026-07-09T18:40:35Z

+
+### Hosted label (`DAB_APP_NAME_ENV`)
+
+When `DAB_APP_NAME_ENV` is set (DAB's hosted offering sets it to `dab_hosted`), its value is preserved as a **comma prefix**: `dab_hosted,dab_oss_<version>+...+`. Telemetry is always computed from the product version, so the host label **never suppresses** the token and the `dab_oss_` marker stays intact for decoding.


in the hosted case, the appname should be dab_hosted_<version>+...+ It should not include dab_oss_ marker.

Aniruddh25 · 2026-07-09T20:39:58Z


+        // Idempotency guard: if DAB telemetry was already embedded into the Application Name (e.g. by
+        // the loader's post-processing), do not append it again — that would duplicate the payload.
+        if (connectionStringBuilder.ApplicationName?.Contains(ProductInfo.DAB_USER_AGENT_MARKER, StringComparison.Ordinal) == true)


For the hosted scenario, the embedded application name should be dab_hosted_. dab_oss_ should not be present in the embedded application name for that case. The contains check here should verify if is present, to not append again. This is because is the common marker between oss and hosted scenarios.

Aniruddh25 · 2026-07-09T20:45:01Z


+        // Idempotency guard: if DAB telemetry was already embedded into the Application Name (e.g. by
+        // the loader's post-processing), do not append it again — that would duplicate the payload.
+        if (connectionStringBuilder.ApplicationName?.Contains(ProductInfo.DAB_USER_AGENT_MARKER, StringComparison.Ordinal) == true)


same as above: check should verify

Aniruddh25 · 2026-07-09T20:51:43Z

+    /// Options for the <c>appname</c> command, which encodes the DAB telemetry Application Name
+    /// from a config file, or decodes a telemetry Application Name into a human-readable description.
+    /// </summary>
+    [Verb("appname", isDefault: false, HelpText = "Show or decode the DAB telemetry 'Application Name' embedded in SQL connections.", Hidden = false)]


Suggested change

[Verb("appname", isDefault: false, HelpText = "Show or decode the DAB telemetry 'Application Name' embedded in SQL connections.", Hidden = false)]

[Verb("appname", isDefault: false, HelpText = "Show or decode the DAB telemetry 'Application Name' embedded in datasource connections.", Hidden = false)]

Aniruddh25 · 2026-07-09T20:55:42Z

+        string entity = EncodeSection(_entitySettings, inputs);
+
+        return new StringBuilder()
+            .Append(ProductInfo.DAB_USER_AGENT)


should be dab_hosted for hosted scenario.

Aniruddh25 · 2026-07-09T20:57:18Z

+    public static string BuildApplicationNameSegment(RuntimeConfig config, DataSource? liveDataSource)
+    {
+        string telemetry = IsOptedOut()
+            ? ProductInfo.DAB_USER_AGENT


if hosted, this should be dab_hosted, not dab_oss

aaronburtle added 7 commits June 25, 2026 05:37

add telemetry to app name

ce2bd0f

fill in gaps

88673bb

fix hosted coverage better testing

af161e1

improve hot reload logging

968b06e

idempotent telemetry in hosted scenario

51980d0

flush in hosted scenario

47fa0aa

bounded logbuffer, env var isolation in test

b467188

Copilot AI review requested due to automatic review settings June 26, 2026 01:21

aaronburtle requested review from Alekhya-Polavarapu, Aniruddh25, JerryNixon, RubenCerna2079, anushakolan, rusamant, sourabh1007, souvikghosh04, stuartpa and vadeveka as code owners June 26, 2026 01:21

Copilot started reviewing on behalf of aaronburtle June 26, 2026 01:21 View session

Copilot AI reviewed Jun 26, 2026

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Comment thread src/Config/Telemetry/ApplicationNameTelemetry.cs

Comment thread src/Config/LogBuffer.cs

aaronburtle and others added 3 commits June 26, 2026 01:52

Merge branch 'main' into dev/aaronburtle/Telemetry-in-app-name

3ba9f00

doc update, format fix

2ac6628

Merge branch 'dev/aaronburtle/Telemetry-in-app-name' of https://githu…

8e098b8

…b.com/Azure/data-api-builder into dev/aaronburtle/Telemetry-in-app-name

aaronburtle changed the title ~~Dev/aaronburtle/telemetry in app name~~ Add Telemetry to app-name Jun 26, 2026

aaronburtle changed the title ~~Add Telemetry to app-name~~ Add Telemetry to Application Name Jun 26, 2026

aaronburtle self-assigned this Jun 26, 2026

aaronburtle added 2.1 telemetry feature requests/ bug reports related to telemetry labels Jun 26, 2026

aaronburtle added this to Data API builder Jun 26, 2026

github-project-automation Bot moved this to Todo in Data API builder Jun 26, 2026

aaronburtle moved this from Todo to Review In Progress in Data API builder Jun 26, 2026

aaronburtle added this to the June 2026 milestone Jun 26, 2026

aaronburtle added the assign-for-review label Jun 26, 2026

github-actions Bot assigned Aniruddh25 and RubenCerna2079 Jun 26, 2026

github-actions Bot removed the assign-for-review label Jun 26, 2026

Aniruddh25 reviewed Jul 9, 2026

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Aniruddh25 modified the milestones: June 2026, July 2026 Jul 9, 2026

Aniruddh25 reviewed Jul 9, 2026

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Add Telemetry to Application Name#3683

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Aniruddh25 Jul 9, 2026 •

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		## Summary

		Data API builder (DAB) embeds a compact, anonymous usage-telemetry token into the `Application Name` property of the connection strings it uses to reach SQL Server, Azure SQL, Azure SQL Data Warehouse (DWSQL), and PostgreSQL. Because `Application Name` is surfaced on the database side (for example in `sys.dm_exec_sessions.program_name`), this lets the team understand — in aggregate and without any per-customer identifiers — which DAB version is running and which features are enabled, using telemetry the database already collects.


		### Hosted label (`DAB_APP_NAME_ENV`)

		When `DAB_APP_NAME_ENV` is set (DAB's hosted offering sets it to `dab_hosted`), its value is preserved as a comma prefix: `dab_hosted,dab_oss_<version>+...+`. Telemetry is always computed from the product version, so the host label never suppresses the token and the `dab_oss_` marker stays intact for decoding.

	[Verb("appname", isDefault: false, HelpText = "Show or decode the DAB telemetry 'Application Name' embedded in SQL connections.", Hidden = false)]
	[Verb("appname", isDefault: false, HelpText = "Show or decode the DAB telemetry 'Application Name' embedded in datasource connections.", Hidden = false)]

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aaronburtle commented Jun 26, 2026

Why make this change?

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How was this tested?

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