Documentation
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Overview ¶
Package output contains interfaces and implementations for Butler Outputs, which are responsible for delivering Butler protobufs to LogDog collection endpoints.
Output instance implementations must be goroutine-safe. The Butler may elect to output multiple messages at the same time.
The package current provides the following implementations:
- pubsub: Write logs to Google Cloud Pub/Sub.
- log: (Debug/testing) data is dumped to the installed Logger instance.
Index ¶
Constants ¶
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Variables ¶
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Functions ¶
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Types ¶
type Output ¶
type Output interface {
// SendBundle sends a constructed ButlerLogBundle through the Output.
//
// If an error is returned, it indicates a failure to send the bundle.
// If there is a data error or a message type is not supported by the
// Output, it should log the error and return nil.
SendBundle(*logpb.ButlerLogBundle) error
// MaxSendBundles is the number of concurrent calls to SendBundle allowed.
//
// If <= 0, only one SendBundle will be called at a time.
MaxSendBundles() int
// URLConstructionEnv should return a bootstrap.Environment containing
// any fields necessary for clients to construct a URL pointing to where this
// Output is sending its data.
//
// Returning an empty Environment means that clients will not be able to
// construct URLs to this data (which may be accurate, depending on the
// Output implementation).
//
// StreamServerURI is ignored and should not be specified.
//
// NOTE: This is an awful encapsulation violation. We should change the butler
// protocol so that opening a new stream has the butler immediately reply with
// the externally-visible URL to the stream and stop exporting these envvars
// entirely.
URLConstructionEnv() bootstrap.Environment
// MaxSize returns the maximum number of bytes that this Output can process
// with a single send. A return value <=0 indicates that there is no fixed
// maximum size for this Output.
//
// Since it is impossible for callers to know the actual size of the message
// that is being submitted, and since message batching may cluster across
// size boundaries, this should be a conservative estimate.
MaxSize() int
// Collect current Output stats.
Stats() Stats
// Close closes the Output, blocking until any buffered actions are flushed.
Close()
}
Output is a sink endpoint for groups of messages.
An Output's methods must be goroutine-safe.
Note that there is no guarantee that any of the bundles passed through an Output are ordered.
type Stats ¶
type Stats interface {
fmt.Stringer
// SentBytes returns the number of bytes
SentBytes() int64
// SentMessages returns the number of successfully transmitted messages.
SentMessages() int64
// DiscardedMessages returns the number of discarded messages.
DiscardedMessages() int64
// Errors returns the number of errors encountered during operation.
Errors() int64
}
Stats is an interface to query Output statistics.
An Output's ability to keep statistics varies with its implementation details. Currently, Stats are for debugging/information purposes only.
type StatsBase ¶
type StatsBase struct {
F struct {
SentBytes int64 // The number of bytes sent.
SentMessages int64 // The number of messages sent.
DiscardedMessages int64 // The number of messages that have been discarded.
Errors int64 // The number of errors encountered.
}
}
StatsBase is a simple implementation of the Stats interface.
func (*StatsBase) DiscardedMessages ¶
DiscardedMessages implements Stats.
func (*StatsBase) SentMessages ¶
SentMessages implements Stats.
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