Documentation
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Overview ¶
Package inventory keeps each host's cached instance inventory warm by refreshing it on a schedule, so UI/API reads are served without a live podman sweep and an unreachable host never stalls a request.
Index ¶
Constants ¶
This section is empty.
Variables ¶
This section is empty.
Functions ¶
func EffectiveStatsTimeout ¶ added in v1.0.29
EffectiveStatsTimeout maps a configured stats timeout to the value the poller will actually spend: anything <= 0 means defaultStatsTimeout, never "no timeout" (tick blocks the ticker, so an unbounded stats call would hang the whole poll loop) and never "expire instantly".
Exported because the zero-defaulting is not an internal detail: anything reasoning about the per-host budget from the outside — server's startup check that Timeout+StatsTimeout stays under Interval — has to reason about the same effective value, or a bare -container-stats-timeout=0 passes a check the poller then violates by 5s.
Types ¶
type Poller ¶
type Poller struct {
Svc Refresher
Interval time.Duration
Timeout time.Duration
// Stats, when non-nil, samples container resource usage on every tick,
// alongside the inventory refresh. Its failures are logged and otherwise
// ignored: reachability is the inventory refresh's to decide, and the
// Grafana alert rules all gate on podman_api_host_reachable.
Stats StatsRefresher
// StatsTimeout bounds one host's stats sample, independently of Timeout.
// Zero means defaultStatsTimeout — never "no timeout", so a caller that
// forgets to set it cannot hand the sampler an unbounded call. See tick for
// why this is a separate budget rather than a share of Timeout (#212).
StatsTimeout time.Duration
// contains filtered or unexported fields
}
Poller periodically refreshes every host's inventory into the service cache. It mirrors internal/prune.Scheduler: an immediate first pass so a fresh start warms within one cycle, per-tick panic recovery, a per-host timeout so one hung host can't bleed into the next cycle, and Wait() for clean shutdown.
func (*Poller) Start ¶
Start launches the ticker loop until ctx is cancelled. hostsFn returns the current host ids on each tick (so SIGHUP host reloads are picked up).
func (*Poller) StartVolumeUsage ¶ added in v1.0.28
func (p *Poller) StartVolumeUsage(ctx context.Context, hostsFn func() []string, r VolumeUsageRefresher, interval, timeout time.Duration)
StartVolumeUsage runs a separate, much slower loop that sizes each host's volumes. It is deliberately NOT part of tick(): podman's system df walks the whole store and can take minutes, so it must never delay an inventory refresh. Failures leave the previous sizing in place; staleness surfaces as podman_api_volume_usage_age_seconds rather than as a gap. It touches no reachability state, for the same reason the stats sampler doesn't.
type Refresher ¶
Refresher refreshes one host's cached inventory. Implemented by *instance.Service.RefreshHost.
type StatsRefresher ¶ added in v1.0.28
type StatsRefresher interface {
RefreshHostStats(ctx context.Context, host string) error
// DropHostStats discards the host's cached samples. Called when the host is
// not going to be sampled at all. No context: it does no I/O.
DropHostStats(host string)
}
StatsRefresher samples one host's container resource usage, or retires the samples it already holds. Implemented by *instance.Service.
Both methods are required, not optional: a sampler that can be skipped but not retired freezes a down host's series at their last value. Keeping them on one interface makes that a compile error rather than a silent metrics bug.
Source Files