+/* Provides low-level Get/Put primitives for accessing Arvados Keep blocks. */
package keepclient
import (
+ "arvados.org/streamer"
"crypto/md5"
"crypto/tls"
- "encoding/json"
"errors"
"fmt"
"io"
"io/ioutil"
- "log"
"net/http"
"os"
"sort"
- "strconv"
+ "sync"
+ "sync/atomic"
+ "unsafe"
)
// A Keep "block" is 64MB.
var BlockNotFound = errors.New("Block not found")
var InsufficientReplicasError = errors.New("Could not write sufficient replicas")
+var OversizeBlockError = errors.New("Block too big")
+var MissingArvadosApiHost = errors.New("Missing required environment variable ARVADOS_API_HOST")
+var MissingArvadosApiToken = errors.New("Missing required environment variable ARVADOS_API_TOKEN")
+
+const X_Keep_Desired_Replicas = "X-Keep-Desired-Replicas"
+const X_Keep_Replicas_Stored = "X-Keep-Replicas-Stored"
+// Information about Arvados and Keep servers.
type KeepClient struct {
ApiServer string
ApiToken string
ApiInsecure bool
- Service_roots []string
Want_replicas int
Client *http.Client
+ Using_proxy bool
+ External bool
+ service_roots *[]string
+ lock sync.Mutex
}
-type KeepDisk struct {
- Hostname string `json:"service_host"`
- Port int `json:"service_port"`
- SSL bool `json:"service_ssl_flag"`
-}
-
+// Create a new KeepClient, initialized with standard Arvados environment
+// variables ARVADOS_API_HOST, ARVADOS_API_TOKEN, and (optionally)
+// ARVADOS_API_HOST_INSECURE. This will contact the API server to discover
+// Keep servers.
func MakeKeepClient() (kc KeepClient, err error) {
- tr := &http.Transport{
- TLSClientConfig: &tls.Config{InsecureSkipVerify: kc.ApiInsecure},
- }
+ insecure := (os.Getenv("ARVADOS_API_HOST_INSECURE") == "true")
+ external := (os.Getenv("ARVADOS_EXTERNAL_CLIENT") == "true")
kc = KeepClient{
ApiServer: os.Getenv("ARVADOS_API_HOST"),
ApiToken: os.Getenv("ARVADOS_API_TOKEN"),
- ApiInsecure: (os.Getenv("ARVADOS_API_HOST_INSECURE") != ""),
+ ApiInsecure: insecure,
Want_replicas: 2,
- Client: &http.Client{Transport: tr}}
-
- err = (&kc).DiscoverKeepServers()
-
- return kc, err
-}
-
-func (this *KeepClient) DiscoverKeepServers() error {
- // Construct request of keep disk list
- var req *http.Request
- var err error
- if req, err = http.NewRequest("GET", fmt.Sprintf("https://%s/arvados/v1/keep_disks", this.ApiServer), nil); err != nil {
- return err
- }
-
- // Add api token header
- req.Header.Add("Authorization", fmt.Sprintf("OAuth2 %s", this.ApiToken))
-
- // Make the request
- var resp *http.Response
- if resp, err = this.Client.Do(req); err != nil {
- return err
- }
-
- type SvcList struct {
- Items []KeepDisk `json:"items"`
- }
-
- // Decode json reply
- dec := json.NewDecoder(resp.Body)
- var m SvcList
- if err := dec.Decode(&m); err != nil {
- return err
- }
-
- listed := make(map[string]bool)
- this.Service_roots = make([]string, 0, len(m.Items))
-
- for _, element := range m.Items {
- n := ""
- if element.SSL {
- n = "s"
- }
-
- // Construct server URL
- url := fmt.Sprintf("http%s://%s:%d", n, element.Hostname, element.Port)
-
- // Skip duplicates
- if !listed[url] {
- listed[url] = true
- this.Service_roots = append(this.Service_roots, url)
- }
- }
-
- // Must be sorted for ShuffledServiceRoots() to produce consistent
- // results.
