129 lines
3.6 KiB
Go
129 lines
3.6 KiB
Go
package agent
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import (
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"bytes"
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"crypto/md5"
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"fmt"
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"math"
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"os"
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"os/user"
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"strconv"
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"time"
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"github.com/hashicorp/consul/types"
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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 cross 128 nodes,
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// another at 256, another at 512, etc. By 8192 nodes, we will scale up
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// by a factor of 8.
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//
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// If you update this, you may need to adjust the tuning of
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// CoordinateUpdatePeriod and CoordinateUpdateMaxBatchSize.
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aeScaleThreshold = 128
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)
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// msgpackHandle is a shared handle for encoding/decoding of
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// messages
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var msgpackHandle = &codec.MsgpackHandle{
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RawToString: true,
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WriteExt: true,
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}
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// aeScale is used to scale the time interval at which anti-entropy updates take
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// 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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// 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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// stringHash returns a simple md5sum for a string.
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func stringHash(s string) string {
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return fmt.Sprintf("%x", md5.Sum([]byte(s)))
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}
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// checkIDHash returns a simple md5sum for a types.CheckID.
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func checkIDHash(checkID types.CheckID) string {
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return stringHash(string(checkID))
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}
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// FilePermissions is an interface which allows a struct to set
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// ownership and permissions easily on a file it describes.
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type FilePermissions interface {
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// User returns a user ID or user name
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User() string
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// Group returns a group ID. Group names are not supported.
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Group() string
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// Mode returns a string of file mode bits e.g. "0644"
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Mode() string
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}
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// setFilePermissions handles configuring ownership and permissions settings
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// on a given file. It takes a path and any struct implementing the
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// FilePermissions interface. All permission/ownership settings are optional.
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// If no user or group is specified, the current user/group will be used. Mode
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// is optional, and has no default (the operation is not performed if absent).
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// User may be specified by name or ID, but group may only be specified by ID.
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func setFilePermissions(path string, p FilePermissions) error {
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var err error
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uid, gid := os.Getuid(), os.Getgid()
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if p.User() != "" {
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if uid, err = strconv.Atoi(p.User()); err == nil {
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goto GROUP
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}
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// Try looking up the user by name
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if u, err := user.Lookup(p.User()); err == nil {
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uid, _ = strconv.Atoi(u.Uid)
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goto GROUP
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}
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return fmt.Errorf("invalid user specified: %v", p.User())
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}
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GROUP:
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if p.Group() != "" {
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if gid, err = strconv.Atoi(p.Group()); err != nil {
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return fmt.Errorf("invalid group specified: %v", p.Group())
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}
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}
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if err := os.Chown(path, uid, gid); err != nil {
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return fmt.Errorf("failed setting ownership to %d:%d on %q: %s",
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uid, gid, path, err)
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}
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if p.Mode() != "" {
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mode, err := strconv.ParseUint(p.Mode(), 8, 32)
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if err != nil {
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return fmt.Errorf("invalid mode specified: %v", p.Mode())
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}
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if err := os.Chmod(path, os.FileMode(mode)); err != nil {
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return fmt.Errorf("failed setting permissions to %d on %q: %s",
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mode, path, err)
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}
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}
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return nil
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}
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