alice.pds.demo.boltless.dev
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1package microvm
2
3import (
4 "context"
5 "encoding/json"
6 "errors"
7 "fmt"
8 "io"
9 "log/slog"
10 "net/http"
11 "os"
12 "path/filepath"
13 "slices"
14 "strings"
15 "sync"
16 "sync/atomic"
17 "time"
18
19 "gopkg.in/yaml.v3"
20
21 "tangled.org/core/api/tangled"
22 "tangled.org/core/log"
23 "tangled.org/core/spindle/agentproto"
24 agentv1 "tangled.org/core/spindle/agentproto/gen"
25 "tangled.org/core/spindle/config"
26 "tangled.org/core/spindle/db"
27 "tangled.org/core/spindle/engine"
28 "tangled.org/core/spindle/models"
29 "tangled.org/core/spindle/secrets"
30)
31
32const (
33 guestWorkDir = "/workspace/repo"
34 guestBasePATH = "/run/current-system/sw/bin:/nix/var/nix/profiles/default/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin"
35 guestDevShellEnvPath = "/run/spindle/devshell-env.sh"
36 activationStepAction = "activate-config"
37 agentAcceptTimeout = 2 * time.Minute
38 agentHandshakeTimeout = 30 * time.Second
39 cacheDrainTimeout = 5 * time.Minute
40 vmShutdownTimeout = 10 * time.Second
41 guestTimeoutGrace = 5 * time.Second
42)
43
44type cleanupFunc func(context.Context) error
45
46type Engine struct {
47 l *slog.Logger
48 cfg *config.Config
49 db *db.DB
50 agentMu sync.Mutex
51 agent *agentHub
52 scheduler *engine.ResourceScheduler[Resources]
53 cgroupParent *CgroupParent
54
55 cleanupMu sync.Mutex
56 cleanup map[string][]cleanupFunc
57}
58
59type Step struct {
60 name string
61 kind models.StepKind
62 command string
63 environment map[string]string
64 action string
65 config manifestConfig
66 configKey string
67}
68
69func (s Step) Name() string { return s.name }
70func (s Step) Command() string { return s.command }
71func (s Step) Kind() models.StepKind { return s.kind }
72
73func New(ctx context.Context, cfg *config.Config, d *db.DB) (*Engine, error) {
74 l := log.FromContext(ctx).With("component", "engine.microvm")
75 budget, max, agingThreshold := newVMBudgetConfig(cfg.MicroVMPipelines)
76 l.Info("initialized microVM workflow budget", "budget", budget.String(), "maxWorkflow", max.String(), "agingThreshold", agingThreshold)
77
78 var cgroupParent *CgroupParent
79 var err error
80 if cfg.MicroVMPipelines.EnableCgroups {
81 cgroupParent, err = initCgroupParent(cfg.MicroVMPipelines.CgroupParent, cfg.MicroVMPipelines.CgroupSupervisorMemoryMinMiB, l)
82 if err != nil {
83 return nil, err
84 }
85 }
86
87 return &Engine{
88 l: l,
89 cfg: cfg,
90 db: d,
91 scheduler: engine.NewResourceScheduler(budget, max, agingThreshold),
92 cgroupParent: cgroupParent,
93 cleanup: make(map[string][]cleanupFunc),
94 }, nil
95}
96
97func (e *Engine) ensureAgentHub() (*agentHub, error) {
98 e.agentMu.Lock()
99 defer e.agentMu.Unlock()
100
101 if e.agent != nil {
102 return e.agent, nil
103 }
104
105 port := e.cfg.MicroVMPipelines.AgentPort
106 if port == 0 {
107 port = agentproto.DefaultPort
108 }
109 agent, err := newAgentHub(port, e.l)
110 if err != nil {
111 return nil, err
112 }
113 e.agent = agent
114 return agent, nil
115}
116
117func (e *Engine) InitWorkflow(twf tangled.Pipeline_Workflow, tpl tangled.Pipeline) (*models.Workflow, error) {
118 swf := &models.Workflow{}
119 var dwf manifestWorkflow
120
121 if err := engine.DescribeManifestError(twf.Raw, manifestWorkflow{}); err != nil {
122 return nil, err
123 }
124 if err := yaml.Unmarshal([]byte(twf.Raw), &dwf); err != nil {
125 return nil, err
126 }
127
128 for _, dstep := range dwf.Steps {
129 swf.Steps = append(swf.Steps, Step{
130 name: dstep.Name,
131 kind: models.StepKindUser,
132 command: dstep.Command,
133 environment: dstep.Environment,
134 })
135 }
136 swf.Name = twf.Name
137 swf.Environment = dwf.Environment
138
139 if tpl.TriggerMetadata != nil {
140 if clone := models.BuildCloneStep(twf, *tpl.TriggerMetadata, e.cfg.Server.Dev); clone.Command() != "" {
141 swf.Steps = append([]models.Step{clone}, swf.Steps...)
