open-nomad/api/fs.go
Mahmood Ali b77fd8654b cli: recover from client ACL lookup failures
This fixes a bug in the CLI handling of node lookup failures when
querying allocation and FS endpoints.

Allocation and FS endpoint are handled by the client; one can query the
relevant client directly, or query a server to have it forwarded
transparently to relevant client.  Querying the client directly is
benefecial to avoid loading servers with IO.

As an optimization, the CLI attempts to query the client directly, but
then falls back to using server forwarding path if it encounters network
or connection errors (e.g. clients are locked down or in a separate
inaccessible network).

Here, we fix a bug where if the CLI fails to find to lookup the client
details because it lacks ACL capability or other unexpected reasons, the
CLI will not go through fallback path.
2019-10-04 11:23:59 -04:00

384 lines
9.2 KiB
Go

package api
import (
"encoding/json"
"fmt"
"io"
"net"
"strconv"
"sync"
"time"
)
const (
// OriginStart and OriginEnd are the available parameters for the origin
// argument when streaming a file. They respectively offset from the start
// and end of a file.
OriginStart = "start"
OriginEnd = "end"
)
// AllocFileInfo holds information about a file inside the AllocDir
type AllocFileInfo struct {
Name string
IsDir bool
Size int64
FileMode string
ModTime time.Time
ContentType string
}
// StreamFrame is used to frame data of a file when streaming
type StreamFrame struct {
Offset int64 `json:",omitempty"`
Data []byte `json:",omitempty"`
File string `json:",omitempty"`
FileEvent string `json:",omitempty"`
}
// IsHeartbeat returns if the frame is a heartbeat frame
func (s *StreamFrame) IsHeartbeat() bool {
return len(s.Data) == 0 && s.FileEvent == "" && s.File == "" && s.Offset == 0
}
// AllocFS is used to introspect an allocation directory on a Nomad client
type AllocFS struct {
client *Client
}
// AllocFS returns an handle to the AllocFS endpoints
func (c *Client) AllocFS() *AllocFS {
return &AllocFS{client: c}
}
// List is used to list the files at a given path of an allocation directory
func (a *AllocFS) List(alloc *Allocation, path string, q *QueryOptions) ([]*AllocFileInfo, *QueryMeta, error) {
if q == nil {
q = &QueryOptions{}
}
if q.Params == nil {
q.Params = make(map[string]string)
}
q.Params["path"] = path
var resp []*AllocFileInfo
qm, err := a.client.query(fmt.Sprintf("/v1/client/fs/ls/%s", alloc.ID), &resp, q)
if err != nil {
return nil, nil, err
}
return resp, qm, nil
}
// Stat is used to stat a file at a given path of an allocation directory
func (a *AllocFS) Stat(alloc *Allocation, path string, q *QueryOptions) (*AllocFileInfo, *QueryMeta, error) {
if q == nil {
q = &QueryOptions{}
}
if q.Params == nil {
q.Params = make(map[string]string)
}
q.Params["path"] = path
var resp AllocFileInfo
qm, err := a.client.query(fmt.Sprintf("/v1/client/fs/stat/%s", alloc.ID), &resp, q)
if err != nil {
return nil, nil, err
}
return &resp, qm, nil
}
// ReadAt is used to read bytes at a given offset until limit at the given path
// in an allocation directory. If limit is <= 0, there is no limit.
func (a *AllocFS) ReadAt(alloc *Allocation, path string, offset int64, limit int64, q *QueryOptions) (io.ReadCloser, error) {
reqPath := fmt.Sprintf("/v1/client/fs/readat/%s", alloc.ID)
return queryClientNode(a.client, alloc, reqPath, q,
func(q *QueryOptions) {
q.Params["path"] = path
q.Params["offset"] = strconv.FormatInt(offset, 10)
q.Params["limit"] = strconv.FormatInt(limit, 10)
})
}
// Cat is used to read contents of a file at the given path in an allocation
// directory
func (a *AllocFS) Cat(alloc *Allocation, path string, q *QueryOptions) (io.ReadCloser, error) {
reqPath := fmt.Sprintf("/v1/client/fs/cat/%s", alloc.ID)
return queryClientNode(a.client, alloc, reqPath, q,
func(q *QueryOptions) {
q.Params["path"] = path
})
}
// Stream streams the content of a file blocking on EOF.
// The parameters are:
// * path: path to file to stream.
// * offset: The offset to start streaming data at.
// * origin: Either "start" or "end" and defines from where the offset is applied.
// * cancel: A channel that when closed, streaming will end.
//
// The return value is a channel that will emit StreamFrames as they are read.
func (a *AllocFS) Stream(alloc *Allocation, path, origin string, offset int64,
cancel <-chan struct{}, q *QueryOptions) (<-chan *StreamFrame, <-chan error) {
errCh := make(chan error, 1)
reqPath := fmt.Sprintf("/v1/client/fs/stream/%s", alloc.ID)
r, err := queryClientNode(a.client, alloc, reqPath, q,
func(q *QueryOptions) {
q.Params["path"] = path
q.Params["offset"] = strconv.FormatInt(offset, 10)
q.Params["origin"] = origin
})
if err != nil {
errCh <- err
return nil, errCh
}
// Create the output channel
frames := make(chan *StreamFrame, 10)
go func() {
// Close the body
defer r.Close()
// Create a decoder
dec := json.NewDecoder(r)
