fleetd #176: fail-fast + safe UNKNOWN refinement in the spawn-readiness gate #233

Merged
ltms merged 2 commits from worker/cb176-spawn-gate-3d75c8-2 into main 2026-09-03 04:20:23 +02:00
4 changed files with 320 additions and 9 deletions
@@ -3,11 +3,13 @@ package dev.ltms.fleet.member;
import dev.ltms.fleet.config.FleetConfig;
import dev.ltms.fleet.herdr.Agent;
import dev.ltms.fleet.herdr.AgentControl;
import dev.ltms.fleet.herdr.AgentStatus;
import dev.ltms.fleet.herdr.HerdrClient;
import dev.ltms.fleet.herdr.HerdrException;
import dev.ltms.fleet.herdr.Tab;
import dev.ltms.fleet.herdr.Workspace;
import dev.ltms.fleet.herdr.WorkspaceControl;
import dev.ltms.fleet.inject.StatusRefiner;
import dev.ltms.fleet.peer.Capability;
import dev.ltms.fleet.peer.CharterReceipt;
import dev.ltms.fleet.peer.MemberRole;
@@ -151,6 +153,14 @@ public abstract class HerdrPeerLauncher implements PeerLauncher {
private final LongSupplier nowMillis; // monotonic clock (injectable for tests)
private final Runnable sleeper; // sleep/wait hook (injectable for tests; never real-sleep in unit tests)
/**
* fleetd #176 fix 2: the same UNKNOWN-refinement {@code dev.ltms.fleet.inject.StatusPoller}
* uses, reused here for the spawn-readiness gate. Constructed once from {@link #agents} — see
* {@link #refinedInjectable(String, Agent)} for the corroboration that keeps it from firing on
* a dead pane's bare shell prompt.
*/
private final StatusRefiner statusRefiner;
// Per-process token mixed into each peer name so a fresh process (nameSeq back at 0) cannot
// collide with same-profile peers that outlived a restart. See startUniquelyNamed.
private final String nameNonce = String.format("%06x", new SecureRandom().nextInt(1 << 24));
@@ -272,6 +282,7 @@ public abstract class HerdrPeerLauncher implements PeerLauncher {
this.memberCredentials = memberCredentials;
this.hostEnvNames = hostEnvNames != null ? hostEnvNames : () -> System.getenv().keySet();
this.config = config;
this.statusRefiner = new StatusRefiner(agents);
}
// --- adapter seams -------------------------------------------------------------------------
@@ -909,16 +920,35 @@ public abstract class HerdrPeerLauncher implements PeerLauncher {
// --- spawn-readiness gate (CB-306) ---------------------------------------------------------
/**
* Poll {@link AgentControl#status} until the pane reports an injectable state or the configured
* Poll {@link AgentControl#get} until the pane reports an injectable state or the configured
* timeout elapses. On timeout, close the pane (self-reap) and throw.
*
* <p>fleetd #176 fix 1: {@code agents.get} was previously unguarded here, so a herdr
* {@code *_not_found} answer — which is what happens when the backend process EXITED rather
* than being slow — propagated as a raw {@link HerdrException} instead of the
* {@link PeerUnreachableException} every other failure path of this gate produces, and skipped
* teardown ({@link #stop}) entirely, leaking the pane/tab. {@link #failFastOnGoneBackend} closes
* that gap: it stops waiting immediately (never burns the rest of the timeout), runs the same
* teardown the timeout path below runs, and throws with a message that says the backend exited
* rather than that the pane was slow. Any other {@link HerdrException} still propagates
* unchanged — this gate does not know how to recover from it.