142 }
143 }
144
145 imageSpec, imageSpecPath, imageName, err := e.resolveImage(dwf.Image)
146 if err != nil {
147 return nil, err
148 }
149 configKey := ""
150 config := manifestConfig{
151 Services: dwf.Services,
152 Virtualisation: dwf.Virtualisation,
153 Dependencies: dwf.Dependencies,
154 Registry: dwf.Registry,
155 }
156 if config.Enabled() {
157 if !imageSpec.SupportsConfigActivation() {
158 return nil, fmt.Errorf(
159 "microVM image %q is not a NixOS image: services, virtualisation, dependencies and registry workflow options require a NixOS image",
160 imageName,
161 )
162 }
163 var err error
164 configKey, err = buildConfigKey(imageSpec, config)
165 if err != nil {
166 return nil, fmt.Errorf("build config key: %w", err)
167 }
168 activationStep := Step{
169 name: "NixOS config activation",
170 kind: models.StepKindSystem,
171 command: "activate nixos config",
172 action: activationStepAction,
173 config: config,
174 configKey: configKey,
175 }
176
177 insertAt := 0
178 if len(swf.Steps) > 0 && swf.Steps[0].Kind() == models.StepKindSystem {
179 insertAt = 1
180 }
181 swf.Steps = append(swf.Steps, nil)
182 copy(swf.Steps[insertAt+1:], swf.Steps[insertAt:])
183 swf.Steps[insertAt] = activationStep
184 }
185
186 cacheURLs, cacheKeys, err := workflowCaches(dwf.Caches)
187 if err != nil {
188 return nil, err
189 }
190
191 swf.Data = &workflowState{
192 ImageSpec: imageSpec,
193 ImageSpecPath: imageSpecPath,
194 Config: config,
195 ConfigKey: configKey,
196 Image: imageName,
197 CacheReadURLs: cacheURLs,
198 CacheTrustedPublicKeys: cacheKeys,
199 NixOSToplevelCache: newNixOSToplevelCacheStore(e.db),
200 }
201 return swf, nil
202}
203
204func (e *Engine) SetupWorkflow(ctx context.Context, wid models.WorkflowId, wf *models.Workflow, wfLogger models.WorkflowLogger) (err error) {
205 l := e.l.With("workflow", wid)
206 setupStep := Step{name: "microVM setup", kind: models.StepKindSystem}
207
208 wfLogger.ControlWriter(-1, setupStep, models.StepStatusStart).Write([]byte{0})
209 defer wfLogger.ControlWriter(-1, setupStep, models.StepStatusEnd).Write([]byte{0})
210
211 category := "Failed to setup VM"
212 defer func() {
213 if err != nil {
214 err = fmt.Errorf("%s:\n%w", category, err)
215 }
216 }()
217
218 state, ok := wf.Data.(*workflowState)
219 if !ok || state == nil {
220 return fmt.Errorf("workflow state is not initialized")
221 }
222
223 cid, err := AllocateCID()
224 if err != nil {
225 return err
226 }
227 agent, err := e.ensureAgentHub()
228 if err != nil {
229 return err
230 }
231 connCh, unregister, err := agent.expect(cid)
232 if err != nil {
233 return err
234 }
235 defer unregister()
236
237 workDirBase := e.cfg.MicroVMPipelines.OverlayDir
238 if workDirBase == "" {
239 workDirBase = os.TempDir()
240 }
241 workDir, err := os.MkdirTemp(workDirBase, "spindle-microvm-"+wid.String()+"-*")
242 if err != nil {
243 return fmt.Errorf("create workflow microVM directory: %w", err)
244 }
245 state.WorkDir = workDir
246
247 setupDone := false
248 defer func() {
249 if setupDone {
250 return
251 }
252 if detail := VMCrashLog(state.VM); detail != "" {
253 l.Error("microVM setup failed", "detail", detail)