- sort.Strings(this.Service_roots)
-
- return nil
-}
-
-func (this KeepClient) ShuffledServiceRoots(hash string) (pseq []string) {
- // Build an ordering with which to query the Keep servers based on the
- // contents of the hash. "hash" is a hex-encoded number at least 8
- // digits (32 bits) long
-
- // seed used to calculate the next keep server from 'pool' to be added
- // to 'pseq'
- seed := hash
-
- // Keep servers still to be added to the ordering
- pool := make([]string, len(this.Service_roots))
- copy(pool, this.Service_roots)
-
- // output probe sequence
- pseq = make([]string, 0, len(this.Service_roots))
-
- // iterate while there are servers left to be assigned
- for len(pool) > 0 {
-
- if len(seed) < 8 {
- // ran out of digits in the seed
- if len(pseq) < (len(hash) / 4) {
- // the number of servers added to the probe
- // sequence is less than the number of 4-digit
- // slices in 'hash' so refill the seed with the
- // last 4 digits.
- seed = hash[len(hash)-4:]
- }
- seed += hash
- }
-
- // Take the next 8 digits (32 bytes) and interpret as an integer,
- // then modulus with the size of the remaining pool to get the next
- // selected server.
- probe, _ := strconv.ParseUint(seed[0:8], 16, 32)
- probe %= uint64(len(pool))
-
- // Append the selected server to the probe sequence and remove it
- // from the pool.
- pseq = append(pseq, pool[probe])
- pool = append(pool[:probe], pool[probe+1:]...)
-
- // Remove the digits just used from the seed
- seed = seed[8:]
- }
- return pseq
-}
-
-type ReaderSlice struct {
- slice []byte
- reader_error error
-}
-
-// Read repeatedly from the reader into the specified buffer, and report each
-// read to channel 'c'. Completes when Reader 'r' reports on the error channel
-// and closes channel 'c'.
-func ReadIntoBuffer(buffer []byte, r io.Reader, slices chan<- ReaderSlice) {
- defer close(slices)
-
- // Initially use entire buffer as scratch space
- ptr := buffer[:]
- for {
- var n int
- var err error
- if len(ptr) > 0 {
- // Read into the scratch space
- n, err = r.Read(ptr)
- } else {
- // Ran out of scratch space, try reading one more byte
- var b [1]byte
- n, err = r.Read(b[:])
-
- if n > 0 {
- // Reader has more data but we have nowhere to
- // put it, so we're stuffed
- slices <- ReaderSlice{nil, io.ErrShortBuffer}
- } else {
- // Return some other error (hopefully EOF)
- slices <- ReaderSlice{nil, err}
- }
- return
- }
-
- // End on error (includes EOF)
- if err != nil {
- slices <- ReaderSlice{nil, err}
- return
- }
-
- if n > 0 {
- // Make a slice with the contents of the read
- slices <- ReaderSlice{ptr[:n], nil}
-
- // Adjust the scratch space slice
- ptr = ptr[n:]
- }
- }
-}
-
-// A read request to the Transfer() function
-type ReadRequest struct {
- offset int
- maxsize int
- result chan<- ReadResult
-}
-
-// A read result from the Transfer() function
-type ReadResult struct {
- slice []byte
- err error
-}
-
-// Reads from the buffer managed by the Transfer()
-type BufferReader struct {
- offset *int
- requests chan<- ReadRequest
- responses chan ReadResult
-}
-
-func MakeBufferReader(requests chan<- ReadRequest) BufferReader {
- return BufferReader{new(int), requests, make(chan ReadResult)}
-}
+ Client: &http.Client{Transport: &http.Transport{
+ TLSClientConfig: &tls.Config{InsecureSkipVerify: insecure}}},
+ Using_proxy: false,
+ External: external}
-// Reads from the buffer managed by the Transfer()
-func (this BufferReader) Read(p []byte) (n int, err error) {
- this.requests <- ReadRequest{*this.offset, len(p), this.responses}
- rr, valid := <-this.responses
- if valid {
- *this.offset += len(rr.slice)
- return copy(p, rr.slice), rr.err
- } else {
- return 0, io.ErrUnexpectedEOF
- }
-}
-
-func (this BufferReader) WriteTo(dest io.Writer) (written int64, err error) {
- // Record starting offset in order to correctly report the number of bytes sent
- starting_offset := *this.offset
- for {
- this.requests <- ReadRequest{*this.offset, 32 * 1024, this.responses}
- rr, valid := <-this.responses
- if valid {
- log.Printf("WriteTo slice %v %d %v", *this.offset, len(rr.slice), rr.err)
- *this.offset += len(rr.slice)
- if rr.err != nil {
- if rr.err == io.EOF {
- // EOF is not an error.