*/
private void waitUntilInjectableOrThrow(String paneId) {
long deadline = nowMillis.getAsLong() + spawnReadyTimeoutMs;
Object lastStatus = null;
long start = nowMillis.getAsLong();
long deadline = start + spawnReadyTimeoutMs;
AgentStatus lastStatus = null;
while (nowMillis.getAsLong() < deadline) {
var status = agents.status(paneId);
lastStatus = status;
if (status.injectable()) {
Agent sample;
try {
sample = agents.get(paneId);
} catch (HerdrException e) {
if (isAlreadyGone(e)) {
failFastOnGoneBackend(paneId, e, nowMillis.getAsLong() - start);
}
throw e; // any other herdr failure is not ours to interpret — let it propagate
}
lastStatus = sample.status();
if (lastStatus.injectable() || refinedInjectable(paneId, sample)) {
log.debug("peer pane={} reached injectable state", paneId);
return;
}
@@ -937,6 +967,66 @@ public abstract class HerdrPeerLauncher implements PeerLauncher {
+ spawnReadyTimeoutMs + "ms");
}
/**
* fleetd #176 fix 1: the backend process exited while the gate was still waiting — herdr
* answered {@code *_not_found} instead of ever reporting an injectable status. Fails
* immediately (never burns the rest of {@link #spawnReadyTimeoutMs}), runs the exact same
* teardown {@link #waitUntilInjectableOrThrow}'s timeout path runs, and throws a
* {@link PeerUnreachableException} whose message says the process exited rather than that the
* pane was slow.
*
* @throws PeerUnreachableException always — this method never returns normally
*/
private void failFastOnGoneBackend(String paneId, HerdrException cause, long elapsedMs) {
String tail = readPaneQuietly(paneId); // read before stop() closes the pane
log.warn("peer pane={} backend process exited after {}ms while waiting for injectable "
+ "state (herdr: {}) — closing. Pane tail:\n{}",
paneId, elapsedMs, cause.getMessage(), tail);
stop(paneId);
throw new PeerUnreachableException(
"worker pane " + paneId + " backend process exited after " + elapsedMs
+ "ms while waiting to become injectable (herdr reported: " + cause.getMessage()
+ "). Pane tail:\n" + tail);
}
/**
* fleetd #176 fix 2: resolve a raw {@link AgentStatus#UNKNOWN} sample into a trustworthy
* injectable state via pane content, the same refinement {@code StatusPoller} applies during a
* peer's working life — but corroborated, because the trap this gate is exposed to that the
* poller is not: a pane whose backend has already exited settles at a plain shell prompt, and
* that prompt commonly contains the same {@code ❯} glyph {@link StatusRefiner#classify} treats
* as "idle at the Claude Code TUI prompt". Naively wiring the refiner in would turn "the backend
* died" into "ready to inject" — strictly worse than today's timeout.
*
* <p>Two guards, both required:
* <ul>
* <li>{@link StatusRefiner#classify} is written for the Claude Code TUI only (its own javadoc
* says so), so refinement only ever runs for the {@code claude} adapter — never for
* {@code opencode} or any future non-Claude backend, whatever its pane looks like.</li>
* <li>The refined status is accepted only when the <em>same</em> {@code agents.get} sample
* ({@code sample}, taken once by the caller) still reports a non-null
* {@link Agent#agentType()} — herdr's own "a supported backend is still detected here"
* signal, read from the very sample the raw status came from so the two can never
* disagree. A bare shell prompt left by an exited backend reports no {@code agentType}.</li>
* </ul>
*
* <p>Called only when {@code sample.status() == UNKNOWN}, so a healthy spawn — which never sees
* {@code UNKNOWN} — triggers zero extra herdr calls; only a persistently-{@code unknown} pane
* pays the one extra {@code agent.read} {@link StatusRefiner#refine} performs.
*/
private boolean refinedInjectable(String paneId, Agent sample) {
if (sample.status() != AgentStatus.UNKNOWN) {
return false;
}
if (!"claude".equals(namePrefix)) {
return false; // StatusRefiner.classify reads a Claude Code TUI prompt specifically
}
if (sample.agentType() == null) {
return false; // no corroborating liveness signal — could be a dead pane's bare shell
}
return statusRefiner.refine(paneId, AgentStatus.UNKNOWN, agents).injectable();
}
/**
* fleetd #220: the pane's recent output, clipped, for the readiness-gate timeout log — or a
* short note when it cannot be read. Best-effort by construction: this runs on a path that is
@@ -44,10 +44,13 @@ public final class FakeHerdr implements HerdrClient {
private String agentSendErrorCode = null;
private boolean noPanes = false;
private volatile String agentStatus = "idle"; // steady-state agent.get status
private volatile String agentType = "claude"; // detected agent kind on agent.get; null = undetected
private volatile String readText = "worker transcript tail"; // canned agent.read output
private int pinnedStarts = 0; // how many upcoming agent.start calls report a fixed pane
private String pinnedStartTerminal;
private String pinnedStartPane;
private volatile int agentGetOkCalls = Integer.MAX_VALUE; // how many agent.get calls succeed first
private volatile String agentGetFailCode = null; // error code every agent.get call after that reports
public FakeHerdr healthy(boolean h) {
this.healthy = h;
@@ -103,6 +106,27 @@ public final class FakeHerdr implements HerdrClient {
return this;
}
/**
* Set the detected agent kind ({@code "agent"} field) that {@code agent.get} reports —
* {@code null} models herdr not (or no longer) detecting a supported backend in the pane, e.g.