254 }
255 if err := e.cleanupState(context.Background(), wid, state); err != nil {
256 l.Error("failed to cleanup failed setup", "error", err)
257 }
258 }()
259
260 upstreams, err := BuildCacheUpstreams(e.cfg.NixCache.ReadURLs, state.CacheReadURLs)
261 if err != nil {
262 return err
263 }
264 readCache, err := StartReadCacheProxy(ctx, cid, upstreams, l)
265 if err != nil {
266 return err
267 }
268 state.ReadCache = readCache
269 stagingDir := filepath.Join(workDir, "upload-cache")
270 uploadCache, err := StartUploadCacheProxy(ctx, cid, e.cfg.NixCache.UploadURL, upstreams, stagingDir, l)
271 if err != nil {
272 return err
273 }
274 state.UploadCache = uploadCache
275 dnsProxy, err := StartDNSProxy(ctx, cid, l)
276 if err != nil {
277 return err
278 }
279 state.DNSProxy = dnsProxy
280
281 port := e.cfg.MicroVMPipelines.AgentPort
282 if port == 0 {
283 port = agentproto.DefaultPort
284 }
285 state.ImageSpec.BootArgs = fmt.Sprintf("%s shuttle.vsock_port=%d", state.ImageSpec.BootArgs, port)
286
287 fmt.Fprintf(wfLogger.DataWriter(-1, "stdout"), "starting microVM image %s\n", state.Image)
288 l.Info("starting microVM workflow", "image", state.Image, "imageSpec", state.ImageSpecPath, "cid", cid, "workDir", workDir)
289
290 var vm VMHandle
291 vm, err = StartVM(ctx, VMConfig{
292 Image: state.ImageSpec,
293 CID: cid,
294 EnableKVM: e.cfg.MicroVMPipelines.EnableKVM,
295 WorkDir: workDir,
296 Cgroup: e.cgroupLimits(wid, state.ImageSpec),
297 Dev: e.cfg.Server.Dev,
298 }, l)
299 if err != nil {
300 return err
301 }
302 state.VM = vm
303
304 category = "Failed to connect to agent"
305
306 acceptCtx, cancelAccept := context.WithTimeout(ctx, agentAcceptTimeout)
307 defer cancelAccept()
308 conn, err := waitAgentConn(acceptCtx, connCh)
309 if err != nil {
310 return err
311 }
312
313 agentSession := NewAgentSession(conn, l)
314 initCtx, cancelInit := context.WithTimeout(ctx, agentHandshakeTimeout)
315 defer cancelInit()
316 if err := agentSession.Init(initCtx, &agentv1.Init{
317 JobId: wid.String(),
318 CacheTrustedPublicKeys: append(slices.Clone(e.cfg.NixCache.TrustedPublicKeys), state.CacheTrustedPublicKeys...),
319 CacheReadProxyPort: readCache.Port(),
320 CacheUploadProxyPort: uploadCache.Port(),
321 DnsProxyPort: dnsProxy.Port(),
322 }); err != nil {
323 _ = agentSession.Close()
324 return err
325 }
326 state.Agent = agentSession
327 wf.Data = state
328
329 e.registerCleanup(wid, func(ctx context.Context) error {
330 return e.cleanupState(ctx, wid, state)
331 })
332 setupDone = true
333
334 fmt.Fprintf(wfLogger.DataWriter(-1, "stdout"),
335 "agent connected; serial log: %s\n", vm.Logs().Serial,
336 )
337 return nil
338}
339
340func applyDepsSource(command string) string {
341 return fmt.Sprintf(
342 // check if it exists because not all images have this
343 `if [ -f %s ]; then . %s; export PATH="$PATH:%s"; fi; %s`,
344 guestDevShellEnvPath, guestDevShellEnvPath, guestBasePATH, command,
345 )
346}
347
348func (e *Engine) RunStep(ctx context.Context, wid models.WorkflowId, w *models.Workflow, idx int, secrets []secrets.UnlockedSecret, wfLogger models.WorkflowLogger) error {
349 state, ok := w.Data.(*workflowState)
