Monorepo for Tangled
spindle/engines: add dummy engine that logs to stdout
Useful during local testing.
Signed-off-by: Anirudh Oppiliappan <anirudh@tangled.org>
Anirudh Oppiliappan
(May 4, 2026, 11:33 PM +0300)
032aa7e0
260ce507
+95
+92
spindle/engines/dummy/engine.go
+92
spindle/engines/dummy/engine.go
···
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package dummy
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import (
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"context"
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"fmt"
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"log/slog"
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"time"
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"gopkg.in/yaml.v3"
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"tangled.org/core/api/tangled"
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"tangled.org/core/spindle/models"
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"tangled.org/core/spindle/secrets"
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)
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// DummyEngine is a no-op engine that logs all lifecycle events via slog and writes
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// step output to the workflow logger. Useful for testing pipeline plumbing
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// without a real execution backend.
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type DummyEngine struct {
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l *slog.Logger
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}
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func New(l *slog.Logger) *DummyEngine {
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return &DummyEngine{l: l.With("engine", "dummy")}
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}
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type Step struct {
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name string
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kind models.StepKind
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command string
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}
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func (s Step) Name() string { return s.name }
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func (s Step) Command() string { return s.command }
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func (s Step) Kind() models.StepKind { return s.kind }
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func (e *DummyEngine) InitWorkflow(twf tangled.Pipeline_Workflow, _ tangled.Pipeline) (*models.Workflow, error) {
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dwf := &struct {
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Steps []struct {
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Name string `yaml:"name"`
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Command string `yaml:"command"`
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} `yaml:"steps"`
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Environment map[string]string `yaml:"environment"`
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}{}
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if err := yaml.Unmarshal([]byte(twf.Raw), dwf); err != nil {
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return nil, err
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}
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wf := &models.Workflow{
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Name: twf.Name,
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Environment: dwf.Environment,
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}
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for _, ds := range dwf.Steps {
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wf.Steps = append(wf.Steps, Step{
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name: ds.Name,
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kind: models.StepKindUser,
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command: ds.Command,
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})
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}
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e.l.Info("workflow initialised", "name", twf.Name, "steps", len(wf.Steps))
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return wf, nil
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}
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func (e *DummyEngine) SetupWorkflow(_ context.Context, wid models.WorkflowId, wf *models.Workflow, wfLogger models.WorkflowLogger) error {
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e.l.Info("setting up workflow", "wid", wid)
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setupStep := Step{name: "dummy setup", kind: models.StepKindSystem}
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const setupIdx = -1
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wfLogger.ControlWriter(setupIdx, setupStep, models.StepStatusStart).Write([]byte{0})
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defer wfLogger.ControlWriter(setupIdx, setupStep, models.StepStatusEnd).Write([]byte{0})
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fmt.Fprintf(wfLogger.DataWriter(setupIdx, "stdout"), "dummy engine: workflow %q ready", wf.Name)
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return nil
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}
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func (e *DummyEngine) WorkflowTimeout() time.Duration {
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return 5 * time.Minute
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}
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func (e *DummyEngine) DestroyWorkflow(_ context.Context, wid models.WorkflowId) error {
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e.l.Info("destroying workflow", "wid", wid)
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return nil
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}
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func (e *DummyEngine) RunStep(_ context.Context, wid models.WorkflowId, w *models.Workflow, idx int, _ []secrets.UnlockedSecret, wfLogger models.WorkflowLogger) error {
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step := w.Steps[idx]
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e.l.Info("running step", "wid", wid, "step", step.Name(), "command", step.Command())
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fmt.Fprintf(wfLogger.DataWriter(idx, "stdout"), "$ %s", step.Command())
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return nil
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}
+2
spindle/server.go
+2
spindle/server.go
···
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"tangled.org/core/spindle/config"
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"tangled.org/core/spindle/db"
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"tangled.org/core/spindle/engine"
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"tangled.org/core/spindle/engines/dummy"
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"tangled.org/core/spindle/engines/nixery"
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"tangled.org/core/spindle/models"
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"tangled.org/core/spindle/queue"
···
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s, err := New(ctx, cfg, map[string]models.Engine{
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"nixery": nixeryEng,
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"dummy": dummy.New(log.FromContext(ctx)),
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})
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if err != nil {
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return err