* a bare shell prompt (fleetd #176 fix 2 corroboration test).
*/
public FakeHerdr agentType(String type) {
this.agentType = type;
return this;
}
/**
* Make {@code agent.get} succeed normally for its first {@code okCalls} invocations, then fail
* every call after that with {@code code} — fleetd #176 fix 1's "backend exited mid-wait"
* fixture. {@code okCalls == 0} fails from the very first call.
*/
public FakeHerdr agentGetFailsWithAfter(int okCalls, String code) {
this.agentGetOkCalls = okCalls;
this.agentGetFailCode = code;
return this;
}
/** The text {@code agent.read} returns (the CB-106 completion scrape). */
public FakeHerdr readText(String text) {
this.readText = text;
@@ -208,10 +232,21 @@ public final class FakeHerdr implements HerdrClient {
}
yield mapper.readTree("{\"type\":\"ok\"}");
}
case "agent.get" -> mapper.readTree(("""
{"type":"agent_info","agent":{"terminal_id":"term_a","agent":"claude",
case "agent.get" -> {
if (agentGetFailCode != null) {
long getCalls = calls.stream().filter(c -> c.method().equals("agent.get")).count();
if (getCalls > agentGetOkCalls) {
throw new HerdrException(
"herdr error [" + agentGetFailCode + "]: agent target not found",
agentGetFailCode, null);
}
}
String agentField = agentType == null ? "null" : "\"" + agentType + "\"";
yield mapper.readTree(("""
{"type":"agent_info","agent":{"terminal_id":"term_a","agent":%s,
"agent_status":"%s","workspace_id":"w2","tab_id":"w2:t7","pane_id":"w2:p7"}}""")
.formatted(agentStatus));
.formatted(agentField, agentStatus));
}
case "agent.read" -> mapper.readTree(mapper.writeValueAsString(
java.util.Map.of("type", "agent_read", "read", java.util.Map.of("text", readText))));
case "agent.start" -> {
@@ -963,6 +963,152 @@ class ClaudeCodeLauncherTest {
assertDoesNotThrow(() -> UUID.fromString(handle.id()));
}
// --- fleetd #176 fix 1: fail fast when the backend process exits mid-wait -------------------
@Test
void spawnFailsFastWhenBackendProcessExitsMidWaitInsteadOfBurningTheTimeout() {
// First agent.get sees UNKNOWN (one normal tick); the second reports the pane gone, exactly
// what herdr answers when the backend process has already exited. The timeout is generous
// (60s) so a test that wrongly falls through to the old unguarded call — and therefore
// waits out the whole window — is unambiguously distinguishable from one that fails fast.
FakeHerdr herdr = new FakeHerdr();
herdr.agentStatus("unknown");
herdr.agentGetFailsWithAfter(1, "pane_not_found");
long[] clock = {0};
ClaudeCodeLauncher svc = new ClaudeCodeLauncher(
new AgentControl(herdr), new WorkspaceControl(herdr),
new SubscriptionGuard(Set.of("gx00.gw")),
workerConfigMap("ltms-local", null), "ltms-local", _ -> null,
60_000, () -> clock[0], () -> clock[0] += 50);
PeerUnreachableException ex = assertThrows(
PeerUnreachableException.class,
() -> svc.spawn(new SpawnRequest(null, null, null)));
assertTrue(ex.getMessage().contains("w9:pRoot_1"),
"exception message references the paneId: " + ex.getMessage());
assertTrue(ex.getMessage().toLowerCase().contains("exited"),
"exception message says the backend exited, not that the pane was slow: "
+ ex.getMessage());
assertTrue(clock[0] < 60_000,
"the gate must not burn the rest of the 60s timeout: clock only reached " + clock[0]);
long getCalls = herdr.calls.stream().filter(c -> c.method().equals("agent.get")).count();
assertEquals(2, getCalls,
"exactly one normal poll then the not_found answer — no further polling after that: "
+ getCalls);
assertEquals(1, paneCloseCount(herdr, "w9:pRoot_1"),
"the pane is torn down (no orphan) even on the fail-fast path");
}
@Test
void spawnLetsAnUnrelatedHerdrErrorPropagateUnchanged() {
// Fix 1 must only special-case a "*_not_found" answer. Any other herdr failure keeps
// propagating as-is — this gate does not know how to recover from it.
