94 lines
2.2 KiB
Go
94 lines
2.2 KiB
Go
package agent
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import (
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"bytes"
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crand "crypto/rand"
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"fmt"
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"math"
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"math/rand"
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"os"
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"os/exec"
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"runtime"
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"time"
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"github.com/hashicorp/go-msgpack/codec"
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)
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const (
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// This scale factor means we will add a minute after we
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// cross 128 nodes, another at 256, another at 512, etc.
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// By 8192 nodes, we will scale up by a factor of 8
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aeScaleThreshold = 128
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)
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// aeScale is used to scale the time interval at which anti-entropy
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// take place. It is used to prevent saturation as the cluster size grows
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func aeScale(interval time.Duration, n int) time.Duration {
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// Don't scale until we cross the threshold
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if n <= aeScaleThreshold {
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return interval
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}
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multiplier := math.Ceil(math.Log2(float64(n))-math.Log2(aeScaleThreshold)) + 1.0
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return time.Duration(multiplier) * interval
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}
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// Returns a random stagger interval between 0 and the duration
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func randomStagger(intv time.Duration) time.Duration {
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return time.Duration(uint64(rand.Int63()) % uint64(intv))
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}
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// strContains checks if a list contains a string
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func strContains(l []string, s string) bool {
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for _, v := range l {
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if v == s {
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return true
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}
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}
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return false
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}
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// ExecScript returns a command to execute a script
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func ExecScript(script string) (*exec.Cmd, error) {
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var shell, flag string
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if runtime.GOOS == "windows" {
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shell = "cmd"
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flag = "/C"
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} else {
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shell = "/bin/sh"
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flag = "-c"
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}
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if other := os.Getenv("SHELL"); other != "" {
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shell = other
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}
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cmd := exec.Command(shell, flag, script)
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return cmd, nil
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}
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// generateUUID is used to generate a random UUID
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func generateUUID() string {
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buf := make([]byte, 16)
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if _, err := crand.Read(buf); err != nil {
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panic(fmt.Errorf("failed to read random bytes: %v", err))
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}
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return fmt.Sprintf("%08x-%04x-%04x-%04x-%12x",
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buf[0:4],
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buf[4:6],
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buf[6:8],
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buf[8:10],
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buf[10:16])
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}
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// decodeMsgPack is used to decode a MsgPack encoded object
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func decodeMsgPack(buf []byte, out interface{}) error {
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return codec.NewDecoder(bytes.NewReader(buf), msgpackHandle).Decode(out)
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}
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// encodeMsgPack is used to encode an object with msgpack
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func encodeMsgPack(msg interface{}) ([]byte, error) {
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var buf bytes.Buffer
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err := codec.NewEncoder(&buf, msgpackHandle).Encode(msg)
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return buf.Bytes(), err
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}
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