350 if !ok || state == nil || state.Agent == nil {
351 return fmt.Errorf("microVM workflow is not connected to agent")
352 }
353
354 stderr := wfLogger.DataWriter(idx, "stderr")
355
356 execCtx, vmExited, cancelWatch := watchVMExit(ctx, state.VM)
357 defer cancelWatch()
358
359 step := w.Steps[idx]
360 if s, ok := step.(Step); ok && s.action == activationStepAction {
361 err := e.activateConfig(execCtx, wid, state, s, wfLogger.DataWriter(idx, "stdout"))
362 return e.classifyStepError(ctx, wid, step, state, stderr, vmExited, "Failed to activate config", err)
363 }
364 env := []string{
365 "HOME=/workspace",
366 "LOGNAME=" + guestWorkflowUser,
367 "PATH=" + guestBasePATH,
368 "USER=" + guestWorkflowUser,
369 }
370 for k, v := range w.Environment {
371 env = append(env, k+"="+v)
372 }
373 for _, s := range secrets {
374 env = append(env, s.Key+"="+s.Value)
375 }
376 if s, ok := step.(Step); ok {
377 for k, v := range s.environment {
378 env = append(env, k+"="+v)
379 }
380 }
381
382 stdout := wfLogger.DataWriter(idx, "stdout")
383 exitCode, err := state.Agent.Exec(execCtx, AgentExec{
384 ID: fmt.Sprintf("%s-%d", wid.String(), idx),
385 ExecStart: &agentv1.ExecStart{
386 Argv: []string{state.ImageSpec.Shell, "-lc", applyDepsSource(step.Command())},
387 Env: env,
388 Cwd: guestWorkDir,
389 User: guestWorkflowUser,
390 // timeout not set here, Exec will fill it
391 },
392 Stdout: stdout,
393 Stderr: stderr,
394 })
395 if err != nil {
396 return e.classifyStepError(ctx, wid, step, state, stderr, vmExited, "User step error", err)
397 }
398
399 if exitCode != 0 {
400 e.l.Debug("step exited non-zero", "workflow", wid, "step", step.Name(), "exitCode", exitCode)
401 return fmt.Errorf("User step error: exited with code %d", exitCode)
402 }
403 return nil
404}
405
406// reads the vm serial logs so we report the tail of that as an error instead of
407// just "guest agent connection lost: EOF"
408func (e *Engine) classifyStepError(ctx context.Context, wid models.WorkflowId, step models.Step, state *workflowState, stderr io.Writer, vmExited *atomic.Bool, category string, err error) error {
409 if err == nil {
410 return nil
411 }
412 l := e.l.With("workflow", wid, "step", step.Name())
413
414 if vmExited != nil && vmExited.Load() {
415 reason := "microVM exited unexpectedly"
416 oom := state.VM != nil && state.VM.OOMKilled()
417 if oom {
418 reason = "microVM killed by OOM (cgroup memory limit exceeded)"
419 }
420 if detail := VMCrashLog(state.VM); detail != "" {
421 fmt.Fprintf(stderr, "%s:\n%s\n", reason, detail)
422 l.Error(reason, "oom", oom, "detail", detail)
423 } else {
424 fmt.Fprintln(stderr, reason)
425 l.Error(reason, "oom", oom)
426 }
427 return fmt.Errorf("%s:\n%w", category, errors.New(reason+"; see workflow logs for serial output"))
428 }
429
430 if errors.Is(err, errGuestTimedOut) || ctx.Err() != nil {
431 l.Debug("step timed out", "guestReported", errors.Is(err, errGuestTimedOut))
432 return engine.ErrTimedOut
433 }
434
435 // the agent connection dropped while qemu stayed up (eg. the guest kernel
436 // OOM-killed the agent or a guest panic), so surface serial logs, those
437 // will be more helpful.
