135 lines
3 KiB
Go
135 lines
3 KiB
Go
package nomad
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import (
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"context"
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"fmt"
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"net"
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"sync"
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"time"
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"github.com/hashicorp/nomad/helper/pool"
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"github.com/hashicorp/nomad/helper/tlsutil"
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"github.com/hashicorp/raft"
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)
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// RaftLayer implements the raft.StreamLayer interface,
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// so that we can use a single RPC layer for Raft and Nomad
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type RaftLayer struct {
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// Addr is the listener address to return
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addr net.Addr
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// connCh is used to accept connections
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connCh chan net.Conn
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// TLS wrapper
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tlsWrap tlsutil.Wrapper
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tlsWrapLock sync.RWMutex
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// Tracks if we are closed
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closed bool
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closeCh chan struct{}
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closeLock sync.Mutex
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}
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// NewRaftLayer is used to initialize a new RaftLayer which can
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// be used as a StreamLayer for Raft. If a tlsConfig is provided,
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// then the connection will use TLS.
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func NewRaftLayer(addr net.Addr, tlsWrap tlsutil.Wrapper) *RaftLayer {
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layer := &RaftLayer{
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addr: addr,
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connCh: make(chan net.Conn),
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tlsWrap: tlsWrap,
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closeCh: make(chan struct{}),
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}
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return layer
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}
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// Handoff is used to hand off a connection to the
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// RaftLayer. This allows it to be Accept()'ed
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func (l *RaftLayer) Handoff(ctx context.Context, c net.Conn) error {
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select {
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case l.connCh <- c:
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return nil
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case <-l.closeCh:
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return fmt.Errorf("Raft RPC layer closed")
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case <-ctx.Done():
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return nil
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}
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}
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// Accept is used to return connection which are
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// dialed to be used with the Raft layer
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func (l *RaftLayer) Accept() (net.Conn, error) {
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select {
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case conn := <-l.connCh:
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return conn, nil
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case <-l.closeCh:
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return nil, fmt.Errorf("Raft RPC layer closed")
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}
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}
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// Close is used to stop listening for Raft connections
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func (l *RaftLayer) Close() error {
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l.closeLock.Lock()
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defer l.closeLock.Unlock()
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if !l.closed {
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l.closed = true
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close(l.closeCh)
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}
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return nil
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}
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// getTLSWrapper is used to retrieve the current TLS wrapper
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func (l *RaftLayer) getTLSWrapper() tlsutil.Wrapper {
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l.tlsWrapLock.RLock()
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defer l.tlsWrapLock.RUnlock()
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return l.tlsWrap
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}
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// ReloadTLS swaps the TLS wrapper. This is useful when upgrading or
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// downgrading TLS connections.
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func (l *RaftLayer) ReloadTLS(tlsWrap tlsutil.Wrapper) {
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l.tlsWrapLock.Lock()
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defer l.tlsWrapLock.Unlock()
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l.tlsWrap = tlsWrap
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}
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// Addr is used to return the address of the listener
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func (l *RaftLayer) Addr() net.Addr {
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return l.addr
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}
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// Dial is used to create a new outgoing connection
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func (l *RaftLayer) Dial(address raft.ServerAddress, timeout time.Duration) (net.Conn, error) {
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conn, err := net.DialTimeout("tcp", string(address), timeout)
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if err != nil {
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return nil, err
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}
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tlsWrapper := l.getTLSWrapper()
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// Check for tls mode
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if tlsWrapper != nil {
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// Switch the connection into TLS mode
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if _, err := conn.Write([]byte{byte(pool.RpcTLS)}); err != nil {
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conn.Close()
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return nil, err
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}
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// Wrap the connection in a TLS client
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conn, err = tlsWrapper(conn)
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if err != nil {
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return nil, err
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}
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}
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// Write the Raft byte to set the mode
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_, err = conn.Write([]byte{byte(pool.RpcRaft)})
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if err != nil {
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conn.Close()
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return nil, err
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}
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return conn, err
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}
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