- return int64(*this.offset - starting_offset), nil
- } else {
- return int64(*this.offset - starting_offset), rr.err
- }
- } else {
- dest.Write(rr.slice)
- }
- } else {
- return int64(*this.offset), io.ErrUnexpectedEOF
- }
- }
-}
-
-// Close the responses channel
-func (this BufferReader) Close() error {
- close(this.responses)
- return nil
-}
-
-// Handle a read request. Returns true if a response was sent, and false if
-// the request should be queued.
-func HandleReadRequest(req ReadRequest, body []byte, complete bool) bool {
- log.Printf("HandleReadRequest %d %d %d", req.offset, req.maxsize, len(body))
- if req.offset < len(body) {
- var end int
- if req.offset+req.maxsize < len(body) {
- end = req.offset + req.maxsize
- } else {
- end = len(body)
- }
- req.result <- ReadResult{body[req.offset:end], nil}
- return true
- } else if complete && req.offset >= len(body) {
- req.result <- ReadResult{nil, io.EOF}
- return true
- } else {
- return false
- }
-}
-
-// If 'source_reader' is not nil, reads data from 'source_reader' and stores it
-// in the provided buffer. Otherwise, use the contents of 'buffer' as is.
-// Accepts read requests on the buffer on the 'requests' channel. Completes
-// when 'requests' channel is closed.
-func Transfer(source_buffer []byte, source_reader io.Reader, requests <-chan ReadRequest, reader_error chan error) {
- // currently buffered data
- var body []byte
-
- // for receiving slices from ReadIntoBuffer
- var slices chan ReaderSlice = nil
-
- // indicates whether the buffered data is complete
- var complete bool = false
-
- if source_reader != nil {
- // 'body' is the buffer slice representing the body content read so far
- body = source_buffer[:0]
-
- // used to communicate slices of the buffer as they are
- // ReadIntoBuffer will close 'slices' when it is done with it
- slices = make(chan ReaderSlice)
-
- // Spin it off
- go ReadIntoBuffer(source_buffer, source_reader, slices)
- } else {
- // use the whole buffer
- body = source_buffer[:]
-
- // buffer is complete
- complete = true
- }
-
- pending_requests := make([]ReadRequest, 0)
-
- for {
- select {
- case req, valid := <-requests:
- // Handle a buffer read request
- if valid {
- if !HandleReadRequest(req, body, complete) {
- pending_requests = append(pending_requests, req)
- }
- } else {
- // closed 'requests' channel indicates we're done
- return
- }
-
- case bk, valid := <-slices:
- // Got a new slice from the reader
- if valid {
- if bk.reader_error != nil {
- reader_error <- bk.reader_error
- if bk.reader_error == io.EOF {
- // EOF indicates the reader is done
- // sending, so our buffer is complete.
- complete = true
- } else {
- // some other reader error
- return
- }
- }
-
- if bk.slice != nil {
- // adjust body bounds now that another slice has been read
- body = source_buffer[0 : len(body)+len(bk.slice)]
- }
-
- // handle pending reads
- n := 0
- for n < len(pending_requests) {
- if HandleReadRequest(pending_requests[n], body, complete) {
-
- // move the element from the
- // back of the slice to
- // position 'n', then shorten
- // the slice by one element
- pending_requests[n] = pending_requests[len(pending_requests)-1]
- pending_requests = pending_requests[0 : len(pending_requests)-1]
- } else {
-
- // Request wasn't handled, so keep it in the request slice
- n += 1
- }
- }
- } else {
- if complete {
- // no more reads
- slices = nil
- } else {
- // reader channel closed without signaling EOF
- reader_error <- io.ErrUnexpectedEOF
- return
- }
- }
- }
- }
-}
-
-type UploadStatus struct {
- Err error
- Url string
- StatusCode int
-}
-
-func (this KeepClient) uploadToKeepServer(host string, hash string, body io.ReadCloser,
- upload_status chan<- UploadStatus, expectedLength int64) {
-
- log.Printf("Uploading to %s", host)
-
- var req *http.Request
- var err error
- var url = fmt.Sprintf("%s/%s", host, hash)
- if req, err = http.NewRequest("PUT", url, nil); err != nil {
- upload_status <- UploadStatus{err, url, 0}
- return
+ if os.Getenv("ARVADOS_API_HOST") == "" {
+ return kc, MissingArvadosApiHost
}
-
