| 1 | package steps |
| 2 | |
| 3 | import ( |
| 4 | "strings" |
| 5 | |
| 6 | "go.bigb.es/auxilia/culpa" |
| 7 | "go.bigb.es/auxilia/legatus" |
| 8 | ) |
| 9 | |
| 10 | // Exec runs a command with idempotency guards. Check evaluates the guards |
| 11 | // (PC4); Apply runs the command. Guards (highest precedence first): |
| 12 | // - Creates: skip when the path already exists. |
| 13 | // - Unless: skip when the shell command exits 0. |
| 14 | // - OnlyIf: skip when the shell command exits non-zero. |
| 15 | // |
| 16 | // With no guard, the command always runs. |
| 17 | type Exec struct { |
| 18 | Cmd string |
| 19 | Args []string |
| 20 | Creates string |
| 21 | Unless string |
| 22 | OnlyIf string |
| 23 | Sudo bool |
| 24 | } |
| 25 | |
| 26 | // Name returns the step name. |
| 27 | func (e Exec) Name() string { return "exec:" + e.Cmd } |
| 28 | |
| 29 | // Check evaluates the guards and reports whether the command should run. |
| 30 | func (e Exec) Check(fc *legatus.FlowCtx) (bool, error) { |
| 31 | if e.Creates != "" { |
| 32 | res, err := fc.Conn().Exec(fc.Ctx(), legatus.Cmd{Path: "test", Args: []string{"-e", e.Creates}, Sudo: e.Sudo}) |
| 33 | if err != nil { |
| 34 | return false, culpa.WithCode(culpa.Wrapf(err, "creates guard %s", e.Creates), "EXEC_GUARD") |
| 35 | } |
| 36 | if res.ExitCode == 0 { |
| 37 | return false, nil // target exists ⇒ nothing to do. |
| 38 | } |
| 39 | } |
| 40 | |
| 41 | if e.Unless != "" { |
| 42 | code, err := runGuard(fc.Ctx(), fc.Conn(), e.Unless, e.Sudo) |
| 43 | if err != nil { |
| 44 | return false, err |
| 45 | } |
| 46 | if code == 0 { |
| 47 | return false, nil // unless succeeded ⇒ skip. |
| 48 | } |
| 49 | } |
| 50 | |
| 51 | if e.OnlyIf != "" { |
| 52 | code, err := runGuard(fc.Ctx(), fc.Conn(), e.OnlyIf, e.Sudo) |
| 53 | if err != nil { |
| 54 | return false, err |
| 55 | } |
| 56 | if code != 0 { |
| 57 | return false, nil // onlyif failed ⇒ skip. |
| 58 | } |
| 59 | } |
| 60 | |
| 61 | return true, nil |
| 62 | } |
| 63 | |
| 64 | // Apply runs the command and reports it changed state. |
| 65 | func (e Exec) Apply(fc *legatus.FlowCtx) (legatus.Outcome, error) { |
| 66 | res, err := fc.Conn().Exec(fc.Ctx(), legatus.Cmd{Path: e.Cmd, Args: e.Args, Sudo: e.Sudo}) |
| 67 | if err != nil { |
| 68 | return legatus.Outcome{}, culpa.WithCode(culpa.Wrapf(err, "exec %s", e.Cmd), "EXEC_RUN") |
| 69 | } |
| 70 | if res.ExitCode != 0 { |
| 71 | return legatus.Outcome{}, culpa.WithCode( |
| 72 | culpa.Errorf("exec %s: exit %d: %s", e.Cmd, res.ExitCode, strings.TrimSpace(string(res.Combined()))), |
| 73 | "EXEC_RUN") |
| 74 | } |
| 75 | return legatus.Outcome{Changed: true, Message: "ran " + e.Cmd, Data: res}, nil |
| 76 | } |
| 77 | |