438 var crashErr error
439 if detail := VMCrashLog(state.VM); detail != "" {
440 fmt.Fprintf(stderr, "step failed (%v):\n%s\n", err, detail)
441 l.Error("step failed", "error", err, "detail", detail)
442 if parsedErr, ok := ParseCrashLog(detail); ok {
443 crashErr = parsedErr
444 } else {
445 if strings.Contains(err.Error(), "guest exec error:") {
446 crashErr = err
447 } else {
448 crashErr = fmt.Errorf("guest agent connection lost: %w", err)
449 }
450 }
451 } else {
452 l.Error("step failed", "error", err)
453 crashErr = err
454 }
455 return fmt.Errorf("%s:\n%w", category, crashErr)
456}
457
458func (e *Engine) activateConfig(ctx context.Context, wid models.WorkflowId, state *workflowState, step Step, out io.Writer) error {
459 cfg := step.config
460 if !cfg.Enabled() {
461 return nil
462 }
463
464 configKey := step.configKey
465 if configKey == "" {
466 configKey = state.ConfigKey
467 }
468
469 userConfigJSON, err := json.Marshal(cfg)
470 if err != nil {
471 return fmt.Errorf("encode user config: %w", err)
472 }
473
474 var cachedToplevel string
475 if configKey != "" {
476 if record, ok, err := state.NixOSToplevelCache.Lookup(configKey); err != nil {
477 return err
478 } else if ok {
479 // todo(dawn): we should probably use gc roots to eliminate TOCTOU
480 // the spindle will have to manage the gc roots, and for remote we have to
481 // ssh in to the host and add / remove gc root.
482 // we need to have this check anyway since the only check http caches can
483 // use is this one, since we cant manage gc roots there...
484 if e.anyCacheHasPath(ctx, state, record.Toplevel) {
485 cachedToplevel = record.Toplevel
486 fmt.Fprintf(out, "realizing cached NixOS config %s\n", cachedToplevel)
487 }
488 }
489 }
490 if cachedToplevel == "" {
491 fmt.Fprintf(out, "building NixOS config from user config\n")
492 }
493
494 baseHash, err := BaseConfigHash(state.ImageSpec)
495 if err != nil {
496 return fmt.Errorf("calculate base config hash: %w", err)
497 }
498
499 result, err := state.Agent.ActivateConfig(ctx, fmt.Sprintf("%s-config", wid.String()), &agentv1.ActivateConfig{
500 ConfigKey: configKey,
501 BaseConfigHash: baseHash,
502 UserConfig: string(userConfigJSON),
503 Toplevel: cachedToplevel,
504 }, out)
505 if err != nil {
506 return err
507 }
508 fmt.Fprintf(out, "activated NixOS config toplevel %s\n", result.Toplevel)
509
510 if cachedToplevel != "" || configKey == "" {
511 return nil
512 }
513 if e.cfg.NixCache.UploadURL == "" {
514 e.l.Warn("not committing config cache metadata: no upload URL configured", "workflow", wid, "configKey", configKey, "toplevel", result.Toplevel)
515 return nil
516 }
517
518 if err := e.drainNixCache(ctx, state); err != nil {
519 // a partial upload would leave the cache unable to realize this toplevel,
520 // so skip the metadata commit rather than poison it with an un-realizable
521 // key. the config still activated fine, so don't fail the workflow.
