[enhancement] proxy: filter CNs that are not in working state.

[volgariver6]

User description

What type of PR is this?

• API-change
• BUG
• Improvement
• Documentation
• Feature
• Test and CI
• Code Refactoring

Which issue(s) this PR fixes:

issue #16357

What this PR does / why we need it:

1. filter CNs that are not in working state.
2. add some logs for migration

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PR Type

Enhancement, Other

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Description

• Added logging for connection migration from server, including details such as server address, tenant, username, connection ID, database, and number of prepared statements.
• Filtered out CN services that are not in a working state in the collectTunnels function.
• Added logging for building new server connections, including previous server address and errors if connection building fails.

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Changes walkthrough 📝

Relevant files

Enhancement

conn_migration.go Add logging for connection migration details.                        pkg/proxy/conn_migration.go Added logging for connection migration from server. Included details such as server address, tenant, username, connection ID, database, and number of prepared statements. +9/-0      rebalancer.go Filter out non-working CN services in rebalancer.                pkg/proxy/rebalancer.go Filtered out CN services that are not in a working state. Updated the collectTunnels function to include this filtering. +6/-0      tunnel.go Add logging for new server connection attempts.                    pkg/proxy/tunnel.go Added logging for building new server connections. Logged previous server address and errors if connection building fails. +7/-1

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💡 PR-Agent usage:
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PR Review 🔍

⏱️ Estimated effort to review [1-5]	2, because the changes are straightforward and localized to specific functions within the codebase. The modifications include adding logging statements and filtering logic, which are not complex but require validation to ensure they are correctly implemented and do not affect existing functionalities.
🧪 Relevant tests	No
⚡ Possible issues	Logging Level: Ensure that the logging level (Info, Error) is appropriate for the scenarios described. Over-logging at a high level can clutter log files and obscure important information.
	Error Handling: In the new logging for error scenarios, ensure that the error handling is not changed or impacted negatively by the new log statements.
🔒 Security concerns	No

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PR Code Suggestions ✨

Category	Suggestion	Score
Security	Mask or omit sensitive information in log statements to enhance security To avoid potential logging of sensitive information, consider masking or omitting sensitive data such as username and tenant in the log statement. pkg/proxy/conn_migration.go [58-64] c.log.Info("connection migrate from server", zap.String("server address", addr), - zap.String("tenant", string(c.clientInfo.Tenant)), - zap.String("username", c.clientInfo.username), + zap.String("tenant", "****"), + zap.String("username", "****"), zap.Uint32("conn ID", c.connID), zap.String("DB", r.DB), zap.Int("prepare stmt num", len(r.PrepareStmts)), ) Suggestion importance[1-10]: 9 Why: The suggestion correctly identifies a potential security risk by logging sensitive information and provides a solution to mask this data. This is crucial for protecting user privacy and security.	9
Possible bug	Add a nil check for t.mu.serverConn to prevent potential nil pointer dereference To avoid potential nil pointer dereference, add a nil check for t.mu.serverConn before accessing its RemoteAddr method. pkg/proxy/tunnel.go [401-402] -prevAddr := t.mu.serverConn.RemoteAddr().String() +var prevAddr string +if t.mu.serverConn != nil { + prevAddr = t.mu.serverConn.RemoteAddr().String() +} t.logger.Info("build connection with new server", zap.String("prev addr", prevAddr)) Suggestion importance[1-10]: 8 Why: Adding a nil check is a crucial improvement as it prevents a potential runtime error that could crash the application. This suggestion addresses a possible bug.	8
Maintainability	Refactor repeated condition checks into a helper function to improve maintainability Instead of repeating the same condition to check WorkState, consider refactoring the code to use a helper function that encapsulates this logic, improving maintainability. pkg/proxy/rebalancer.go [168-170] -if s.WorkState != metadata.WorkState_Working { +if !isServiceWorking(s) { return } +... + +func isServiceWorking(s *metadata.CNService) bool { + return s.WorkState == metadata.WorkState_Working +} + Suggestion importance[1-10]: 7 Why: The suggestion to refactor repeated code into a helper function is valid and improves code maintainability. However, it's a moderate improvement as it mainly affects code readability and structure.	7
Enhancement	Combine error message and context into a single log statement for better readability To enhance the readability and consistency of the error logging, consider combining the error message and context into a single log statement. pkg/proxy/tunnel.go [405-408] -t.logger.Error("failed to build connection with new server", - zap.String("prev addr", prevAddr), - zap.Error(err), -) +t.logger.Error("failed to build connection with new server", + zap.String("prev addr", prevAddr), + zap.Error(err)) Suggestion importance[1-10]: 5 Why: The suggestion improves the readability of the log statements, but the impact is relatively minor as it mainly affects the style and consistency of the logging.	5