mokhtar
e4c34784c8
the oneshot+timer produced 8367 journal lines a day of systemd start/stop noise. now Type=notify with an internal ticker, logging transitions only. hardware sits behind sensor.Sensor; internal/monitor is pure, so the shutdown state machine is tested without a pi. four guards, each tested, because a false poweroff of a box with no physical access is worse than a missed one: - a failed read resets the arming window rather than pausing it - voltage must actually fall across the window, else it is a stuck sensor. this is the only defence against the ac line reading 0 while mains is connected, so it is load-bearing - a settle period stops a restart loop acting on early readings - flapping ac cannot accumulate verified on hardware 2026-08-09: after poweroff on battery the x1208 starts the pi again when mains returns, with no button press. that was the risk that could have made this feature unsafe. a failed tick rewrites the previous sample with sensor_healthy 0 and the failure counter, so last_update still freezes for the staleness alert while the failure stays visible. module path moved to git.mial.net. debian units and the compose overlay deleted; deployment lives in the infra repo.
27 lines
845 B
Go
27 lines
845 B
Go
// Package sensor defines the hardware seam. Everything above this interface is
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// pure and testable on any machine; everything below it touches the Pi.
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package sensor
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import "time"
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// Reading is one complete sample. A Reading only exists if every channel was
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// read successfully — there is no partial Reading, because a partial sample
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// cannot be reasoned about downstream.
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type Reading struct {
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ACPresent bool
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Volts float64
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SOC float64
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At time.Time
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}
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// Sensor reads the UPS. Read returns an error if any channel fails; callers
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// must treat the Reading as invalid in that case.
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//
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// Implementations may hold OS handles open across calls. A Read that returns
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// an error must leave the Sensor usable: the next Read reacquires whatever it
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// needs.
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type Sensor interface {
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Read() (Reading, error)
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Close() error
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}
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