FakeHerdr herdr = new FakeHerdr();
herdr.agentStatus("unknown");
herdr.agentGetFailsWithAfter(0, "internal_error");
long[] clock = {0};
ClaudeCodeLauncher svc = new ClaudeCodeLauncher(
new AgentControl(herdr), new WorkspaceControl(herdr),
new SubscriptionGuard(Set.of("gx00.gw")),
workerConfigMap("ltms-local", null), "ltms-local", _ -> null,
60_000, () -> clock[0], () -> clock[0] += 50);
dev.ltms.fleet.herdr.HerdrException ex = assertThrows(
dev.ltms.fleet.herdr.HerdrException.class,
() -> svc.spawn(new SpawnRequest(null, null, null)));
assertEquals("internal_error", ex.code());
assertEquals(0, paneCloseCount(herdr, "w9:pRoot_1"),
"an error this gate does not recognize is not this gate's teardown to run");
}
// --- fleetd #176 fix 2: corroborated UNKNOWN refinement --------------------------------------
@Test
void refinedIdleIsNotAcceptedWhenAgentTypeIsNull() {
// The trap fix 2 must close: a pane sitting at a bare shell prompt after its backend exited
// still contains the same "❯" glyph StatusRefiner.classify treats as "idle at the Claude
// Code TUI prompt". Without the agentType corroboration this would be misread as injectable
// and the gate would hand back a peer that never started. herdr reports no agentType for
// that bare shell.
FakeHerdr herdr = new FakeHerdr();
herdr.agentStatus("unknown"); // always UNKNOWN
herdr.agentType(null); // no supported backend detected — could be a bare shell
herdr.readText("some-host:~ user$ ❯ "); // looks exactly like an idle Claude Code prompt
long[] clock = {0};
ClaudeCodeLauncher svc = new ClaudeCodeLauncher(
new AgentControl(herdr), new WorkspaceControl(herdr),
new SubscriptionGuard(Set.of("gx00.gw")),
workerConfigMap("ltms-local", null), "ltms-local", _ -> null,
500, () -> clock[0], () -> clock[0] += 50);
PeerUnreachableException ex = assertThrows(
PeerUnreachableException.class,
() -> svc.spawn(new SpawnRequest(null, null, null)));
assertTrue(clock[0] >= 500,
"a null agentType must not let the '❯' prompt refine to injectable — the gate has "
+ "to wait out the full timeout: clock only reached " + clock[0]);
assertEquals(1, paneCloseCount(herdr, "w9:pRoot_1"),
"the pane is torn down on timeout, same as any other never-injectable spawn");
}
@Test
void refinedIdleIsAcceptedWhenAgentTypeCorroboratesLiveness() {
// The positive case: a genuinely live claude pane that herdr misreports as UNKNOWN (CB-115)
// still resolves to injectable once agentType corroborates that a supported backend is
// detected in the same sample.
FakeHerdr herdr = new FakeHerdr();
herdr.agentStatus("unknown"); // always UNKNOWN at the raw level
herdr.agentType("claude"); // herdr still detects a live claude backend
herdr.readText("? for shortcuts"); // StatusRefiner.classify's idle footer marker
long[] clock = {0};
ClaudeCodeLauncher svc = new ClaudeCodeLauncher(
new AgentControl(herdr), new WorkspaceControl(herdr),
new SubscriptionGuard(Set.of("gx00.gw")),
workerConfigMap("ltms-local", null), "ltms-local", _ -> null,
60_000, () -> clock[0], () -> clock[0] += 50);
PeerHandle handle = svc.spawn(new SpawnRequest(null, null, null));
assertNotNull(handle, "a corroborated refined-IDLE sample lets the spawn succeed");
assertTrue(clock[0] < 60_000,
"refinement must resolve well before the timeout: clock reached " + clock[0]);
assertEquals(0, paneCloseCount(herdr, "w9:pRoot_1"),
"no pane close — the peer is genuinely injectable");
}
@Test
void refinementNeverFiresWhenRawStatusIsAlreadyInjectable() {
// Acceptance criterion 4: refinement must trigger only on a raw UNKNOWN sample. Seed the
// pane content with an active-generation marker that StatusRefiner.classify would read as
// WORKING (never injectable) if refine() were wrongly invoked here — proving that a raw
// IDLE status short-circuits before refine() (and its extra agent.read call) ever runs.