522 e.l.Warn("cache drain failed; skipping config cache metadata commit", "workflow", wid, "configKey", configKey, "toplevel", result.Toplevel, "error", err)
523 return nil
524 }
525 if err := state.NixOSToplevelCache.Commit(configKey, result.Toplevel); err != nil {
526 return err
527 }
528 fmt.Fprintf(out, "committed config cache metadata %s -> %s\n", configKey, result.Toplevel)
529 return nil
530}
531
532func (e *Engine) anyCacheHasPath(ctx context.Context, state *workflowState, storePath string) bool {
533 upstreams, err := BuildCacheUpstreams(e.cfg.NixCache.ReadURLs, state.CacheReadURLs)
534 if err != nil {
535 e.l.Warn("config cache check: build upstreams failed; treating as absent", "path", storePath, "error", err)
536 return false
537 }
538 if len(upstreams) == 0 {
539 return false
540 }
541 hash, _, err := parseStorePath(storePath)
542 if err != nil {
543 e.l.Warn("config cache check: invalid toplevel path; treating as absent", "path", storePath, "error", err)
544 return false
545 }
546 req, err := http.NewRequestWithContext(ctx, http.MethodHead, "http://upstream/"+hash+".narinfo", nil)
547 if err != nil {
548 e.l.Warn("config cache check: build request failed; treating as absent", "path", storePath, "error", err)
549 return false
550 }
551 resp, err := newNarinfoExistenceTransport(upstreams, e.l).RoundTrip(req)
552 if err != nil {
553 e.l.Warn("config cache check: narinfo probe failed; treating as absent", "path", storePath, "error", err)
554 return false
555 }
556 defer resp.Body.Close()
557 _, _ = io.Copy(io.Discard, resp.Body)
558 return resp.StatusCode == http.StatusOK
559}
560
561func (e *Engine) DestroyWorkflow(ctx context.Context, wid models.WorkflowId) error {
562 fns := e.drainCleanups(wid)
563
564 var cleanupErr error
565 for i := len(fns) - 1; i >= 0; i-- {
566 if err := fns[i](ctx); err != nil {
567 e.l.Error("failed to cleanup workflow resource", "workflowId", wid, "error", err)
568 cleanupErr = errors.Join(cleanupErr, err)
569 }
570 }
571 return cleanupErr
572}
573
574func (e *Engine) FinalizeWorkflow(ctx context.Context, wid models.WorkflowId, w *models.Workflow, wfLogger models.WorkflowLogger) error {
575 return nil
576}
577
578func (e *Engine) WorkflowTimeout() time.Duration {
579 d, err := time.ParseDuration(e.cfg.MicroVMPipelines.WorkflowTimeout)
580 if err != nil {
581 d = 5 * time.Minute
582 }
583 return d + guestTimeoutGrace
584}
585
586func (e *Engine) registerCleanup(wid models.WorkflowId, fn cleanupFunc) {
587 e.cleanupMu.Lock()
588 defer e.cleanupMu.Unlock()
589 key := wid.String()
590 e.cleanup[key] = append(e.cleanup[key], fn)
591}
592
593func (e *Engine) drainCleanups(wid models.WorkflowId) []cleanupFunc {
594 e.cleanupMu.Lock()
595 defer e.cleanupMu.Unlock()
596 key := wid.String()
597 fns := e.cleanup[key]
598 delete(e.cleanup, key)
599 return fns
600}
601
602func (e *Engine) cgroupLimits(wid models.WorkflowId, spec ImageSpec) CgroupLimits {
603 cfg := e.cfg.MicroVMPipelines
604 return CgroupLimits{
605 Enabled: cfg.EnableCgroups,
606 Parent: e.cgroupParent,
607 Name: "workflow-" + wid.String(),
608 MemoryMaxMiB: resourcesForImage(spec).MemoryMiB,
609 SwapMaxMiB: cfg.CgroupSwapMaxMiB,
610 PidsMax: cfg.CgroupPidsMax,
611 }
612}