forked from hashicorp/serf
/
ipc.go
1033 lines (865 loc) · 23.3 KB
/
ipc.go
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package agent
/*
The agent exposes an IPC mechanism that is used for both controlling
Serf as well as providing a fast streaming mechanism for events. This
allows other applications to easily leverage Serf as the event layer.
We additionally make use of the IPC layer to also handle RPC calls from
the CLI to unify the code paths. This results in a split Request/Response
as well as streaming mode of operation.
The system is fairly simple, each client opens a TCP connection to the
agent. The connection is initialized with a handshake which establishes
the protocol version being used. This is to allow for future changes to
the protocol.
Once initialized, clients send commands and wait for responses. Certain
commands will cause the client to subscribe to events, and those will be
pushed down the socket as they are received. This provides a low-latency
mechanism for applications to send and receive events, while also providing
a flexible control mechanism for Serf.
*/
import (
"bufio"
"fmt"
"github.com/armon/go-metrics"
"github.com/hashicorp/logutils"
"github.com/hashicorp/serf/serf"
"github.com/ugorji/go/codec"
"io"
"log"
"net"
"os"
"regexp"
"strings"
"sync"
"sync/atomic"
"time"
)
const (
MinIPCVersion = 1
MaxIPCVersion = 1
)
const (
handshakeCommand = "handshake"
eventCommand = "event"
forceLeaveCommand = "force-leave"
joinCommand = "join"
membersCommand = "members"
membersFilteredCommand = "members-filtered"
streamCommand = "stream"
stopCommand = "stop"
monitorCommand = "monitor"
leaveCommand = "leave"
installKeyCommand = "install-key"
useKeyCommand = "use-key"
removeKeyCommand = "remove-key"
listKeysCommand = "list-keys"
tagsCommand = "tags"
queryCommand = "query"
respondCommand = "respond"
authCommand = "auth"
statsCommand = "stats"
)
const (
unsupportedCommand = "Unsupported command"
unsupportedIPCVersion = "Unsupported IPC version"
duplicateHandshake = "Handshake already performed"
handshakeRequired = "Handshake required"
monitorExists = "Monitor already exists"
invalidFilter = "Invalid event filter"
streamExists = "Stream with given sequence exists"
invalidQueryID = "No pending queries matching ID"
authRequired = "Authentication required"
invalidAuthToken = "Invalid authentication token"
)
const (
queryRecordAck = "ack"
queryRecordResponse = "response"
queryRecordDone = "done"
)
// Request header is sent before each request
type requestHeader struct {
Command string
Seq uint64
}
// Response header is sent before each response
type responseHeader struct {
Seq uint64
Error string
}
type handshakeRequest struct {
Version int32
}
type authRequest struct {
AuthKey string
}
type eventRequest struct {
Name string
Payload []byte
Coalesce bool
}
type forceLeaveRequest struct {
Node string
}
type joinRequest struct {
Existing []string
Replay bool
}
type joinResponse struct {
Num int32
}
type membersFilteredRequest struct {
Tags map[string]string
Status string
Name string
}
type membersResponse struct {
Members []Member
}
type keyRequest struct {
Key string
}
type keyResponse struct {
Messages map[string]string
Keys map[string]int
NumNodes int
NumErr int
NumResp int
}
type monitorRequest struct {
LogLevel string
}
type streamRequest struct {
Type string
}
type stopRequest struct {
Stop uint64
}
type tagsRequest struct {
Tags map[string]string
DeleteTags []string
}
type queryRequest struct {
FilterNodes []string
FilterTags map[string]string
RequestAck bool
Timeout time.Duration
Name string
Payload []byte
}
type respondRequest struct {
ID uint64
Payload []byte
}
type queryRecord struct {
Type string
From string
Payload []byte
}
type logRecord struct {
Log string
}
type userEventRecord struct {
Event string
LTime serf.LamportTime
Name string
Payload []byte
Coalesce bool
}
type queryEventRecord struct {
Event string
ID uint64 // ID is opaque to client, used to respond
LTime serf.LamportTime
Name string
Payload []byte
}
type Member struct {
Name string
Addr net.IP
Port uint16
Tags map[string]string
Status string
ProtocolMin uint8
ProtocolMax uint8
ProtocolCur uint8
DelegateMin uint8
DelegateMax uint8
DelegateCur uint8
}
type memberEventRecord struct {
Event string
Members []Member
}
type AgentIPC struct {
sync.Mutex
agent *Agent
authKey string
clients map[string]*IPCClient
listener net.Listener
logger *log.Logger
logWriter *logWriter
stop bool
stopCh chan struct{}
}
type IPCClient struct {
queryID uint64 // Used to increment query IDs
name string
conn net.Conn
reader *bufio.Reader
writer *bufio.Writer
dec *codec.Decoder
enc *codec.Encoder
writeLock sync.Mutex
version int32 // From the handshake, 0 before
logStreamer *logStream
eventStreams map[uint64]*eventStream
pendingQueries map[uint64]*serf.Query
queryLock sync.Mutex
didAuth bool // Did we get an auth token yet?
