Documentation
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Overview ¶
Package fault decides what a failure is allowed to say to a caller.
Both transports face the same question and have to answer it the same way: which failures are the caller's to see, and which arrive wrapped around something that is not -- the path of a profile lock, a filesystem location. Keeping that decision here is the point. Three copies of it had already grown, they disagreed, and where they disagreed one of them leaked.
Index ¶
Constants ¶
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Variables ¶
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Functions ¶
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Types ¶
type Kind ¶
type Kind int
Kind is what sort of failure it was, so a transport can say so in its own vocabulary.
const ( // Internal is a failure the caller can do nothing about, and whose detail is // not theirs to see. It is the default precisely because it is the safe one: // anything this package has not been taught to recognise is treated as // carrying internals until it is. Internal Kind = iota // Invalid is a request that was wrong. Sending it again will not help. Invalid // Missing is a post, account or list that X had nothing on. Missing // Refused is a write the gate turned down. Refused // LoginRequired is a session that needs signing in. LoginRequired // Paced is a budget that has been spent. Paced // Busy is the profile held by a login or a write, or a shutdown underway. // Temporary, and worth trying again. Busy // Timeout is work that did not finish inside the caller's budget. Timeout // NotApplied is a write that was carried out and that X did not apply. The // distinction from Internal matters: the machinery worked, so the caller has // a real answer rather than a fault to report. NotApplied )
func Describe ¶
Describe reports what kind of failure err was and what may be said about it.
The message is that of the error that was recognised, never the one it arrived wrapped in. A profile already in use, for instance, is reported by the sentinel that says so and not by the wrapper carrying the path of its lock.
A nil error is Internal with no message; callers are expected to check for success before asking.
Two things this does not do. It trusts the message of an error it recognises: whoever builds one is responsible for it holding nothing internal, and the types exist so that is a deliberate act rather than a wrapper's accident. And its precedence is the order below, which matters only for an error satisfying two cases at once -- nothing builds one today, and the order says an outcome X reported beats a deadline that also passed, because the outcome is the more specific answer.
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