Cherry-pick: LogLevel bug fixes#3524
Merged
RubenCerna2079 merged 5 commits intorelease/2.0from May 7, 2026
Merged
Conversation
RubenCerna2079
changed the title
- Closes issue #3262 The logger for the Startup class is not initialized properly, since this logger is special due to the nature of the Startup class it needs to be continuously updated as DAB initializes. This causes two problems: - Some logs appear even when LogLevel is set to some value that would impede those logs to appear. - Some logs don't appear at all, even when LogLevel is set to a value that should allow them to be logged. - Closes issue #3256 & #3255 The CLI logger still outputs some logs even when the LogLevel is set to `none`. It is expected that if the LogLevel set is `none` or some other level that shouldn't output the `information` level, the logs will not appear. Important Note: These changes currently only allow us to change the LogLevel from the CLI with the `default` namespace in the config file. An task was created to solve this issue: #3451 In order to solve issue #3262: - We removed the LogBuffer from the services inside of `Startup.cs`, this is necessary since we wanted each class to have its own LogBuffer so that we are able to tell from which logger the logs are being outputted. - Then, we also correctly initialized the `Startup` logger by changing the method that it was using to initialize the logger, it now uses `CreateLoggerFactoryForHostedAndNonHostedScenario` which checks if there are any LogLevel namespaces from the config file that can be applicable for the specific logger. It is important to note that there are multiple places where the logs are flushed in order to cover for the cases in which an exception is found and causes DAB to end abruptly, and when we there is an IsLateConfigured scenario. - We also changed the logger for the LogBuffer in all the missing places where it creates logs before the logger is able to properly initialize to add those logs to the LogBuffer and only flush them after the loggers are initialized. In order to solve issue #3256 & #3255: - We changed the CLI so that we add all the logs go to a single global LogBuffer that is created inside the `StartOptions.cs` until it is able to deserialize the RuntimeConfig and find which level to set the `LogLevel` in order to flush all the logs. - This is something that we only want to happen when we use the `dab start` command, which is why we only make this change in the `StartOptions.cs` file, on the function `TryStartEngineWithOptions` inside of `ConfigGenerator.cs`, and a few functions from `Utils.cs` and `ConfigMerger.cs` that are used inside the `TryStartEngine` function. - [ ] Integration Tests - [x] Unit Tests - dab start --LogLevel none - dab start --LogLevel error --------- Co-authored-by: Aniruddh Munde <anmunde@microsoft.com>
## Why make this change? Enables MCP clients (like MCP Inspector, Claude Desktop, VS Code Copilot) to receive real-time log output via MCP `notifications/message`. Related: #3274 (depends on PR #3419) ## What is this change? When `logging/setLevel` is called with a level other than "none", logs are sent to MCP clients as JSON-RPC notifications: ```json { "jsonrpc": "2.0", "method": "notifications/message", "params": { "level": "info", "logger": "Azure.DataApiBuilder.Service.Startup", "data": "Starting Data API builder..." } } ``` ### New files: - `McpLogNotificationWriter.cs` - Writes logs as MCP notifications to stdout - `McpLogger.cs` / `McpLoggerProvider.cs` - ILogger implementation for .NET logging pipeline - `McpLogNotificationTests.cs` - Unit tests (8 tests) ### Modified files: - `Program.cs` - Registers `McpNotificationWriter` and `McpLoggerProvider` for MCP mode - `McpStdioServer.cs` - Enables notifications when `logging/setLevel` is called ## How was this tested? - Unit tests: 6 tests covering level mapping, enable/disable, JSON format - Manual testing with MCP Inspector: verified notifications appear when `logging/setLevel` is sent ## Note This PR targets `dev/anushakolan/set-log-level` (PR #3419) as it depends on the `logging/setLevel` implementation.
RubenCerna2079
force-pushed
the
dev/rubencerna/cherry-pick-fix-loglevel-bugs-3
branch
from
c8019ba to
ee75c86
Compare
RubenCerna2079
requested review from
Alekhya-Polavarapu,
Aniruddh25,
JerryNixon,
aaronburtle,
anushakolan,
rusamant,
sourabh1007,
souvikghosh04,
stuartpa and
vadeveka
as code owners
aaronburtle
approved these changes
May 7, 2026
Contributor
There was a problem hiding this comment.
Pull request overview
This cherry-pick brings in the LogLevel-related fixes (from #3318) to ensure DAB’s Service + CLI + MCP stdio modes respect configured/CLI log levels (including none) and to support dynamic log-level changes and MCP log notifications without corrupting the stdio JSON-RPC channel.
Changes:
- Adds MCP stdio-safe logging by introducing a lock-protected shared stdout writer and an MCP
ILoggerProviderthat emitsnotifications/message. - Refactors startup/config-load logging to buffer early logs and apply runtime-config log level resolution (including logger namespace filtering).
- Updates CLI logging to honor the resolved minimum log level and adjusts/extends unit tests to validate suppression behavior.
Reviewed changes
Copilot reviewed 31 out of 31 changed files in this pull request and generated 6 comments.
