v0.2.1

This release reworks multi-endpoint handling and adds request-level failover for unary writes/deletes.

Highlights

Added

• GreptimeClientOptions.Failover (FailoverOptions) — request-level failover for multi-endpoint clients. Unary write/delete requests are retried against another endpoint after safe transient transport failures or retryable GreptimeDB server status codes. Tunables: Enabled, MaxAttempts, ConsecutiveFailuresBeforeEjection, BaseEjectionDelay, MaxEjectionDelay. Endpoints that fail repeatedly are ejected from selection with exponential backoff and reinstated automatically.
• GreptimeServerException — surfaces the GreptimeDB server status code from the response trailer, so callers can distinguish retryable from terminal server errors.

Changed

• Replaced the Grpc.Net.Client.Balancer round-robin channel with a client-side endpoint selector that performs request-level failover. Only unary writes/deletes are replayed; client-side write deadlines are not replayed because the outcome is ambiguous. Streaming and bulk writers are not replayed automatically — their final transport outcome updates endpoint health so the next writer picks a healthy endpoint. LoadBalancing (Random / RoundRobin) still selects the per-request endpoint.
• Duplicate entries in Endpoints are now rejected during validation.

See CHANGELOG.md for details.

Notable PRs

• Endpoint failover for unary writes by @killme2008 in #66

Dependency updates

• Bump the testing group with 1 update by @dependabot[bot] in #43
• Bump Microsoft.Extensions.Configuration.Abstractions and 4 others by @dependabot[bot] in #42
• chore(deps): bump proto from 26a50f4 to 0de5437 by @dependabot[bot] in #41
• Bump the microsoft group with 6 updates by @dependabot[bot] in #48
• Bump Apache.Arrow and Apache.Arrow.Flight by @dependabot[bot] in #53
• Bump the testing group with 1 update by @dependabot[bot] in #51
• Bump the grpc group with 1 update by @dependabot[bot] in #50
• chore(deps): bump proto from 0de5437 to a107830 by @dependabot[bot] in #49
• chore(deps): bump proto from a107830 to 5e35831 by @dependabot[bot] in #63
• Bump the microsoft group with 6 updates by @dependabot[bot] in #64
• Bump the grpc group with 2 updates by @dependabot[bot] in #65
• Bump the testing group with 3 updates by @dependabot[bot] in #61

Full Changelog: v0.2.0...v0.2.1