99 lines
2.8 KiB
Go
99 lines
2.8 KiB
Go
package raft
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import (
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"bytes"
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"encoding/json"
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"io/ioutil"
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)
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// ReadPeersJSON consumes a legacy peers.json file in the format of the old JSON
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// peer store and creates a new-style configuration structure. This can be used
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// to migrate this data or perform manual recovery when running protocol versions
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// that can interoperate with older, unversioned Raft servers. This should not be
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// used once server IDs are in use, because the old peers.json file didn't have
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// support for these, nor non-voter suffrage types.
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func ReadPeersJSON(path string) (Configuration, error) {
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// Read in the file.
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buf, err := ioutil.ReadFile(path)
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if err != nil {
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return Configuration{}, err
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}
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// Parse it as JSON.
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var peers []string
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dec := json.NewDecoder(bytes.NewReader(buf))
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if err := dec.Decode(&peers); err != nil {
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return Configuration{}, err
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}
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// Map it into the new-style configuration structure. We can only specify
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// voter roles here, and the ID has to be the same as the address.
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var configuration Configuration
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for _, peer := range peers {
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server := Server{
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Suffrage: Voter,
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ID: ServerID(peer),
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Address: ServerAddress(peer),
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}
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configuration.Servers = append(configuration.Servers, server)
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}
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// We should only ingest valid configurations.
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if err := checkConfiguration(configuration); err != nil {
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return Configuration{}, err
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}
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return configuration, nil
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}
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// configEntry is used when decoding a new-style peers.json.
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type configEntry struct {
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// ID is the ID of the server (a UUID, usually).
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ID ServerID `json:"id"`
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// Address is the host:port of the server.
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Address ServerAddress `json:"address"`
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// NonVoter controls the suffrage. We choose this sense so people
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// can leave this out and get a Voter by default.
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NonVoter bool `json:"non_voter"`
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}
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// ReadConfigJSON reads a new-style peers.json and returns a configuration
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// structure. This can be used to perform manual recovery when running protocol
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// versions that use server IDs.
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func ReadConfigJSON(path string) (Configuration, error) {
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// Read in the file.
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buf, err := ioutil.ReadFile(path)
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if err != nil {
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return Configuration{}, err
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}
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// Parse it as JSON.
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var peers []configEntry
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dec := json.NewDecoder(bytes.NewReader(buf))
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if err := dec.Decode(&peers); err != nil {
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return Configuration{}, err
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}
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// Map it into the new-style configuration structure.
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var configuration Configuration
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for _, peer := range peers {
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suffrage := Voter
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if peer.NonVoter {
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suffrage = Nonvoter
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}
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server := Server{
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Suffrage: suffrage,
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ID: peer.ID,
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Address: peer.Address,
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}
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configuration.Servers = append(configuration.Servers, server)
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}
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// We should only ingest valid configurations.
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if err := checkConfiguration(configuration); err != nil {
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return Configuration{}, err
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}
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return configuration, nil
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}
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