}
// send is used to send an object using the MsgPack encoding. send
// is serialized to prevent write overlaps, while properly buffering.
func (c *IPCClient) Send(header *responseHeader, obj interface{}) error {
c.writeLock.Lock()
defer c.writeLock.Unlock()
if err := c.enc.Encode(header); err != nil {
return err
}
if obj != nil {
if err := c.enc.Encode(obj); err != nil {
return err
}
}
if err := c.writer.Flush(); err != nil {
return err
}
return nil
}
func (c *IPCClient) String() string {
return fmt.Sprintf("ipc.client: %v", c.conn.RemoteAddr())
}
// nextQueryID safely generates a new query ID
func (c *IPCClient) nextQueryID() uint64 {
return atomic.AddUint64(&c.queryID, 1)
}
// RegisterQuery is used to register a pending query that may
// get a response. The ID of the query is returned
func (c *IPCClient) RegisterQuery(q *serf.Query) uint64 {
// Generate a unique-per-client ID
id := c.nextQueryID()
// Ensure the query deadline is in the future
timeout := q.Deadline().Sub(time.Now())
if timeout < 0 {
return id
}
// Register the query
c.queryLock.Lock()
c.pendingQueries[id] = q
c.queryLock.Unlock()
// Setup a timer to deregister after the timeout
time.AfterFunc(timeout, func() {
c.queryLock.Lock()
delete(c.pendingQueries, id)
c.queryLock.Unlock()
})
return id
}
// NewAgentIPC is used to create a new Agent IPC handler
func NewAgentIPC(agent *Agent, authKey string, listener net.Listener,
logOutput io.Writer, logWriter *logWriter) *AgentIPC {
if logOutput == nil {
logOutput = os.Stderr
}
ipc := &AgentIPC{
agent: agent,
authKey: authKey,
clients: make(map[string]*IPCClient),
listener: listener,
logger: log.New(logOutput, "", log.LstdFlags),
logWriter: logWriter,
stopCh: make(chan struct{}),
}
go ipc.listen()
return ipc
}
// Shutdown is used to shutdown the IPC layer
func (i *AgentIPC) Shutdown() {
i.Lock()
defer i.Unlock()
if i.stop {
return
}
i.stop = true
close(i.stopCh)
i.listener.Close()
// Close the existing connections
for _, client := range i.clients {
client.conn.Close()
}
}
// listen is a long running routine that listens for new clients
func (i *AgentIPC) listen() {
for {
conn, err := i.listener.Accept()
if err != nil {
if i.stop {
return
}
i.logger.Printf("[ERR] agent.ipc: Failed to accept client: %v", err)
continue
}
i.logger.Printf("[INFO] agent.ipc: Accepted client: %v", conn.RemoteAddr())
metrics.IncrCounter([]string{"agent", "ipc", "accept"}, 1)
// Wrap the connection in a client
client := &IPCClient{
name: conn.RemoteAddr().String(),
conn: conn,
reader: bufio.NewReader(conn),
writer: bufio.NewWriter(conn),
eventStreams: make(map[uint64]*eventStream),
pendingQueries: make(map[uint64]*serf.Query),
}
client.dec = codec.NewDecoder(client.reader,
&codec.MsgpackHandle{RawToString: true, WriteExt: true})
client.enc = codec.NewEncoder(client.writer,
&codec.MsgpackHandle{RawToString: true, WriteExt: true})
if err != nil {
i.logger.Printf("[ERR] agent.ipc: Failed to create decoder: %v", err)
conn.Close()
continue
}
// Register the client
i.Lock()
if !i.stop {
i.clients[client.name] = client
go i.handleClient(client)
} else {
conn.Close()
}
i.Unlock()
}
}
// deregisterClient is called to cleanup after a client disconnects
func (i *AgentIPC) deregisterClient(client *IPCClient) {
// Close the socket
client.conn.Close()
// Remove from the clients list
i.Lock()
delete(i.clients, client.name)
i.Unlock()
// Remove from the log writer
if client.logStreamer != nil {
i.logWriter.DeregisterHandler(client.logStreamer)
client.logStreamer.Stop()
