test: add chaos-mesh/toxiproxy based network fault injection for integration tests

[tinswzy]

Background

Woodpecker heavily depends on object storage (e.g., S3/MinIO) and network stability for WAL write/read paths.
However, current integration tests assume a stable network and do not cover degraded scenarios such as latency spikes, jitter, or transient disconnections.

In real-world deployments (multi-AZ / cloud environments), network instability is common and may lead to:

• increased write latency
• retry amplification
• LAC progression delay
• read unavailability under certain conditions

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Proposal

Introduce chaos-based network fault injection into integration tests using:

• :contentReference[oaicite:0]{index=0} (for local / docker-compose / CI)
• :contentReference[oaicite:1]{index=1} (for k8s-based testing)

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Scope

1. Toxiproxy-based tests (local / CI)

• Add toxiproxy container into integration test environment
• Route object storage traffic through proxy
• Inject faults:
  • latency (e.g. 200ms / 500ms)
  • jitter (e.g. ±100ms)
  • connection toggle (simulate transient outage)

Example:

toxiproxy-cli toxic add minio -t latency -a latency=500 -a jitter=100
toxiproxy-cli toggle minio