FakeHerdr herdr = new FakeHerdr();
herdr.agentStatus("idle"); // already injectable at the raw level
herdr.agentType("claude");
herdr.readText("esc to interrupt"); // would classify as WORKING if refine() ran anyway
long[] clock = {0};
ClaudeCodeLauncher gated = new ClaudeCodeLauncher(
new AgentControl(herdr), new WorkspaceControl(herdr),
new SubscriptionGuard(Set.of("gx00.gw")),
workerConfigMap("ltms-local", null), "ltms-local", _ -> null,
5000, () -> clock[0], () -> clock[0] += 300);
PeerHandle handle = gated.spawn(new SpawnRequest(null, null, null));
assertNotNull(handle, "an already-injectable raw status succeeds without ever refining");
assertFalse(herdr.called("agent.read"),
"refine() must never run (and so never call agent.read) when the raw status is "
+ "already injectable");
}
// --- CB-511: worker environment seeding -----------------------------------------------------
@Test
@@ -396,6 +396,46 @@ class OpenCodeLauncherTest {
assertNotNull(ex.getMessage());
}
/**
* fleetd #176 fix 2's per-adapter guard: {@code StatusRefiner.classify} is written for the
* Claude Code TUI only, and the spawn-readiness gate must never run it against an opencode
* pane. {@code agentType("opencode")} deliberately satisfies the OTHER guard (the corroborating
* liveness check) so it cannot be what makes this test pass — only the {@code namePrefix}
* check can be. If that check were ever removed, this pane's {@code ❯} content would refine
* straight to IDLE and the gate would report ready before the backend actually was.
*/
@Test
void opencodePaneIsNeverRefinedEvenWhenItsContentLooksLikeAnIdleClaudePrompt(@TempDir Path root) {
FakeHerdr herdr = new FakeHerdr();
herdr.agentStatus("unknown"); // always UNKNOWN
herdr.agentType("opencode"); // non-null — satisfies the liveness guard on its own
herdr.readText("some-host:~ user$ ❯ "); // content StatusRefiner.classify reads as IDLE
long[] clock = {0};
OpenCodeLauncher svc = new OpenCodeLauncher(new AgentControl(herdr), new WorkspaceControl(herdr),
Map.of("gemini", opencodeCfg(null, null, null)), "gemini", _ -> null,
1000, () -> clock[0], () -> clock[0] += 50, root, root);
assertThrows(PeerUnreachableException.class,
() -> svc.spawn(new SpawnRequest(null, null, null)));
assertTrue(clock[0] >= 1000,
"an opencode pane must never refine to injectable, however its content reads — "
+ "the gate has to wait out the full timeout: clock only reached " + clock[0]);
// A blanket "agent.read is never called" does not hold here: the timeout path itself reads
// the pane tail (source=recent) for its own log message, on every timeout, regardless of
// adapter — see HerdrPeerLauncher.readPaneQuietly. So assert on the refiner's OWN probe
// source (StatusRefiner.PROBE_SOURCE = "detection") instead — that call happens only inside
// StatusRefiner.refine, so its absence proves the refiner itself was never reached for this
// opencode pane, not merely that its answer was discarded.
long detectionReads = herdr.calls.stream()
.filter(c -> c.method().equals("agent.read"))
.filter(c -> "detection".equals(((Map<?, ?>) c.params()).get("source")))
.count();
assertEquals(0, detectionReads,
"the refiner's own pane probe (source=detection) must never run against an "
+ "opencode pane — the namePrefix guard has to stop it before that call");
}
@Test
void spawnReturnsHandleWhenGateDisabled(@TempDir Path root) {
FakeHerdr herdr = new FakeHerdr();