| 1 | package legatus |
| 2 | |
| 3 | import ( |
| 4 | "context" |
| 5 | "io" |
| 6 | "log/slog" |
| 7 | "sync" |
| 8 | "time" |
| 9 | |
| 10 | "go.bigb.es/auxilia/culpa" |
| 11 | "go.bigb.es/auxilia/scribe" |
| 12 | ) |
| 13 | |
| 14 | // Runner executes flows across an inventory. It pools one Conn per host and |
| 15 | // carries a SharedStore so sequential Run calls can pass data between groups |
| 16 | // (e.g. exits → relay). The Runner reaches hosts only through the Dialer/Conn |
| 17 | // interfaces, never SSH directly (IV1, PC1). |
| 18 | type Runner struct { |
| 19 | inv *Inventory |
| 20 | dialer Dialer |
| 21 | concurrency int |
| 22 | policy ErrorPolicy |
| 23 | reporter Reporter |
| 24 | prompter Prompter |
| 25 | logger *slog.Logger |
| 26 | dryRun bool |
| 27 | out io.Writer |
| 28 | |
| 29 | shared *SharedStore |
| 30 | |
| 31 | mu sync.Mutex |
| 32 | pool map[string]Conn |
| 33 | } |
| 34 | |
| 35 | // NewRunner builds a Runner. Defaults: concurrency 1, ContinueOnError, no-op |
| 36 | // reporter, non-interactive prompter, slog.Default logger. |
| 37 | func NewRunner(inv *Inventory, opts ...Option) *Runner { |
| 38 | r := &Runner{ |
| 39 | inv: inv, |
| 40 | concurrency: 1, |
| 41 | policy: ContinueOnError, |
| 42 | reporter: NopReporter{}, |
| 43 | prompter: DenyPrompter{}, |
| 44 | logger: slog.Default(), |
| 45 | out: io.Discard, |
| 46 | shared: NewSharedStore(), |
| 47 | pool: map[string]Conn{}, |
| 48 | } |
| 49 | for _, o := range opts { |
| 50 | o(r) |
| 51 | } |
| 52 | return r |
| 53 | } |
| 54 | |
| 55 | // Shared returns the cross-host store, persistent across Run calls. |
| 56 | func (r *Runner) Shared() *SharedStore { return r.shared } |
| 57 | |
| 58 | // Run executes flow against the hosts matching sel (all hosts if none), fanning |
| 59 | // out across an ordered worker pool capped at the configured concurrency. It |
| 60 | // always returns a result per host. Under FailFast, once a host fails the run |
| 61 | // context is cancelled and hosts not yet dispatched are recorded as cancelled |
| 62 | // without dialing — because jobs are fed in inventory order, with concurrency 1 |
| 63 | // this cancellation is deterministic. |
| 64 | func (r *Runner) Run(ctx context.Context, src FlowSource, sel ...Selector) RunResult { |
| 65 | flow, err := src.Resolve() |
| 66 | if err != nil { |
| 67 | rr := r.resolveFailure(flow.Name, err) |
| 68 | r.reporter.RunDone(rr) |
| 69 | return rr |
| 70 | } |
| 71 | |
| 72 | hosts := r.inv.Hosts(sel...) |
| 73 | results := make([]FlowResult, len(hosts)) |
| 74 | |
| 75 | conc := r.concurrency |
| 76 | if conc < 1 { |
| 77 | conc = 1 |
| 78 | } |
| 79 | if conc > len(hosts) { |
| 80 | conc = len(hosts) |
| 81 | } |
| 82 | |
| 83 | runCtx, cancel := context.WithCancel(ctx) |
| 84 | defer cancel() |
| 85 | |
| 86 | type job struct { |
| 87 | idx int |
| 88 | h *Host |
| 89 | } |
| 90 | jobs := make(chan job) |
| 91 | var wg sync.WaitGroup |
| 92 | var failOnce sync.Once |
| 93 | |
| 94 | for w := 0; w < conc; w++ { |
| 95 | wg.Add(1) |
| 96 | go func() { |
| 97 | defer wg.Done() |
| 98 | for j := range jobs { |
| 99 | fr := r.runHost(runCtx, flow, j.h) |
| 100 | results[j.idx] = fr |
| 101 | if r.policy == FailFast && fr.Status == StatusFailed { |
| 102 | failOnce.Do(cancel) |
| 103 | } |
| 104 | } |
| 105 | }() |
| 106 | } |
| 107 | |
| 108 | for i, h := range hosts { |
