fix(runner): protect active session runners

src/mgr/kubernetes-runner-job.ts

@@ -1,7 +1,7 @@
 import { spawn } from "node:child_process";
 import { AgentRunError } from "../common/errors.js";
 import { redactJson, redactText } from "../common/redaction.js";
-import { isTerminalCommandState, isTerminalRunStatus, summarizeResourceBundleRef, summarizeSessionRef } from "./store.js";
+import { isLeaseExpired, isTerminalCommandState, isTerminalRunStatus, summarizeResourceBundleRef, summarizeSessionRef } from "./store.js";
 import type { AgentRunStore } from "./store.js";
 import type { ExecutionPolicy, JsonRecord } from "../common/types.js";
 import { stableHash, validateEnvName } from "../common/validation.js";
@@ -133,6 +133,26 @@ export async function createKubernetesRunnerJob(options: { store: AgentRunStore;
   }
   if (isTerminalRunStatus(run.status)) throw new AgentRunError(run.failureKind ?? (run.status === "cancelled" ? "cancelled" : "schema-invalid"), `run ${run.id} is already terminal: ${run.status}`, { httpStatus: 409 });
   if (isTerminalCommandState(command.state) || command.state !== "pending") throw new AgentRunError(command.state === "cancelled" ? "cancelled" : "schema-invalid", `command ${commandId} is not pending: ${command.state}`, { httpStatus: 409 });
+  if (run.claimedBy && !isLeaseExpired(run.leaseExpiresAt)) {
+    const response = {
+      action: "reuse-active-runner",
+      mutation: false,
+      runId: run.id,
+      commandId,
+      runnerId: run.claimedBy,
+      leaseExpiresAt: run.leaseExpiresAt,
+      reason: "fresh-active-runner-lease",
+      valuesPrinted: false,
+    } satisfies JsonRecord;
+    await options.store.appendEvent(run.id, "backend_status", {
+      phase: "runner-job-skipped-active-runner",
+      commandId,
+      runnerId: run.claimedBy,
+      leaseExpiresAt: run.leaseExpiresAt,
+      reason: "fresh-active-runner-lease",
+    });
+    return response;
+  }
   let preCreateRetention: RunnerRetentionSummary | null = null;
   if (options.defaults.retention) {
     preCreateRetention = await enforceRunnerRetentionBeforeCreate({ store: options.store, options: { ...options.defaults.retention, namespace }, incomingRunnerCount: 1 });

src/mgr/runner-retention.ts

@@ -235,16 +235,24 @@ async function podEntry(store: AgentRunStore, item: K8sObject, options: RunnerRe
 async function activityFor(store: AgentRunStore, input: { runId: string | null; commandId: string | null; runnerId: string | null; terminal: boolean; createdAtMs: number; activeHeartbeatMaxAgeMs: number }): Promise<Pick<RunnerResourceEntry, "runId" | "commandId" | "runnerId" | "protectedActive" | "protectedReason" | "candidateKind" | "lastActiveAtMs">> {
   let run: RunRecord | null = null;
   let command: CommandRecord | null = null;
+  let openCommand: CommandRecord | null = null;
   if (input.runId) {
     try { run = await store.getRun(input.runId); } catch { run = null; }
   }
   if (input.commandId) {
     try { command = await store.getCommand(input.commandId); } catch { command = null; }
   }
-  const lastActiveAtMs = Math.max(input.createdAtMs, isoMs(run?.updatedAt), isoMs(command?.updatedAt), isoMs(run?.leaseExpiresAt));
-  if (run && command && !isTerminalRunStatus(run.status) && !isTerminalCommandState(command.state) && !input.terminal) {
+  if (run && !isTerminalRunStatus(run.status) && !input.terminal) {
+    try {
+      openCommand = (await store.listCommands(run.id, 0, 100)).find((item) => !isTerminalCommandState(item.state)) ?? null;
+    } catch {
+      openCommand = null;
+    }
+  }
+  const lastActiveAtMs = Math.max(input.createdAtMs, isoMs(run?.updatedAt), isoMs(command?.updatedAt), isoMs(openCommand?.updatedAt), isoMs(run?.leaseExpiresAt));
+  if (run && !isTerminalRunStatus(run.status) && !input.terminal && (openCommand || (command && !isTerminalCommandState(command.state)))) {
     const freshClaim = input.runnerId && run.claimedBy === input.runnerId && heartbeatFresh(run.leaseExpiresAt, input.activeHeartbeatMaxAgeMs);
-    return { runId: input.runId, commandId: input.commandId, runnerId: input.runnerId, protectedActive: true, protectedReason: freshClaim ? "fresh-active-run" : "nonterminal-runner-resource", candidateKind: "inactive", lastActiveAtMs };
+    return { runId: input.runId, commandId: input.commandId, runnerId: input.runnerId, protectedActive: true, protectedReason: freshClaim ? "fresh-active-run" : openCommand ? "nonterminal-run-open-command" : "nonterminal-runner-resource", candidateKind: "inactive", lastActiveAtMs };
   }
   const candidateKind: CandidateKind = command && isTerminalCommandState(command.state) && !input.terminal ? "idle" : input.terminal || (run !== null && isTerminalRunStatus(run.status)) ? "terminal" : "inactive";
   return { runId: input.runId, commandId: input.commandId, runnerId: input.runnerId, protectedActive: false, protectedReason: null, candidateKind, lastActiveAtMs };