- if expectedLength > 0 {
- req.ContentLength = expectedLength
+ if os.Getenv("ARVADOS_API_TOKEN") == "" {
+ return kc, MissingArvadosApiToken
}
- req.Header.Add("Authorization", fmt.Sprintf("OAuth2 %s", this.ApiToken))
- req.Header.Add("Content-Type", "application/octet-stream")
- req.Body = body
-
- var resp *http.Response
- if resp, err = this.Client.Do(req); err != nil {
- upload_status <- UploadStatus{err, url, 0}
- return
- }
-
- if resp.StatusCode == http.StatusOK {
- upload_status <- UploadStatus{nil, url, resp.StatusCode}
- } else {
- upload_status <- UploadStatus{errors.New(resp.Status), url, resp.StatusCode}
- }
-}
-
-func (this KeepClient) putReplicas(
- hash string,
- requests chan ReadRequest,
- reader_status chan error,
- expectedLength int64) (replicas int, err error) {
-
- // Calculate the ordering for uploading to servers
- sv := this.ShuffledServiceRoots(hash)
-
- // The next server to try contacting
- next_server := 0
-
- // The number of active writers
- active := 0
-
- // Used to communicate status from the upload goroutines
- upload_status := make(chan UploadStatus)
- defer close(upload_status)
-
- // Desired number of replicas
- remaining_replicas := this.Want_replicas
-
- for remaining_replicas > 0 {
- for active < remaining_replicas {
- // Start some upload requests
- if next_server < len(sv) {
- go this.uploadToKeepServer(sv[next_server], hash, MakeBufferReader(requests), upload_status, expectedLength)
- next_server += 1
- active += 1
- } else {
- return (this.Want_replicas - remaining_replicas), InsufficientReplicasError
- }
- }
-
- // Now wait for something to happen.
- select {
- case status := <-reader_status:
- if status == io.EOF {
- // good news!
- } else {
- // bad news
- return (this.Want_replicas - remaining_replicas), status
- }
- case status := <-upload_status:
- if status.StatusCode == 200 {
- // good news!
- remaining_replicas -= 1
- } else {
- // writing to keep server failed for some reason
- log.Printf("Keep server put to %v failed with '%v'",
- status.Url, status.Err)
- }
- active -= 1
- log.Printf("Upload status %v %v %v", status.StatusCode, remaining_replicas, active)
- }
- }
+ err = (&kc).DiscoverKeepServers()
- return (this.Want_replicas - remaining_replicas), nil
+ return kc, err
}
-var OversizeBlockError = errors.New("Block too big")
-
+// Put a block given the block hash, a reader with the block data, and the
+// expected length of that data. The desired number of replicas is given in
+// KeepClient.Want_replicas. Returns the number of replicas that were written
+// and if there was an error. Note this will return InsufficientReplias
+// whenever 0 <= replicas < this.Wants_replicas.
func (this KeepClient) PutHR(hash string, r io.Reader, expectedLength int64) (replicas int, err error) {
// Buffer for reads from 'r'
- var buffer []byte
+ var bufsize int
if expectedLength > 0 {
if expectedLength > BLOCKSIZE {
return 0, OversizeBlockError
}
- buffer = make([]byte, expectedLength)
+ bufsize = int(expectedLength)
} else {
- buffer = make([]byte, BLOCKSIZE)
+ bufsize = BLOCKSIZE
}
- // Read requests on Transfer() buffer
- requests := make(chan ReadRequest)
- defer close(requests)
-
- // Reporting reader error states
- reader_status := make(chan error)
- defer close(reader_status)
-
- // Start the transfer goroutine
- go Transfer(buffer, r, requests, reader_status)
+ t := streamer.AsyncStreamFromReader(bufsize, HashCheckingReader{r, md5.New(), hash})
+ defer t.Close()
- return this.putReplicas(hash, requests, reader_status, expectedLength)
+ return this.putReplicas(hash, t, expectedLength)
}
-func (this KeepClient) PutHB(hash string, buffer []byte) (replicas int, err error) {
- // Read requests on Transfer() buffer
- requests := make(chan ReadRequest)
- defer close(requests)
+// Put a block given the block hash and a byte buffer. The desired number of
+// replicas is given in KeepClient.Want_replicas. Returns the number of
+// replicas that were written and if there was an error. Note this will return
+// InsufficientReplias whenever 0 <= replicas < this.Wants_replicas.
