Henry
c7cc92382b
Co-authored-by: nova28 <17953305+nova28@users.noreply.github.com> Co-authored-by: Carlos Florencio <carlosmflorencio@gmail.com>
52 lines
2.0 KiB
Go
52 lines
2.0 KiB
Go
// Package reachability sweeps every eligible SSH executor on a configurable
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// interval, probing each with bounded concurrency and persisting the result
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// through a hysteresis-owning write path. See
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// docs/specs/executors/system-design/ssh-reachability.md.
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package reachability
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import "time"
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const (
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// probeTimeout bounds a single probe's TCP dial and SSH handshake.
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// sshDialTimeout is 30s; a shorter bound here keeps one hung host from
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// holding a semaphore slot for half the interval.
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probeTimeout = 10 * time.Second
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// passConcurrency bounds simultaneous outbound connections and file
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// descriptors while keeping a pass short.
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passConcurrency = 4
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// failureThreshold is the smallest value that suppresses a single-probe
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// blip; worst-case detection is two intervals.
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failureThreshold = 2
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// DefaultIntervalSeconds is the effective interval used when the
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// configured value is absent, negative, fractional, or unparsable.
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DefaultIntervalSeconds = 60
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// MinIntervalSeconds and MaxIntervalSeconds bound the poller's cadence.
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// 0 is a separate "disabled" sentinel and is never clamped into this
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// range.
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MinIntervalSeconds = 15
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MaxIntervalSeconds = 3600
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)
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// ClampInterval applies this package's bounds to a raw configured interval
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// (in seconds) and reports whether the value was adjusted — worth one
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// startup log line rather than a refused boot. The environment path in
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// internal/common/config already normalizes an absent, empty, fractional, or
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// unparsable value to DefaultIntervalSeconds; a YAML value reaches here
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// unnormalized; either way this function still owns the below-minimum,
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// above-maximum, and negative cases directly.
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func ClampInterval(seconds int) (effective int, clamped bool) {
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switch {
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case seconds == 0:
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return 0, false
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case seconds < 0:
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return DefaultIntervalSeconds, true
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case seconds < MinIntervalSeconds:
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return MinIntervalSeconds, true
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case seconds > MaxIntervalSeconds:
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return MaxIntervalSeconds, true
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default:
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return seconds, false
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}
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}
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