Files
mesh-catalog/modules/pacman/cmd/pacman-tools/upgrade_health.go
T

239 lines
8.7 KiB
Go

package main
// The module's health, read from the bus (novox/hq ADR 0508 §11; issue 1579). The health check of the keeper's
// process reads this node's latest run, the week's round and any held kernel from the module's states, never a
// unit's age, so a laptop that slept through a run, or a node that was off, is judged by what the bus holds. It
// is unhealthy, naming why, when:
//
// - `installed.<node>` is marked not current (ADR 0507 §2);
// - no `upgrade-order` is set: no round starts, and every node says so (ADR 0508 §5);
// - the node's latest run was refused, failed, or its after-upgrade check did not pass, until a later run passes;
// - the latest run's transaction goes on past RunLimit: hung, holding pacman's lock;
// - the latest run held a kernel, naming the package, the DKMS module and its bound (ADR 0508 §3);
// - the week's round stands still: this node's turn came more than round-start-minutes ago and it has not
// started, or the node it waits for stalled or failed, named with since when (ADR 0508 §6).
//
// A state that cannot be read is unhealthy: failure is loud.
import (
"encoding/json"
"errors"
"fmt"
"os"
"sort"
"strings"
"time"
)
// Health is the module's health, as the node-engine asks it (novox/hq ADR 0240): unhealthy with why.
type Health struct {
Healthy bool `json:"healthy"`
Why string `json:"why"`
Found []string `json:"found,omitempty"`
}
// RunLimit is how long a run's transaction may go on before it is unhealthy. A transaction has no timeout on
// purpose: killing pacman in the middle of one leaves a half-upgraded machine. One past the limit is a hung one
// (a stuck hook, a stalled download), which holds pacman's database lock so no later run can start; it is said,
// not killed.
const RunLimit = 2 * time.Hour
// healthTime is how the health writes a moment: the machine's local time.
const healthTime = "2006-01-02 15:04 MST"
// keeperConfig is the keeper's config as the tools bundle reads it, from the file the manifest names to the
// bundle too (EnvConfig); a test replaces it. A file that cannot be read is an empty config: no order.
var keeperConfig = func() KeeperConfig {
var c KeeperConfig
if raw, err := os.ReadFile(os.Getenv(EnvConfig)); err == nil {
_ = json.Unmarshal(raw, &c)
}
return c
}
// readOnly is a state the tools bundle reads, as the round's readers take it; it writes nothing.
type readOnly struct{ StateReader }
var errReadOnly = errors.New("the health writes nothing")
func (readOnly) Create(string, any) (uint64, error) { return 0, errReadOnly }
func (readOnly) Update(string, any, uint64) (uint64, error) { return 0, errReadOnly }
func (readOnly) Put(string, any) (uint64, error) { return 0, errReadOnly }
func (readOnly) Delete(string) error { return errReadOnly }
// UpgradeHealth is the health of this node's upgrades, from the module's states.
func (m *Machine) UpgradeHealth() Health {
if h, said := m.InstalledHealth(); said {
return h
}
if m.States == nil || m.Node == "" {
return Health{Why: "the tools bundle was started without its node (MESH_NODE) or the bus: the upgrades cannot be read"}
}
cfg := keeperConfig()
if len(cfg.UpgradeOrder) == 0 {
return Health{Why: "no upgrade-order is set: no node upgrades, since no round starts until the mesh-level key " +
"upgrade-order names the nodes in the order they upgrade (ADR 0508 §5)"}
}
runs := readOnly{m.States(StateRuns)}
latest, err := latestOwnRun(runs, m.Node)
if err != nil {
return Health{Why: "the node's runs could not be read: " + err.Error()}
}
if latest != nil {
if h, said := m.runHealth(*latest); said {
return h
}
}
if h, said := m.roundHealth(readOnly{m.States(StateRounds)}, runs, cfg.RoundStartMinutes); said {
return h
}
if latest == nil {
return Health{Healthy: true, Why: "no upgrade has run on this node through the mesh yet"}
}
return Health{Healthy: true, Why: fmt.Sprintf("the last run, %s, passed its after-upgrade check", latest.Run)}
}
// latestOwnRun is the node's newest run that the mesh ran, or nil; runs read from pacman's log are history.
