refactor: extract MCP client initialization logic into LifecyleInitializer #370
+786
−187
Conversation
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
…lizer - Create new LifecyleInitializer class to handle protocol initialization phase - Move initialization logic from McpAsyncClient to dedicated initializer - Add javadocs for MCP initialization process - Implement protocol version negotiation and capability exchange - Add exception handling for transport session recovery - Include test suite for LifecyleInitializer - Simplify McpAsyncClient by delegating initialization responsibilities This refactoring improves separation of concerns and makes the initialization process more maintainable and testable. Signed-off-by: Christian Tzolov <[email protected]>
tzolov
force-pushed
the
extract-client-initialization-logic
branch
from
85545f4 to
ef140fc
Compare
chemicL
requested changes
Jul 7, 2025
| * the initialized notification</li> | ||
| * </ul> | ||
| */ | ||
| public class LifecyleInitializer { |
There was a problem hiding this comment.
Suggested change
| public class LifecyleInitializer { | |
| class LifecyleInitializer { |
| * clients and servers. | ||
| */ | ||
| private final Function<ContextView, McpClientSession> sessionSupplier; | ||
| private LifecyleInitializer initializer; |
There was a problem hiding this comment.
Suggested change
| private LifecyleInitializer initializer; | |
| private final LifecyleInitializer initializer; |
| * @param operation The operation to execute when the client is initialized | ||
| * @return A Mono that completes with the result of the operation | ||
| */ | ||
| public <T> Mono<T> withIntitialization(String actionName, Function<Initialization, Mono<T>> operation) { |
There was a problem hiding this comment.
Suggested change
| public <T> Mono<T> withIntitialization(String actionName, Function<Initialization, Mono<T>> operation) { | |
| public <T> Mono<T> ensureInitialized(String actionName, Function<Initialization, Mono<T>> operation) { |
There was a problem hiding this comment.
I don't think ensureInitialized reflects the functionality It performs. The withIntitialization implies some additional functionality is applied. The ensure implies a validation check.
| } | ||
|
|
||
| @Test | ||
| void shouldTimeoutOnSlowInitialization() { |
There was a problem hiding this comment.
How long does this test take? Can we use VirtualTimeScheduler for it?
| return mockSession; | ||
| }); | ||
|
|
||
| // Start multiple concurrent initializations |
There was a problem hiding this comment.
Did you intend to make them parallel? You could do that with subscribeOn and using a parallel Scheduler
| // re-initialization | ||
| // We need to wait a bit for the async re-initialization to start | ||
| try { | ||
| Thread.sleep(10); // Small delay to allow async processing |
There was a problem hiding this comment.
Every time we use sleep we almost certainly introduce flakiness into the test suite, please let's avoid it.
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.
Refactor MCP client initialization logic by extracting it from
McpAsyncClientinto a dedicatedLifecyleInitializerclass.This improves separation of concerns, maintainability, and testability of the initialization process.
Motivation and Context
The
McpAsyncClientclass was becoming too complex with initialization logic mixed in with client operations.This refactoring addresses several issues:
McpAsyncClientinterface is now cleaner and focused on its primary responsibilitiesHow Has This Been Tested?
LifecyleInitializerTests.javacovering:McpAsyncClienttests continue to pass, ensuring backward compatibilityBreaking Changes
No breaking changes - This is an internal refactoring that maintains full API compatibility. All public methods of
McpAsyncClientremain unchanged and behave identically.Types of changes
Note: While marked as potentially breaking, this is actually a non-breaking internal refactoring.
Checklist
Additional context
Implementation Notes:
LifecyleInitializerfollows the MCP specification for initialization phase requirementsMcpTransportSessionNotFoundExceptionwith automatic re-initializationFiles Changed:
LifecyleInitializer.java(348 lines) - Core initialization logicLifecyleInitializerTests.java(403 lines) - Comprehensive test suiteMcpAsyncClient.java- Simplified by delegating toLifecyleInitializer