| 109 | if r.policy == FailFast { |
| 110 | select { |
| 111 | case <-runCtx.Done(): |
| 112 | results[i] = r.cancelledFlow(flow, h, runCtx.Err()) |
| 113 | continue |
| 114 | default: |
| 115 | } |
| 116 | } |
| 117 | jobs <- job{idx: i, h: h} |
| 118 | } |
| 119 | close(jobs) |
| 120 | wg.Wait() |
| 121 | |
| 122 | rr := RunResult{Flows: results} |
| 123 | r.reporter.RunDone(rr) |
| 124 | return rr |
| 125 | } |
| 126 | |
| 127 | // resolveFailure builds the RunResult for a FlowSource that failed to resolve |
| 128 | // before any host fan-out: a single host-less FlowResult carrying the error under |
| 129 | // a synthetic "resolve" step, so RunResult.Failed() is true and the error reaches |
| 130 | // the caller through the same res.Failed() path as a step failure. |
| 131 | func (r *Runner) resolveFailure(name string, err error) RunResult { |
| 132 | sr := StepResult{Step: "resolve", Status: StatusFailed, Err: err, Started: time.Now()} |
| 133 | fr := FlowResult{Flow: name, Steps: []StepResult{sr}, Status: StatusFailed, Params: map[string]any{}} |
| 134 | return RunResult{Flows: []FlowResult{fr}} |
| 135 | } |
| 136 | |
| 137 | func (r *Runner) cancelledFlow(flow Flow, h *Host, err error) FlowResult { |
| 138 | sr := StepResult{Step: "cancelled", Status: StatusFailed, Err: err, Started: time.Now()} |
| 139 | return FlowResult{Flow: flow.Name, Host: h.Name, Steps: []StepResult{sr}, Status: StatusFailed, Params: map[string]any{}} |
| 140 | } |
| 141 | |
| 142 | func (r *Runner) runHost(ctx context.Context, flow Flow, h *Host) FlowResult { |
| 143 | hlog := r.logger.With("host", h.Name, "flow", flow.Name) |
| 144 | r.reporter.FlowStart(h.Name, flow.Name) |
| 145 | fr := FlowResult{Flow: flow.Name, Host: h.Name} |
| 146 | |
| 147 | conn, err := r.connFor(ctx, h) |
| 148 | if err != nil { |
| 149 | err = culpa.Wrap(err, "dial host "+h.Name) |
| 150 | sr := StepResult{Step: "dial", Status: StatusFailed, Err: err, Started: time.Now()} |
| 151 | hlog.Error("dial failed", scribe.Err(err)) |
| 152 | r.reporter.StepDone(h.Name, sr) |
| 153 | fr.Steps = append(fr.Steps, sr) |
| 154 | fr.Status = StatusFailed |
| 155 | fr.Params = map[string]any{} |
| 156 | r.reporter.FlowDone(h.Name, fr) |
| 157 | return fr |
| 158 | } |
| 159 | |
| 160 | fc := NewFlowCtx(ctx, h, conn, |
| 161 | WithFlowLogger(hlog), |
| 162 | WithFlowDryRun(r.dryRun), |
| 163 | WithFlowPrompter(r.prompter), |
| 164 | WithFlowShared(r.shared), |
| 165 | WithFlowOutput(r.out), |
| 166 | ) |
| 167 | |
| 168 | for _, step := range flow.Steps { |
| 169 | sr := r.runStep(fc, hlog, h.Name, step) |
| 170 | // Record change before the next step's Check so later steps can gate on it |
| 171 | // (steps.When/OnChanged); WouldChange counts so gates fire in dry-run too. |
| 172 | fc.setChanged(sr.Step, sr.Status == StatusChanged || sr.Status == StatusWouldChange) |
| 173 | fr.Steps = append(fr.Steps, sr) |
| 174 | if sr.Status == StatusFailed { |
| 175 | break // fail-fast within a flow (IV7) |
| 176 | } |
| 177 | } |
| 178 | fr.Status = aggregate(fr.Steps) |
| 179 | fr.Params = fc.snapshot() |
| 180 | r.reporter.FlowDone(h.Name, fr) |
| 181 | return fr |
| 182 | } |
| 183 | |
| 184 | // runStep runs one step's check/apply lifecycle, emitting structured logs and |
| 185 | // reporter events with no step-author involvement (PC5). |