}
// Remove from event handlers
for _, es := range client.eventStreams {
i.agent.DeregisterEventHandler(es)
es.Stop()
}
}
// handleClient is a long running routine that handles a single client
func (i *AgentIPC) handleClient(client *IPCClient) {
defer i.deregisterClient(client)
var reqHeader requestHeader
for {
// Decode the header
if err := client.dec.Decode(&reqHeader); err != nil {
if !i.stop {
// The second part of this if is to block socket
// errors from Windows which appear to happen every
// time there is an EOF.
if err != io.EOF && !strings.Contains(err.Error(), "WSARecv") {
i.logger.Printf("[ERR] agent.ipc: failed to decode request header: %v", err)
}
}
return
}
// Evaluate the command
if err := i.handleRequest(client, &reqHeader); err != nil {
i.logger.Printf("[ERR] agent.ipc: Failed to evaluate request: %v", err)
return
}
}
}
// handleRequest is used to evaluate a single client command
func (i *AgentIPC) handleRequest(client *IPCClient, reqHeader *requestHeader) error {
// Look for a command field
command := reqHeader.Command
seq := reqHeader.Seq
// Ensure the handshake is performed before other commands
if command != handshakeCommand && client.version == 0 {
respHeader := responseHeader{Seq: seq, Error: handshakeRequired}
client.Send(&respHeader, nil)
return fmt.Errorf(handshakeRequired)
}
metrics.IncrCounter([]string{"agent", "ipc", "command"}, 1)
// Ensure the client has authenticated after the handshake if necessary
if i.authKey != "" && !client.didAuth && command != authCommand && command != handshakeCommand {
i.logger.Printf("[WARN] agent.ipc: Client sending commands before auth")
respHeader := responseHeader{Seq: seq, Error: authRequired}
client.Send(&respHeader, nil)
return nil
}
// Dispatch command specific handlers
switch command {
case handshakeCommand:
return i.handleHandshake(client, seq)
case authCommand:
return i.handleAuth(client, seq)
case eventCommand:
return i.handleEvent(client, seq)
case membersCommand, membersFilteredCommand:
return i.handleMembers(client, command, seq)
case streamCommand:
return i.handleStream(client, seq)
case monitorCommand:
return i.handleMonitor(client, seq)
case stopCommand:
return i.handleStop(client, seq)
case forceLeaveCommand:
return i.handleForceLeave(client, seq)
case joinCommand:
return i.handleJoin(client, seq)
case leaveCommand:
return i.handleLeave(client, seq)
case installKeyCommand:
return i.handleInstallKey(client, seq)
case useKeyCommand:
return i.handleUseKey(client, seq)
case removeKeyCommand:
return i.handleRemoveKey(client, seq)
case listKeysCommand:
return i.handleListKeys(client, seq)
case tagsCommand:
return i.handleTags(client, seq)
case queryCommand:
return i.handleQuery(client, seq)
case respondCommand:
return i.handleRespond(client, seq)
case statsCommand:
return i.handleStats(client, seq)
default:
respHeader := responseHeader{Seq: seq, Error: unsupportedCommand}
client.Send(&respHeader, nil)
return fmt.Errorf("command '%s' not recognized", command)
}
}
func (i *AgentIPC) handleHandshake(client *IPCClient, seq uint64) error {
var req handshakeRequest
if err := client.dec.Decode(&req); err != nil {
return fmt.Errorf("decode failed: %v", err)
}
resp := responseHeader{
Seq: seq,
Error: "",
}
// Check the version
if req.Version < MinIPCVersion || req.Version > MaxIPCVersion {
resp.Error = unsupportedIPCVersion
} else if client.version != 0 {
resp.Error = duplicateHandshake
} else {
client.version = req.Version
}
return client.Send(&resp, nil)
}