func latestOwnRun(runs Bucket, node string) (*Run, error) {
keys, err := runs.Keys()
if err != nil {
return nil, err
}
sort.Sort(sort.Reverse(sort.StringSlice(keys)))
for _, k := range keys {
if !strings.HasPrefix(k, node+".") {
continue
}
e, err := runs.Get(k)
if err != nil {
return nil, err
}
if e == nil {
continue
}
var r Run
if err := json.Unmarshal(e.Value, &r); err != nil {
return nil, fmt.Errorf("run %s: %w", k, err)
}
if r.From == FromLog || len(r.Steps) == 0 {
continue
}
return &r, nil
}
return nil, nil
}
// runHealth judges the node's latest run; said is false when the run has nothing to say against the node.
func (m *Machine) runHealth(r Run) (Health, bool) {
var held []HeldKernel
var started *Step
for i, s := range r.Steps {
switch s.Step {
case StepCheckedBefore:
held = s.Held
case StepStarted:
started = &r.Steps[i]
}
}
what := r.Kind + " run " + r.Run
last := r.Steps[len(r.Steps)-1]
switch lastStep(r) {
case StepRefused:
return Health{Why: fmt.Sprintf("the %s did not start (%s): %s", what, last.At.Local().Format(healthTime), last.Why)}, true
case StepCheckedAfter:
if last.Check == nil || !last.Check.Passed {
why := fmt.Sprintf("the %s did not pass its after-upgrade check (%s)", what, last.At.Local().Format(healthTime))
for _, s := range r.Steps {
if s.Step == StepFailed {
why += ": its transaction failed: " + s.Error
}
}
if last.Check != nil {
for _, u := range last.Check.Unbuilt {
why += fmt.Sprintf("; %s %s is not built for kernel %s", u.Module, u.Version, u.Kernel)
}
}
return Health{Why: why + "; pacman_upgrades with the node and the run says it whole", Found: []string{r.Run}}, true
}
case StepStarted:
if started != nil && m.Now().Sub(started.At) > RunLimit {
return Health{Why: fmt.Sprintf("the %s's transaction (%s) has gone on since %s, longer than %s: it is hung, and holds pacman's database lock so no later run can start",
what, started.Unit, started.At.Local().Format(healthTime), RunLimit)}, true
}
}
if len(held) > 0 {
var said []string
for _, h := range held {
said = append(said, fmt.Sprintf("%s %s (the DKMS module %s allows %s)", h.Package, h.Version, h.Module, h.Bound))
}
return Health{Why: "the " + what + " held back " + strings.Join(said, ", ") + ": the kernel waits until its DKMS module follows (ADR 0508 §3)"}, true
}
return Health{}, false
}
// roundHealth judges this node's place in the newest round; said is false when the round has nothing to say
// against it.
func (m *Machine) roundHealth(rounds, runs Bucket, startMinutes int) (Health, bool) {
id, err := latestRound(rounds)
if err != nil {
return Health{Why: "the rounds could not be read: " + err.Error()}, true
}
if id == "" {
return Health{}, false
}
v, err := readRound(rounds, runs, id)
if err != nil {
return Health{Why: "round " + id + " could not be read: " + err.Error()}, true
}
if v == nil || !contains(v.Round.Order, m.Node) {
return Health{}, false
}
if startMinutes < 1 {
startMinutes = defaultRoundStartMinutes
}
byNode := map[string]NodeInRound{}
for _, s := range RoundState(v, m.Now(), startMinutes) {
byNode[s.Node] = s
}
since := func(s NodeInRound) string {
if s.Since == nil {
return "an unknown time"
}
return s.Since.Local().Format(healthTime)
}
me := byNode[m.Node]
switch me.State {
case InRoundStalled:
return Health{Why: fmt.Sprintf("round %s: this node's turn came at %s and it has not started its run within %d minutes", id, since(me), startMinutes)}, true
case InRoundWaiting:
if w, ok := byNode[me.WaitsFor]; ok {
switch w.State {
case InRoundStalled:
return Health{Why: fmt.Sprintf("round %s stands still: this node waits for %s, whose turn came at %s and which has not started (since %s)", id, w.Node, since(w), since(w))}, true
case InRoundFailed:
return Health{Why: fmt.Sprintf("round %s stopped at %s, whose run or check failed at %s: this node waits on it since then; only the operator passes it (pacman_round with pass and a reason)", id, w.Node, since(w))}, true
}
}
}
return Health{}, false
}
// lastError is the last line pacman marked as an error, else the last line the journal holds; a journal that
// could not be read says so in one line starting with "(", which is no error to name.
func lastError(journal []string) string {
last := ""
for _, l := range journal {
l = strings.TrimSpace(l)
if l == "" || strings.HasPrefix(l, "(the journal could not be read") {
continue
}
last = l
}
for i := len(journal) - 1; i >= 0; i-- {
if l := strings.TrimSpace(journal[i]); strings.HasPrefix(l, "error:") {
return l
}
}
return last
}