for {
// Check if we have been cancelled
select {
case <-cancel:
return
default:
}
// Decode the next frame
var frame StreamFrame
if err := dec.Decode(&frame); err != nil {
errCh <- err
close(frames)
return
}
// Discard heartbeat frames
if frame.IsHeartbeat() {
continue
}
frames <- &frame
}
}()
return frames, errCh
}
func queryClientNode(c *Client, alloc *Allocation, reqPath string, q *QueryOptions, customizeQ func(*QueryOptions)) (io.ReadCloser, error) {
nodeClient, _ := c.GetNodeClientWithTimeout(alloc.NodeID, ClientConnTimeout, q)
if q == nil {
q = &QueryOptions{}
}
if q.Params == nil {
q.Params = make(map[string]string)
}
if customizeQ != nil {
customizeQ(q)
}
var r io.ReadCloser
var err error
if nodeClient != nil {
r, err = nodeClient.rawQuery(reqPath, q)
if _, ok := err.(net.Error); err != nil && !ok {
// found a non networking error talking to client directly
return nil, err
}
}
// failed to query node, access through server directly
// or network error when talking to the client directly
if r == nil {
return c.rawQuery(reqPath, q)
}
return r, err
}
// Logs streams the content of a tasks logs blocking on EOF.
// The parameters are:
// * allocation: the allocation to stream from.
// * follow: Whether the logs should be followed.
// * task: the tasks name to stream logs for.
// * logType: Either "stdout" or "stderr"
// * origin: Either "start" or "end" and defines from where the offset is applied.
// * offset: The offset to start streaming data at.
// * cancel: A channel that when closed, streaming will end.
//
// The return value is a channel that will emit StreamFrames as they are read.
// The chan will be closed when follow=false and the end of the file is
// reached.
//
// Unexpected (non-EOF) errors will be sent on the error chan.
func (a *AllocFS) Logs(alloc *Allocation, follow bool, task, logType, origin string,
offset int64, cancel <-chan struct{}, q *QueryOptions) (<-chan *StreamFrame, <-chan error) {
errCh := make(chan error, 1)
reqPath := fmt.Sprintf("/v1/client/fs/logs/%s", alloc.ID)
r, err := queryClientNode(a.client, alloc, reqPath, q,
func(q *QueryOptions) {
q.Params["follow"] = strconv.FormatBool(follow)
q.Params["task"] = task
q.Params["type"] = logType
q.Params["origin"] = origin
q.Params["offset"] = strconv.FormatInt(offset, 10)
})
if err != nil {
errCh <- err
return nil, errCh
}
// Create the output channel
frames := make(chan *StreamFrame, 10)
go func() {
// Close the body
defer r.Close()
// Create a decoder
dec := json.NewDecoder(r)
for {
// Check if we have been cancelled
select {
case <-cancel:
return
default:
}
// Decode the next frame
var frame StreamFrame
if err := dec.Decode(&frame); err != nil {
if err == io.EOF || err == io.ErrClosedPipe {
close(frames)
} else {
errCh <- err
}
return
}
// Discard heartbeat frames
if frame.IsHeartbeat() {
continue
}
frames <- &frame
}
}()
return frames, errCh
}
// FrameReader is used to convert a stream of frames into a read closer.
type FrameReader struct {
frames <-chan *StreamFrame
errCh <-chan error
cancelCh chan struct{}
closedLock sync.Mutex
closed bool
unblockTime time.Duration
frame *StreamFrame
frameOffset int
byteOffset int
}
// NewFrameReader takes a channel of frames and returns a FrameReader which
// implements io.ReadCloser
func NewFrameReader(frames <-chan *StreamFrame, errCh <-chan error, cancelCh chan struct{}) *FrameReader {
return &FrameReader{
frames: frames,
errCh: errCh,
cancelCh: cancelCh,
}
}
// SetUnblockTime sets the time to unblock and return zero bytes read. If the
// duration is unset or is zero or less, the read will block until data is read.
func (f *FrameReader) SetUnblockTime(d time.Duration) {
f.unblockTime = d
}
// Offset returns the offset into the stream.
func (f *FrameReader) Offset() int {
return f.byteOffset
}
// Read reads the data of the incoming frames into the bytes buffer. Returns EOF
// when there are no more frames.
func (f *FrameReader) Read(p []byte) (n int, err error) {
f.closedLock.Lock()
closed := f.closed
f.closedLock.Unlock()
if closed {
return 0, io.EOF
}
if f.frame == nil {
var unblock <-chan time.Time
if f.unblockTime.Nanoseconds() > 0 {
unblock = time.After(f.unblockTime)
}
select {
case frame, ok := <-f.frames:
if !ok {
return 0, io.EOF
}
f.frame = frame
// Store the total offset into the file
f.byteOffset = int(f.frame.Offset)
case <-unblock:
return 0, nil
case err := <-f.errCh:
return 0, err
case <-f.cancelCh:
return 0, io.EOF
}
}
// Copy the data out of the frame and update our offset
n = copy(p, f.frame.Data[f.frameOffset:])
f.frameOffset += n
// Clear the frame and its offset once we have read everything
if len(f.frame.Data) == f.frameOffset {
f.frame = nil
f.frameOffset = 0
}
return n, nil
}
// Close cancels the stream of frames
func (f *FrameReader) Close() error {
f.closedLock.Lock()
defer f.closedLock.Unlock()
if f.closed {
return nil
}
close(f.cancelCh)
f.closed = true
return nil
}