jschoubben
39d5b25f95
mesh/merge-gate pass: builds restic → ace, g14, novox, shanks; no bus step; every machine composes with the change as it did without (4 of 4 compose)
mesh/repo-check pass: its merge-check.sh passed, each part in its toolchain: merge-check.sh (go), merge-check-typescript.sh (typescript)
mesh/delivery superseded: a newer head of the same pull request
The keep-daily, keep-weekly and keep-monthly preferences default to today's 14, 8 and 6. The night reads them from a file in its state and refuses anything but a count from 1 to 9999: it then thins nothing and says which setting is wrong, never handing a raw value to restic.
84 lines
2.9 KiB
Go
84 lines
2.9 KiB
Go
package main
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// The retention as a preference (novox/hq issue 416, ADR 0262). The mesh writes the settings
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// keep-daily, keep-weekly and keep-monthly into RetentionFile in this module's state, each defaulting
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// to today's rotation, so a machine that sets none thins exactly as before. The controller does not
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// type a setting yet (ADR 0164 is proposed), so this program is where a bad value is caught: it is
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// refused here and never handed to restic (issue 346: a raw setting is an injection point).
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import (
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"errors"
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"fmt"
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"os"
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"path/filepath"
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"regexp"
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"strconv"
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"strings"
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)
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// Retention is how many restore points each period keeps.
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type Retention struct{ Daily, Weekly, Monthly int }
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// TodaysRetention is the rotation before it was a preference (novox/hq ADR 0214), and still the
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// manifest's default.
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var TodaysRetention = Retention{14, 8, 6}
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// RetentionFile is the file the mesh writes the retention into, in this module's state.
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const RetentionFile = "retention.conf"
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// A count from 1 to 9999 with no leading zero: 0 would make restic ignore the period, and a number
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// past four digits is a typo, not a policy.
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var count = regexp.MustCompile(`^[1-9][0-9]{0,3}$`)
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// ParseRetention reads daily=, weekly= and monthly=, each once and each a count; anything else is
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// refused naming the setting it came from.
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func ParseRetention(text string) (Retention, error) {
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settingOf := map[string]string{"daily": "keep-daily", "weekly": "keep-weekly", "monthly": "keep-monthly"}
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seen := map[string]int{}
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for _, l := range strings.Split(text, "\n") {
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l = strings.TrimSpace(l)
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if l == "" || strings.HasPrefix(l, "#") {
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continue
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}
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k, v, ok := strings.Cut(l, "=")
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if !ok {
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return Retention{}, fmt.Errorf("%q is not key=value", l)
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}
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k, v = strings.TrimSpace(k), strings.TrimSpace(v)
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setting, known := settingOf[k]
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switch {
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case !known:
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return Retention{}, fmt.Errorf("%q is no retention this module reads (daily, weekly, monthly)", k)
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case seen[k] != 0:
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return Retention{}, fmt.Errorf("%s is given twice", k)
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case !count.MatchString(v):
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return Retention{}, fmt.Errorf("the %s setting is %q; it is a count from 1 to 9999", setting, v)
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}
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seen[k], _ = strconv.Atoi(v)
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}
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for _, k := range []string{"daily", "weekly", "monthly"} {
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if seen[k] == 0 {
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return Retention{}, fmt.Errorf("the %s setting is missing", settingOf[k])
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}
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}
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return Retention{seen["daily"], seen["weekly"], seen["monthly"]}, nil
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}
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// retention is this machine's: today's where the module was placed by a definition older than the
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// file, else what the file says.
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func (b *Backups) retention() (Retention, error) {
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path := filepath.Join(b.Where.State, RetentionFile)
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raw, err := os.ReadFile(path)
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if errors.Is(err, os.ErrNotExist) {
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return TodaysRetention, nil
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}
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if err != nil {
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return Retention{}, err
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}
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r, err := ParseRetention(string(raw))
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if err != nil {
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return Retention{}, fmt.Errorf("%s: %w", path, err)
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}
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return r, nil
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}
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