Show a summary per file
| File | Description |
|---|---|
| src/Service/Telemetry/DynamicLogLevelProvider.cs | Uses centralized MCP↔.NET log level conversion and supports logger-filtered config log level resolution. |
| src/Service/Startup.cs | Refactors startup log buffering, telemetry logger initialization, and late-config handling; adds a unified flush helper. |
| src/Service/Program.cs | Adds MCP stdio logging setup (provider clearing, dynamic filtering, MCP notification provider wiring). |
| src/Service.Tests/UnitTests/SqlMetadataProviderUnitTests.cs | Stabilizes assertion by waiting for stderr capture and improves failure message. |
| src/Service.Tests/UnitTests/McpStdoutWriterTests.cs | Adds concurrency/disposal tests for the MCP stdout writer. |
| src/Service.Tests/UnitTests/McpLogNotificationTests.cs | Adds tests for MCP log notification writer/provider behavior and JSON framing. |
| src/Service.Tests/UnitTests/DynamicLogLevelProviderTests.cs | Adds concurrency/precedence tests for MCP updates vs CLI override. |
| src/Service.Tests/TestHelper.cs | Ensures runtime config loader has a logger in tests; adds delay/retry helper. |
| src/Service.Tests/Configuration/RuntimeConfigLoaderTests.cs | Updates config loader failure test to use loader logger and new parse-error emission behavior. |
| src/Service.Tests/Configuration/ConfigurationTests.cs | Exposes retry constants for shared use in new delay helper. |
| src/Core/Telemetry/McpLogLevelConverter.cs | Centralizes MCP↔.NET log-level mapping used by multiple components. |
| src/Config/RuntimeConfigLoader.cs | Introduces a shared log buffer for early config-loader logging. |
| src/Config/LogBuffer.cs | Generalizes the prior startup buffer into a reusable buffer that can carry exceptions. |
| src/Config/FileSystemRuntimeConfigLoader.cs | Removes per-instance buffer injection and routes early logs through the shared buffer; adds parse-error emission state. |
| src/Cli/Utils.cs | Adds optional CLI log buffering for early-phase CLI logs; adjusts CLI logger factory creation. |
| src/Cli/Exporter.cs | Updates call-site to the updated config-file precedence helper signature. |
| src/Cli/CustomLoggerProvider.cs | Adds configurable minimum log level and routes Error/Critical to stderr. |
| src/Cli/ConfigMerger.cs | Adds optional CLI buffering for merge logs and errors during dab start. |
| src/Cli/ConfigGenerator.cs | Buffers CLI-phase logs until the effective minimum log level is resolved, then flushes and reconfigures loggers. |
| src/Cli/Commands/StartOptions.cs | Adds a CLI log buffer for dab start and flushes on failure paths. |
| src/Cli.Tests/ValidateConfigTests.cs | Captures stderr (instead of stdout) for validation error messaging; initializes CLI logger factory in env-var test. |
| src/Cli.Tests/UtilsTests.cs | Updates merge-config tests to pass a CLI log buffer. |
| src/Cli.Tests/EnvironmentTests.cs | Adjusts stderr assertions to match new “clean error message” behavior. |
| src/Cli.Tests/EndToEndTests.cs | Adds/adjusts tests for high LogLevel and LogLevel None startup behavior; resets CLI logger factory between tests. |
| src/Cli.Tests/CustomLoggerTests.cs | Splits stdout/stderr expectations and validates Error/Critical go to stderr with correct labels. |
| src/Azure.DataApiBuilder.Mcp/Telemetry/McpLogNotificationWriter.cs | Implements MCP notifications/message emission via shared stdout writer; exposes an enable gate. |
| src/Azure.DataApiBuilder.Mcp/Telemetry/McpLoggerProvider.cs | Adds an MCP ILoggerProvider that caches category loggers and enforces disposal semantics. |
| src/Azure.DataApiBuilder.Mcp/Telemetry/McpLogger.cs | Implements an MCP ILogger that emits notifications and appends exception details. |
| src/Azure.DataApiBuilder.Mcp/Model/McpStdioJsonRpcErrorCodes.cs | Centralizes JSON-RPC version constant. |
| src/Azure.DataApiBuilder.Mcp/Core/McpStdoutWriter.cs | Adds a process-wide, lock-protected stdout owner to prevent JSON-RPC frame interleaving. |
| src/Azure.DataApiBuilder.Mcp/Core/McpStdioServer.cs | Routes JSON-RPC responses through the shared stdout writer and toggles MCP notification gating on logging/setLevel. |
Aniruddh25
approved these changes
May 7, 2026
github-project-automation
Bot
moved this from Review In Progress
to Done
in Data API builder
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.This suggestion is invalid because no changes were made to the code.Suggestions cannot be applied while the pull request is closed.Suggestions cannot be applied while viewing a subset of changes.Only one suggestion per line can be applied in a batch.Add this suggestion to a batch that can be applied as a single commit.Applying suggestions on deleted lines is not supported.You must change the existing code in this line in order to create a valid suggestion.Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be applied on multi-line comments.Suggestions cannot be applied while the pull request is queued to merge.Suggestion cannot be applied right now. Please check back later.
Why make this change?
This change cherry-picks the PRs that fix the LogLevel bugs
What is this change?
nonebug #3318How was this tested?
Existing tests in cherry-pick cover new changes.
Sample Request(s)
N/A