feature: benchmark cli

[WangzJi]

• I have read the CONTRIBUTING.md guidelines.
• I have registered the PR changes.

Ⅰ. Describe what this PR did

Closes: #7646
Add a new seata-benchmark-cli module under test-suite for stress testing Seata transaction modes.

Features:

• Support for AT, TCC, and SAGA transaction modes
• Dual execution modes:
  • Empty mode (--branches 0): Measures pure Seata protocol overhead without database operations
  • Real mode (--branches N): Executes actual distributed transactions with database operations
• Configurable TPS (Transactions Per Second) rate limiting
• Multi-threaded workload generation with configurable thread pool
• Fault injection with configurable rollback percentage
• Window-based progress reporting (every 10 seconds)
• Performance metrics collection: latency percentiles (P50/P95/P99), success rate, TPS
• CSV export for post-analysis
• Warmup support: exclude initial ramp-up period from final statistics
• YAML configuration file support with priority: CLI args > env var > system property > classpath

Module Structure:

test-suite/seata-benchmark-cli/
├── src/main/java/org/apache/seata/benchmark/
│   ├── BenchmarkApplication.java       # Main entry with picocli CLI
│   ├── BenchmarkConstants.java         # Constants definition
│   ├── config/                         # Configuration classes
│   ├── executor/                       # Transaction executors (AT/TCC/SAGA)
│   ├── model/                          # Data models (metrics, records)
│   ├── monitor/                        # Metrics collection
│   ├── saga/                           # SAGA mode services
│   └── util/                           # Utility classes
└── src/main/resources/
    ├── seata/saga/statelang/           # SAGA state machine definitions
    └── *.conf                          # Seata configuration

Ⅱ. Does this pull request fix one issue?

No, this is a new feature.

Ⅲ. Why don't you add test cases (unit test/integration test)?

This is a benchmark/stress testing tool. The primary validation is manual testing against a running Seata Server. Integration tests would require a full Seata Server setup which is better suited for the existing integration test infrastructure.

Ⅳ. Describe how to verify it

1. Build the module:

   cd test-suite/seata-benchmark-cli
   ../../mvnw clean package

2. Start Seata Server (ensure it's running on 127.0.0.1:8091)

3. Run benchmark (empty mode - no database required):

   java -jar target/seata-benchmark-cli.jar \
     --server 127.0.0.1:8091 \
     --mode AT \
     --tps 100 \
     --duration 60

4. Run benchmark (real mode - requires Docker):

   java -jar target/seata-benchmark-cli.jar \
     --server 127.0.0.1:8091 \
     --mode AT \
     --tps 100 \
     --duration 60 \
     --branches 3

5. Verify the output shows progress every 10 seconds and final report with metrics.

Ⅴ. Special notes for reviews

1. Latency Sampling: To prevent OOM on large-scale tests, latencies are sampled (max 500K samples) - inspired by Kafka ProducerPerformance.

2. Empty vs Real Mode: Empty mode (--branches 0) is useful for measuring pure Seata Server capacity without database overhead.

3. SAGA Implementation: Real SAGA mode uses Seata's state machine engine with predefined state machine definitions in src/main/resources/seata/saga/statelang/.

4. Dependencies: The module uses:

   • picocli for CLI argument parsing
   • snakeyaml for YAML configuration
   • testcontainers for MySQL in real mode
   • Seata's existing infrastructure (TM, RM, Saga engine)

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 71.17%. Comparing base (340aa3c) to head (447b8e4).

Additional details and impacted files

@@             Coverage Diff              @@
##                2.x    #7865      +/-   ##
============================================
- Coverage     71.20%   71.17%   -0.04%     
+ Complexity      797      785      -12     
============================================
  Files          1300     1300              
  Lines         49620    49620              
  Branches       5874     5874              
============================================
- Hits          35331    35315      -16     
- Misses        11371    11387      +16     
  Partials       2918     2918              

see 11 files with indirect coverage changes

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