Files
releases/server/buffer.go
T
Torin Sandall 05e9eb601c Refactor diagnostics support in server and runtime
- These changes update the server to always report performance metrics
  and the remote client address. The metrics are cheap to compute and
  there is no significant reason to require more complex configuration
  at this point.

- These changes update the runtime to allow callers to supply the
  diagnostics buffer implementation. This way callers can hook up their
  own sinks to the server's diagnostics.
2017-09-19 15:54:26 -07:00

96 lines
2.0 KiB
Go

// Copyright 2017 The OPA Authors. All rights reserved.
// Use of this source code is governed by an Apache2
// license that can be found in the LICENSE file.
package server
import (
"sync"
"time"
"github.com/open-policy-agent/opa/metrics"
"github.com/open-policy-agent/opa/topdown"
)
// Buffer defines an interface that the server can call to push diagnostic
// information about policy decisions. Buffers must be able to handle
// concurrent calls.
type Buffer interface {
// Push adds the given Info into the buffer.
Push(*Info)
// Iter iterates over the buffer, from oldest present Info to newest. It should
// call fn on each Info.
Iter(fn func(*Info))
}
// buffer stores diagnostic information.
type buffer struct {
ring []*Info
size int
start int // The index of the next item to pop.
end int // The index where the next item will be inserted.
sync.Mutex
}
// NewBoundedBuffer creates a new Buffer with maximum size n. NewBoundedBuffer
// will panic if n is not positive.
func NewBoundedBuffer(n int) Buffer {
if n <= 0 {
panic("size must be greater than 0")
}
return &buffer{ring: make([]*Info, n, n)}
}
func (b *buffer) Push(i *Info) {
b.Lock()
defer b.Unlock()
b.ring[b.end] = i
b.end = (b.end + 1) % len(b.ring)
switch b.size {
case len(b.ring): // We erased something, move the start up.
b.start = (b.start + 1) % len(b.ring)
default:
b.size++
}
}
func (b *buffer) Iter(fn func(*Info)) {
b.Lock()
defer b.Unlock()
i := b.start
for j := 0; j < b.size; j++ {
fn(b.ring[i])
i = (i + 1) % len(b.ring)
}
}
// Info contains information describing a policy decision.
type Info struct {
DecisionID string
RemoteAddr string
Query string
Timestamp time.Time
Input interface{}
Results *interface{}
Error error
Metrics metrics.Metrics
Trace []*topdown.Event
}
type diagSettings struct {
on bool
explain bool
}
var (
diagsOff = diagSettings{}
diagsOn = diagSettings{on: true}
diagsAll = diagSettings{on: true, explain: true}
)