func (i *AgentIPC) handleAuth(client *IPCClient, seq uint64) error {
var req authRequest
if err := client.dec.Decode(&req); err != nil {
return fmt.Errorf("decode failed: %v", err)
}
resp := responseHeader{
Seq: seq,
Error: "",
}
// Check the token matches
if req.AuthKey == i.authKey {
client.didAuth = true
} else {
resp.Error = invalidAuthToken
}
return client.Send(&resp, nil)
}
func (i *AgentIPC) handleEvent(client *IPCClient, seq uint64) error {
var req eventRequest
if err := client.dec.Decode(&req); err != nil {
return fmt.Errorf("decode failed: %v", err)
}
// Attempt the send
err := i.agent.UserEvent(req.Name, req.Payload, req.Coalesce)
// Respond
resp := responseHeader{
Seq: seq,
Error: errToString(err),
}
return client.Send(&resp, nil)
}
func (i *AgentIPC) handleForceLeave(client *IPCClient, seq uint64) error {
var req forceLeaveRequest
if err := client.dec.Decode(&req); err != nil {
return fmt.Errorf("decode failed: %v", err)
}
// Attempt leave
err := i.agent.ForceLeave(req.Node)
// Respond
resp := responseHeader{
Seq: seq,
Error: errToString(err),
}
return client.Send(&resp, nil)
}
func (i *AgentIPC) handleJoin(client *IPCClient, seq uint64) error {
var req joinRequest
if err := client.dec.Decode(&req); err != nil {
return fmt.Errorf("decode failed: %v", err)
}
// Attempt the join
num, err := i.agent.Join(req.Existing, req.Replay)
// Respond
header := responseHeader{
Seq: seq,
Error: errToString(err),
}
resp := joinResponse{
Num: int32(num),
}
return client.Send(&header, &resp)
}
func (i *AgentIPC) handleMembers(client *IPCClient, command string, seq uint64) error {
serf := i.agent.Serf()
raw := serf.Members()
members := make([]Member, 0, len(raw))
if command == membersFilteredCommand {
var req membersFilteredRequest
err := client.dec.Decode(&req)
if err != nil {
return fmt.Errorf("decode failed: %v", err)
}
raw, err = i.filterMembers(raw, req.Tags, req.Status, req.Name)
if err != nil {
return err
}
}
for _, m := range raw {
sm := Member{
Name: m.Name,
Addr: m.Addr,
Port: m.Port,
Tags: m.Tags,
Status: m.Status.String(),
ProtocolMin: m.ProtocolMin,
ProtocolMax: m.ProtocolMax,
ProtocolCur: m.ProtocolCur,
DelegateMin: m.DelegateMin,
DelegateMax: m.DelegateMax,
DelegateCur: m.DelegateCur,
}
members = append(members, sm)
}
header := responseHeader{
Seq: seq,
Error: "",
}
resp := membersResponse{
Members: members,
}
return client.Send(&header, &resp)
}
func (i *AgentIPC) filterMembers(members []serf.Member, tags map[string]string,
status string, name string) ([]serf.Member, error) {
result := make([]serf.Member, 0, len(members))
// Pre-compile all the regular expressions
tagsRe := make(map[string]*regexp.Regexp)
for tag, expr := range tags {
re, err := regexp.Compile(fmt.Sprintf("^%s$", expr))
if err != nil {
return nil, fmt.Errorf("Failed to compile regex: %v", err)
}
tagsRe[tag] = re
}
statusRe, err := regexp.Compile(fmt.Sprintf("^%s$", status))
if err != nil {
return nil, fmt.Errorf("Failed to compile regex: %v", err)
}
nameRe, err := regexp.Compile(fmt.Sprintf("^%s$", name))
if err != nil {
return nil, fmt.Errorf("Failed to compile regex: %v", err)
}
OUTER:
for _, m := range members {
// Check if tags were passed, and if they match
for tag := range tags {
if !tagsRe[tag].MatchString(m.Tags[tag]) {
continue OUTER
}
}
// Check if status matches
if status != "" && !statusRe.MatchString(m.Status.String()) {
continue
}
// Check if node name matches
if name != "" && !nameRe.MatchString(m.Name) {
continue
}
// Made it past the filters!