| 186 | func (r *Runner) runStep(fc *FlowCtx, hlog *slog.Logger, host string, step Step) StepResult { |
| 187 | name := step.Name() |
| 188 | slogger := hlog.With("step", name) |
| 189 | fc.log = slogger // per-step tag; params and other fields persist across steps |
| 190 | r.reporter.StepStart(host, name) |
| 191 | |
| 192 | started := time.Now() |
| 193 | slogger.Debug("step starting") |
| 194 | sr := StepResult{Step: name, Started: started} |
| 195 | |
| 196 | need, err := step.Check(fc) |
| 197 | if err != nil { |
| 198 | sr.Status = StatusFailed |
| 199 | sr.Err = culpa.Wrap(err, "check "+name) |
| 200 | sr.Duration = time.Since(started) |
| 201 | slogger.Error("step failed", "stage", "check", scribe.Err(sr.Err)) |
| 202 | r.reporter.StepDone(host, sr) |
| 203 | return sr |
| 204 | } |
| 205 | slogger.Debug("check complete", "need", need) |
| 206 | |
| 207 | if !need { |
| 208 | sr.Status = StatusSkipped |
| 209 | sr.Duration = time.Since(started) |
| 210 | slogger.Info("step skipped") |
| 211 | r.reporter.StepDone(host, sr) |
| 212 | return sr |
| 213 | } |
| 214 | if fc.dryRun { |
| 215 | sr.Status = StatusWouldChange |
| 216 | sr.Duration = time.Since(started) |
| 217 | slogger.Info("step would change (dry-run)") |
| 218 | r.reporter.StepDone(host, sr) |
| 219 | return sr |
| 220 | } |
| 221 | |
| 222 | out, err := step.Apply(fc) |
| 223 | sr.Duration = time.Since(started) |
| 224 | if err != nil { |
| 225 | sr.Status = StatusFailed |
| 226 | sr.Err = culpa.Wrap(err, "apply "+name) |
| 227 | slogger.Error("step failed", "stage", "apply", scribe.Err(sr.Err)) |
| 228 | r.reporter.StepDone(host, sr) |
| 229 | return sr |
| 230 | } |
| 231 | sr.Outcome = out |
| 232 | if out.Changed { |
| 233 | sr.Status = StatusChanged |
| 234 | } else { |
| 235 | sr.Status = StatusOK |
| 236 | } |
| 237 | slogger.Info("step applied", "status", sr.Status.String(), "changed", out.Changed, "dur", sr.Duration) |
| 238 | r.reporter.StepDone(host, sr) |
| 239 | return sr |
| 240 | } |
| 241 | |
| 242 | func (r *Runner) connFor(ctx context.Context, h *Host) (Conn, error) { |
| 243 | r.mu.Lock() |
| 244 | c, ok := r.pool[h.Name] |
| 245 | r.mu.Unlock() |
| 246 | if ok { |
| 247 | return c, nil |
| 248 | } |
| 249 | if r.dialer == nil { |
| 250 | return nil, culpa.WithCode(culpa.New("legatus: no dialer configured"), "LEGATUS_NO_DIALER") |
| 251 | } |
| 252 | c, err := r.dialer.Dial(ctx, h) |
| 253 | if err != nil { |
| 254 | return nil, err |
| 255 | } |
| 256 | r.mu.Lock() |
| 257 | if existing, ok := r.pool[h.Name]; ok { // lost a race; keep the first |
| 258 | r.mu.Unlock() |
| 259 | _ = c.Close() |
| 260 | return existing, nil |
| 261 | } |
| 262 | r.pool[h.Name] = c |
| 263 | r.mu.Unlock() |
| 264 | return c, nil |
| 265 | } |
| 266 | |
| 267 | // Close closes all pooled connections. It also satisfies steward's Stopper. |
| 268 | func (r *Runner) Close() error { |
| 269 | r.mu.Lock() |
| 270 | defer r.mu.Unlock() |
| 271 | var firstErr error |
| 272 | for name, c := range r.pool { |
| 273 | if err := c.Close(); err != nil && firstErr == nil { |
| 274 | firstErr = culpa.Wrap(err, "close conn "+name) |
| 275 | } |
| 276 | delete(r.pool, name) |
| 277 | } |
| 278 | return firstErr |
| 279 | } |
| 280 | |
| 281 | // Stop closes pooled connections (steward Stopper). |
| 282 | func (r *Runner) Stop(context.Context) error { return r.Close() } |
| 283 | |