Documentation
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Overview ¶
Package faults injects failures into the emulator's responses.
It exists so a test can prove its own error handling: a retry loop is only tested by a request that actually fails, and against a real cloud a failure is something you wait for rather than ask for.
Index ¶
Constants ¶
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Variables ¶
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Functions ¶
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Types ¶
type Rule ¶
type Rule struct {
// Method is an HTTP method, or empty for any.
Method string
// Path matches the escaped path. A trailing * makes it a prefix, so
// "/storage/v1/*" covers a whole service.
Path string
// Status is the HTTP status to answer with. Zero means 503.
Status int
// Code is the canonical error code. Zero is derived from Status.
Code gerr.Code
// Message is the error text. Empty gets a default naming the rule.
Message string
// Latency delays the response. It runs on the injected clock, so under a
// FakeClock the request waits until a test advances time.
Latency time.Duration
// Count is how many matching requests to fail. Zero means every one.
Count int
// Rate is the fraction of matching requests to fail, 0..1. Zero means every
// one. It is applied deterministically — a rate of 0.2 fails exactly one in
// every five matching requests, in a fixed pattern — so a fault composes
// with time travel into a reproducible test rather than a coin flip.
Rate float64
}
Rule decides which requests fail and how. A zero Method or Path matches anything, so the empty Rule matches every request.
func (Rule) FailsRequest ¶
FailsRequest reports whether a matched rule ends the request with an error. A latency-only rule — a delay with no error asked for — does not: it slows a request that then succeeds normally. Every other rule (an explicit status, or the bare rule with neither latency nor status) fails the request.
type Set ¶
type Set struct {
// contains filtered or unexported fields
}
Set is the live list of rules. It is safe for concurrent use: rules are added from a test goroutine while requests are being served.
func (*Set) Len ¶
Len reports how many rules are still armed, so a test can assert one fired as often as it expected.
func (*Set) Match ¶
Match returns the first rule claiming a request, consuming one of its firings. Exhausted rules are dropped, so a Count of 1 fails once and then lets the retry through.
func (*Set) Rules ¶
Rules returns a snapshot of the armed rules, for a status view. Order is arm order, which is match order.
func (*Set) UnaryServerInterceptor ¶
func (s *Set) UnaryServerInterceptor(clk clock.Clock) grpc.UnaryServerInterceptor
UnaryServerInterceptor applies the same rules to unary gRPC calls that the REST path applies to HTTP requests, so a single Set faults both protocols. The match is on the full method (/pkg.Service/Method), the latency runs on the injected clock, and the failure is a real gRPC status — the rule's canonical code, which gerr numbers the same as grpc/codes — not an HTTP status smuggled over gRPC. Streaming RPCs are not intercepted.
Source Files