| 1 | package steps |
| 2 | |
| 3 | import ( |
| 4 | "bytes" |
| 5 | "path" |
| 6 | "strings" |
| 7 | |
| 8 | "go.bigb.es/auxilia/culpa" |
| 9 | "go.bigb.es/auxilia/legatus" |
| 10 | ) |
| 11 | |
| 12 | // ValidatedFile writes a file only after a validator command passes against the |
| 13 | // exact bytes to be installed. It stages the content beside the target, runs the |
| 14 | // validator on the staged path, and commits with an atomic same-directory move |
| 15 | // on success; on failure the staged file is removed and the live target is left |
| 16 | // untouched. Use it for configs that must pass a checker before a reload |
| 17 | // (sing-box check -c, haproxy -c -f). Unlike File, it supports sudo writes. |
| 18 | type ValidatedFile struct { |
| 19 | Path string |
| 20 | Content []byte |
| 21 | Mode legatus.FileMode |
| 22 | Owner string |
| 23 | Sudo bool |
| 24 | // Validator returns the command that validates the staged file at the given |
| 25 | // path; a non-zero exit aborts the write. It runs with Sudo when Sudo is set. |
| 26 | Validator func(stagedPath string) legatus.Cmd |
| 27 | } |
| 28 | |
| 29 | // Name returns the step name. |
| 30 | func (f ValidatedFile) Name() string { return "validated-file:" + f.Path } |
| 31 | |
| 32 | // Check reuses File's content+mode hash idempotency: a remote file already |
| 33 | // matching the desired content and mode needs no change (and so no validation). |
| 34 | func (f ValidatedFile) Check(fc *legatus.FlowCtx) (bool, error) { |
| 35 | match, err := fileMatches(fc, f.Path, f.Content, f.Mode) |
| 36 | if err != nil { |
| 37 | return false, err |
| 38 | } |
| 39 | return !match, nil |
| 40 | } |
| 41 | |
| 42 | // Apply stages the content beside the target, validates the staged path, and on |
| 43 | // success moves it into place; on validator failure it removes the staged file |
| 44 | // and errors, leaving the live target unchanged. |
| 45 | func (f ValidatedFile) Apply(fc *legatus.FlowCtx) (legatus.Outcome, error) { |
| 46 | if f.Validator == nil { |
| 47 | return legatus.Outcome{}, culpa.WithCode( |
| 48 | culpa.Errorf("validated-file %s: no Validator set", f.Path), "VALIDATED_FILE") |
| 49 | } |
| 50 | staged := stagedPath(f.Path) |
| 51 | |
| 52 | var putOpts []legatus.PutOption |
| 53 | if f.Sudo { |
| 54 | putOpts = append(putOpts, legatus.WithPutSudo()) |
| 55 | } |
| 56 | if err := fc.Conn().Put(fc.Ctx(), bytes.NewReader(f.Content), staged, f.Mode, putOpts...); err != nil { |
| 57 | return legatus.Outcome{}, culpa.WithCode(culpa.Wrapf(err, "stage %s", staged), "VALIDATED_FILE") |
| 58 | } |
| 59 | |
| 60 | vcmd := f.Validator(staged) |
| 61 | vcmd.Sudo = vcmd.Sudo || f.Sudo |
| 62 | res, err := fc.Conn().Exec(fc.Ctx(), vcmd) |
| 63 | if err != nil { |
| 64 | f.cleanup(fc, staged) |
| 65 | return legatus.Outcome{}, culpa.WithCode(culpa.Wrapf(err, "validate %s", f.Path), "VALIDATED_FILE") |
| 66 | } |
| 67 | if res.ExitCode != 0 { |
| 68 | f.cleanup(fc, staged) |
| 69 | return legatus.Outcome{}, culpa.WithCode( |
| 70 | culpa.Errorf("validated-file %s: validation failed: exit %d: %s", |
| 71 | f.Path, res.ExitCode, strings.TrimSpace(string(res.Combined()))), "VALIDATED_FILE") |
| 72 | } |
| 73 | |
| 74 | if err := f.run(fc, legatus.Cmd{Path: "mv", Args: []string{staged, f.Path}, Sudo: f.Sudo}); err != nil { |
| 75 | f.cleanup(fc, staged) |
| 76 | return legatus.Outcome{}, culpa.WithCode(culpa.Wrapf(err, "commit %s", f.Path), "VALIDATED_FILE") |
| 77 | } |
| 78 | if f.Owner != "" { |
| 79 | if err := f.run(fc, legatus.Cmd{Path: "chown", Args: []string{f.Owner, f.Path}, Sudo: f.Sudo}); err != nil { |
| 80 | return legatus.Outcome{}, culpa.WithCode(culpa.Wrapf(err, "chown %s", f.Path), "VALIDATED_FILE") |
| 81 | } |
| 82 | } |
| 83 | return legatus.Outcome{Changed: true, Message: "validated + wrote " + f.Path}, nil |
| 84 | } |
| 85 | |
| 86 | // run executes an Apply-path command that must succeed, turning a non-zero exit |
| 87 | // into an error. |
| 88 | func (f ValidatedFile) run(fc *legatus.FlowCtx, cmd legatus.Cmd) error { |
| 89 | res, err := fc.Conn().Exec(fc.Ctx(), cmd) |
| 90 | if err != nil { |
| 91 | return err |
| 92 | } |
| 93 | if res.ExitCode != 0 { |
| 94 | return culpa.Errorf("%s exit %d: %s", cmd.Path, res.ExitCode, strings.TrimSpace(string(res.Combined()))) |
| 95 | } |
| 96 | return nil |
| 97 | } |
| 98 | |
| 99 | // cleanup removes the staged file after a failed validation or commit. A cleanup |
| 100 | // error is deliberately not returned so the original failure is the one surfaced |
| 101 | // (mirrors the transport's staging-cleanup on error paths). |
| 102 | func (f ValidatedFile) cleanup(fc *legatus.FlowCtx, staged string) { |
| 103 | _, _ = fc.Conn().Exec(fc.Ctx(), legatus.Cmd{Path: "rm", Args: []string{"-f", staged}, Sudo: f.Sudo}) |
| 104 | } |
| 105 | |
| 106 | // stagedPath derives a dotfile staging path beside p — same directory, so the |
| 107 | // commit move is atomic on the target filesystem. |
| 108 | func stagedPath(p string) string { |
| 109 | dir, base := path.Split(p) |
| 110 | return dir + "." + base + ".legatus-new" |
| 111 | } |
| 112 | |