+func (this KeepClient) PutHB(hash string, buf []byte) (replicas int, err error) {
+ t := streamer.AsyncStreamFromSlice(buf)
+ defer t.Close()
- // Start the transfer goroutine
- go Transfer(buffer, nil, requests, nil)
-
- return this.putReplicas(hash, requests, nil, int64(len(buffer)))
+ return this.putReplicas(hash, t, int64(len(buf)))
}
+// Put a block given a buffer. The hash will be computed. The desired number
+// of replicas is given in KeepClient.Want_replicas. Returns the number of
+// replicas that were written and if there was an error. Note this will return
+// InsufficientReplias whenever 0 <= replicas < this.Wants_replicas.
func (this KeepClient) PutB(buffer []byte) (hash string, replicas int, err error) {
hash = fmt.Sprintf("%x", md5.Sum(buffer))
replicas, err = this.PutHB(hash, buffer)
return hash, replicas, err
}
+// Put a block, given a Reader. This will read the entire reader into a buffer
+// to computed the hash. The desired number of replicas is given in
+// KeepClient.Want_replicas. Returns the number of replicas that were written
+// and if there was an error. Note this will return InsufficientReplias
+// whenever 0 <= replicas < this.Wants_replicas. Also nhote that if the block
+// hash and data size are available, PutHR() is more efficient.
func (this KeepClient) PutR(r io.Reader) (hash string, replicas int, err error) {
if buffer, err := ioutil.ReadAll(r); err != nil {
return "", 0, err
}
}
+// Get a block given a hash. Return a reader, the expected data length, the
+// URL the block was fetched from, and if there was an error. If the block
+// checksum does not match, the final Read() on the reader returned by this
+// method will return a BadChecksum error instead of EOF.
func (this KeepClient) Get(hash string) (reader io.ReadCloser,
contentLength int64, url string, err error) {
return this.AuthorizedGet(hash, "", "")
}
+// Get a block given a hash, with additional authorization provided by
+// signature and timestamp. Return a reader, the expected data length, the URL
+// the block was fetched from, and if there was an error. If the block
+// checksum does not match, the final Read() on the reader returned by this
+// method will return a BadChecksum error instead of EOF.
func (this KeepClient) AuthorizedGet(hash string,
signature string,
timestamp string) (reader io.ReadCloser,
contentLength int64, url string, err error) {
// Calculate the ordering for asking servers
- sv := this.ShuffledServiceRoots(hash)
+ sv := this.shuffledServiceRoots(hash)
for _, host := range sv {
var req *http.Request
}
if resp.StatusCode == http.StatusOK {
- return resp.Body, resp.ContentLength, url, nil
+ return HashCheckingReader{resp.Body, md5.New(), hash}, resp.ContentLength, url, nil
}
}
return nil, 0, "", BlockNotFound
}
+// Determine if a block with the given hash is available and readable, but does
+// not return the block contents.
func (this KeepClient) Ask(hash string) (contentLength int64, url string, err error) {
return this.AuthorizedAsk(hash, "", "")
}
+// Determine if a block with the given hash is available and readable with the
+// given signature and timestamp, but does not return the block contents.
func (this KeepClient) AuthorizedAsk(hash string, signature string,
timestamp string) (contentLength int64, url string, err error) {
// Calculate the ordering for asking servers
- sv := this.ShuffledServiceRoots(hash)
+ sv := this.shuffledServiceRoots(hash)
for _, host := range sv {
var req *http.Request
return 0, "", BlockNotFound
}
+
+// Atomically read the service_roots field.
+func (this *KeepClient) ServiceRoots() []string {
+ r := (*[]string)(atomic.LoadPointer((*unsafe.Pointer)(unsafe.Pointer(&this.service_roots))))
+ return *r
+}
+
+// Atomically update the service_roots field. Enables you to update
+// service_roots without disrupting any GET or PUT operations that might
+// already be in progress.
+func (this *KeepClient) SetServiceRoots(svc []string) {
+ // Must be sorted for ShuffledServiceRoots() to produce consistent
+ // results.
+ roots := make([]string, len(svc))
+ copy(roots, svc)
+ sort.Strings(roots)
+ atomic.StorePointer((*unsafe.Pointer)(unsafe.Pointer(&this.service_roots)),
+ unsafe.Pointer(&roots))
+}
projects / arvados.git / blobdiff