result = append(result, m)
}
return result, nil
}
func (i *AgentIPC) handleInstallKey(client *IPCClient, seq uint64) error {
var req keyRequest
if err := client.dec.Decode(&req); err != nil {
return fmt.Errorf("decode failed: %v", err)
}
queryResp, err := i.agent.InstallKey(req.Key)
header := responseHeader{
Seq: seq,
Error: errToString(err),
}
resp := keyResponse{
Messages: queryResp.Messages,
NumNodes: queryResp.NumNodes,
NumErr: queryResp.NumErr,
NumResp: queryResp.NumResp,
}
return client.Send(&header, &resp)
}
func (i *AgentIPC) handleUseKey(client *IPCClient, seq uint64) error {
var req keyRequest
if err := client.dec.Decode(&req); err != nil {
return fmt.Errorf("decode failed: %v", err)
}
queryResp, err := i.agent.UseKey(req.Key)
header := responseHeader{
Seq: seq,
Error: errToString(err),
}
resp := keyResponse{
Messages: queryResp.Messages,
NumNodes: queryResp.NumNodes,
NumErr: queryResp.NumErr,
NumResp: queryResp.NumResp,
}
return client.Send(&header, &resp)
}
func (i *AgentIPC) handleRemoveKey(client *IPCClient, seq uint64) error {
var req keyRequest
if err := client.dec.Decode(&req); err != nil {
return fmt.Errorf("decode failed: %v", err)
}
queryResp, err := i.agent.RemoveKey(req.Key)
header := responseHeader{
Seq: seq,
Error: errToString(err),
}
resp := keyResponse{
Messages: queryResp.Messages,
NumNodes: queryResp.NumNodes,
NumErr: queryResp.NumErr,
NumResp: queryResp.NumResp,
}
return client.Send(&header, &resp)
}
func (i *AgentIPC) handleListKeys(client *IPCClient, seq uint64) error {
queryResp, err := i.agent.ListKeys()
header := responseHeader{
Seq: seq,
Error: errToString(err),
}
resp := keyResponse{
Messages: queryResp.Messages,
Keys: queryResp.Keys,
NumNodes: queryResp.NumNodes,
NumErr: queryResp.NumErr,
NumResp: queryResp.NumResp,
}
return client.Send(&header, &resp)
}
func (i *AgentIPC) handleStream(client *IPCClient, seq uint64) error {
var es *eventStream
var req streamRequest
if err := client.dec.Decode(&req); err != nil {
return fmt.Errorf("decode failed: %v", err)
}
resp := responseHeader{
Seq: seq,
Error: "",
}
// Create the event filters
filters := ParseEventFilter(req.Type)
for _, f := range filters {
if !f.Valid() {
resp.Error = invalidFilter
goto SEND
}
}
// Check if there is an existing stream
if _, ok := client.eventStreams[seq]; ok {
resp.Error = streamExists
goto SEND
}
// Create an event streamer
es = newEventStream(client, filters, seq, i.logger)
client.eventStreams[seq] = es
// Register with the agent. Defer so that we can respond before
// registration, avoids any possible race condition
defer i.agent.RegisterEventHandler(es)
SEND:
return client.Send(&resp, nil)
}
func (i *AgentIPC) handleMonitor(client *IPCClient, seq uint64) error {
var req monitorRequest
if err := client.dec.Decode(&req); err != nil {
return fmt.Errorf("decode failed: %v", err)
}
resp := responseHeader{
Seq: seq,
Error: "",
}
// Upper case the log level
req.LogLevel = strings.ToUpper(req.LogLevel)
// Create a level filter
filter := LevelFilter()
filter.MinLevel = logutils.LogLevel(req.LogLevel)
if !ValidateLevelFilter(filter.MinLevel, filter) {
