feat(interaction-store): add optional client gRPC keepalive

[kanhaiya-garg-meesho]

Context:

The interaction-store gRPC client dials with no client keepalive. When a connection silently black-holes (e.g. a stale conntrack entry / dead TCP path with no FIN or RST), the gRPC channel stays READY and the client keeps writing onto a dead connection — failures persist until a per-RPC deadline fires or the kernel's TCP retransmit logic gives up (on the order of minutes). Latency-sensitive consumers (e.g. recently-viewed catalog recommendations on a tight per-call budget) have no way to detect and recycle such a connection quickly. This change adds an opt-in keepalive so consumers that need it can enable it via config, without affecting anyone else.

Describe your changes:

• Config gains three optional fields: KeepaliveTimeMs, KeepaliveTimeoutMs, KeepalivePermitWithoutStream.
• getGRPCConnections now assembles its dial options via a new dialOptions(Config) helper, which appends grpc.WithKeepaliveParams(...) only when KeepaliveTimeMs > 0 (derived by the pure helper keepaliveParamsFromConfig).
• Fully backward-compatible / opt-in: with the fields unset (zero value), the dial-option set is byte-for-byte identical to before, so every existing consumer is unaffected. The exported NewClientV1 signature is unchanged, and there is no go.mod / go.sum change (keepalive ships with google.golang.org/grpc).
• Documented on the Config fields: callers must keep KeepaliveTimeMs at or above the server's keepalive EnforcementPolicy.MinTime, or the server will close the connection with GOAWAY "too_many_pings".

Testing:

• New grpc_test.go unit tests (table-driven, testify): the opt-in gate (disabled when KeepaliveTimeMs <= 0, including negative), millisecond→time.Duration mapping, PermitWithoutStream handling, and a backward-compatibility assertion that the default dial-option set is unchanged and that enabling keepalive appends exactly one option.
• Extended TestNewClientV1 with a keepalive-enabled construction case.
• gofmt -l clean, go build, go vet, and go test -race ./pkg/interaction-store/... all green; existing suite unaffected.
• Behavioural validation — that keepalive actually emits PINGs and behaves correctly against a server's EnforcementPolicy (the too_many_pings GOAWAY edge) — is exercised separately in the consuming service's integration environment against the real server's enforcement policy. It is intentionally out of scope for these SDK unit tests, which cover the configuration/option-assembly logic only.

Monitoring:

No new metrics are emitted by the SDK. Consumers that enable keepalive should watch their existing gRPC connection-state / error signals for too_many_pings GOAWAYs after rollout, which would indicate the configured KeepaliveTimeMs is below the server's MinTime. The feature is inert unless explicitly configured.

Rollback plan

Opt-in and config-driven at the consumer: unset / zero the keepalive fields to return to the prior no-keepalive behaviour with no code change. Reverting this PR is equally safe — it only adds optional Config fields and one conditional dial option.

Checklist before requesting a review

• I have reviewed my own changes?
• Relevant or critical functionality is covered by tests?
• Monitoring needs have been evaluated?
• Any necessary documentation updates have been considered?

📂 Modules Affected

• Other: go-sdk (interaction-store client)

✅ Type of Change

• Feature addition

📊 Benchmark / Metrics (if applicable)

N/A — no hot-path or performance change. With keepalive disabled (the default) the dial options are identical to before; when enabled it adds background HTTP/2 PINGs at the configured interval.

🤖 Generated with Claude Code

[m-agentic-review]

🤖 Code Review — PR #378

Language: Go  |  Files reviewed: 4

Severity		Count
SUGGESTION	💡	1
WARNING	⚠️	3

[m-agentic-review]

🟢 LOW — safe to fast-track · confidence 0.92

This SDK change only adds optional gRPC keepalive settings that stay off unless a caller explicitly sets them, so existing services keep the same connection behavior after merge. Tests in grpc_test.go confirm the default dial path still builds exactly two options (transport + round-robin) with no keepalive, and NewClientV1 is unchanged. Cleared: no breaking API, schema, or dependency changes.

Top risks

• go-sdk/pkg/interaction-store/grpc.go#dialOptions — keepalive is appended only when KeepaliveTimeMs > 0; default zero config leaves dial options identical to before

Check before approving

• Keepalive is inactive at merge — only services that opt in via Config will send PINGs
• If a consumer enables keepalive, confirm KeepaliveTimeMs meets the server's minimum interval to avoid too_many_pings disconnects

8 tool(s) ran · DRS agentic v2 · #378

[m-agentic-review]

🤖 Code Review — PR #378

Language: Go  |  Files reviewed: 4

Severity		Count
SUGGESTION	💡	1
WARNING	⚠️	3

[turbo-turtle-github]

FTR:AI-BLITZ

AI Blitz check

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Failing checks:

❌ Unit-test coverage pipeline — pipeline did not run
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[kanhaiya-garg-meesho]

Closing this PR — the change is being raised in our internal source-of-truth repository instead (the public SDK is published from there). Apologies for the noise here.