resp.Error = fmt.Sprintf("Unknown log level: %s", filter.MinLevel)
goto SEND
}
// Check if there is an existing monitor
if client.logStreamer != nil {
resp.Error = monitorExists
goto SEND
}
// Create a log streamer
client.logStreamer = newLogStream(client, filter, seq, i.logger)
// Register with the log writer. Defer so that we can respond before
// registration, avoids any possible race condition
defer i.logWriter.RegisterHandler(client.logStreamer)
SEND:
return client.Send(&resp, nil)
}
func (i *AgentIPC) handleStop(client *IPCClient, seq uint64) error {
var req stopRequest
if err := client.dec.Decode(&req); err != nil {
return fmt.Errorf("decode failed: %v", err)
}
// Remove a log monitor if any
if client.logStreamer != nil && client.logStreamer.seq == req.Stop {
i.logWriter.DeregisterHandler(client.logStreamer)
client.logStreamer.Stop()
client.logStreamer = nil
}
// Remove an event stream if any
if es, ok := client.eventStreams[req.Stop]; ok {
i.agent.DeregisterEventHandler(es)
es.Stop()
delete(client.eventStreams, req.Stop)
}
// Always succeed
resp := responseHeader{Seq: seq, Error: ""}
return client.Send(&resp, nil)
}
func (i *AgentIPC) handleLeave(client *IPCClient, seq uint64) error {
i.logger.Printf("[INFO] agent.ipc: Graceful leave triggered")
// Do the leave
err := i.agent.Leave()
if err != nil {
i.logger.Printf("[ERR] agent.ipc: leave failed: %v", err)
}
resp := responseHeader{Seq: seq, Error: errToString(err)}
// Send and wait
err = client.Send(&resp, nil)
// Trigger a shutdown!
if err := i.agent.Shutdown(); err != nil {
i.logger.Printf("[ERR] agent.ipc: shutdown failed: %v", err)
}
return err
}
func (i *AgentIPC) handleTags(client *IPCClient, seq uint64) error {
var req tagsRequest
if err := client.dec.Decode(&req); err != nil {
return fmt.Errorf("decode failed: %v", err)
}
tags := make(map[string]string)
for key, val := range i.agent.SerfConfig().Tags {
var delTag bool
for _, delkey := range req.DeleteTags {
delTag = (delTag || delkey == key)
}
if !delTag {
tags[key] = val
}
}
for key, val := range req.Tags {
tags[key] = val
}
err := i.agent.SetTags(tags)
resp := responseHeader{Seq: seq, Error: errToString(err)}
return client.Send(&resp, nil)
}
func (i *AgentIPC) handleQuery(client *IPCClient, seq uint64) error {
var req queryRequest
if err := client.dec.Decode(&req); err != nil {
return fmt.Errorf("decode failed: %v", err)
}
// Setup the query
params := serf.QueryParam{
FilterNodes: req.FilterNodes,
FilterTags: req.FilterTags,
RequestAck: req.RequestAck,
Timeout: req.Timeout,
}
// Start the query
queryResp, err := i.agent.Query(req.Name, req.Payload, ¶ms)
// Stream the query responses
if err == nil {
qs := newQueryResponseStream(client, seq, i.logger)
defer func() {
go qs.Stream(queryResp)
}()
}
// Respond
resp := responseHeader{
Seq: seq,
Error: errToString(err),
}
return client.Send(&resp, nil)
}
func (i *AgentIPC) handleRespond(client *IPCClient, seq uint64) error {
var req respondRequest
if err := client.dec.Decode(&req); err != nil {
return fmt.Errorf("decode failed: %v", err)
}
// Lookup the query
client.queryLock.Lock()
query, ok := client.pendingQueries[req.ID]
client.queryLock.Unlock()