package keepclient
import (
+ "bufio"
"bytes"
"context"
"crypto/md5"
"io/ioutil"
"net"
"net/http"
+ "os"
+ "path/filepath"
"regexp"
"strconv"
"strings"
DefaultProxyConnectTimeout = 30 * time.Second
DefaultProxyTLSHandshakeTimeout = 10 * time.Second
DefaultProxyKeepAlive = 120 * time.Second
+
+ DefaultRetryDelay = 2 * time.Second // see KeepClient.RetryDelay
+ MinimumRetryDelay = time.Millisecond
+
+ rootCacheDir = "/var/cache/arvados/keep"
+ userCacheDir = ".cache/arvados/keep" // relative to HOME
)
// Error interface with an error and boolean indicating whether the error is temporary
multipleResponseError
}
+func (*ErrNotFound) HTTPStatus() int { return http.StatusNotFound }
+
type InsufficientReplicasError struct{ error }
type OversizeBlockError struct{ error }
Do(*http.Request) (*http.Response, error)
}
+const DiskCacheDisabled = arvados.ByteSizeOrPercent(1)
+
// KeepClient holds information about Arvados and Keep servers.
type KeepClient struct {
- Arvados *arvadosclient.ArvadosClient
- Want_replicas int
- localRoots map[string]string
- writableLocalRoots map[string]string
- gatewayRoots map[string]string
- lock sync.RWMutex
- HTTPClient HTTPClient
- Retries int
- BlockCache *BlockCache
+ Arvados *arvadosclient.ArvadosClient
+ Want_replicas int
+ localRoots map[string]string
+ writableLocalRoots map[string]string
+ gatewayRoots map[string]string
+ lock sync.RWMutex
+ HTTPClient HTTPClient
+
+ // Number of times to automatically retry a read/write
+ // operation after a transient failure.
+ Retries int
+
+ // Initial maximum delay for automatic retry. If zero,
+ // DefaultRetryDelay is used. The delay after attempt N
+ // (0-based) will be a random duration between
+ // MinimumRetryDelay and RetryDelay * 2^N, not to exceed a cap
+ // of RetryDelay * 10.
+ RetryDelay time.Duration
+
RequestID string
StorageClasses []string
- DefaultStorageClasses []string // Set by cluster's exported config
+ DefaultStorageClasses []string // Set by cluster's exported config
+ DiskCacheSize arvados.ByteSizeOrPercent // See also DiskCacheDisabled
// set to 1 if all writable services are of disk type, otherwise 0
replicasPerService int
// Disable automatic discovery of keep services
disableDiscovery bool
+
+ gatewayStack arvados.KeepGateway
}
func (kc *KeepClient) Clone() *KeepClient {
gatewayRoots: kc.gatewayRoots,
HTTPClient: kc.HTTPClient,
Retries: kc.Retries,
- BlockCache: kc.BlockCache,
+ RetryDelay: kc.RetryDelay,
RequestID: kc.RequestID,
StorageClasses: kc.StorageClasses,
DefaultStorageClasses: kc.DefaultStorageClasses,
+ DiskCacheSize: kc.DiskCacheSize,
replicasPerService: kc.replicasPerService,
foundNonDiskSvc: kc.foundNonDiskSvc,
disableDiscovery: kc.disableDiscovery,
var errs []string
+ delay := delayCalculator{InitialMaxDelay: kc.RetryDelay}
triesRemaining := 1 + kc.Retries
serversToTry := kc.getSortedRoots(locator)
return nil, expectLength, url, resp.Header, nil
}
serversToTry = retryList
+ if len(serversToTry) > 0 && triesRemaining > 0 {
+ time.Sleep(delay.Next())
+ }
}
DebugPrintf("DEBUG: %s %s failed: %v", method, locator, errs)
return nil, 0, "", nil, err
}
+// attempt to create dir/subdir/ and its parents, up to but not
+// including dir itself, using mode 0700.
+func makedirs(dir, subdir string) {
+ for _, part := range strings.Split(subdir, string(os.PathSeparator)) {
+ dir = filepath.Join(dir, part)
+ os.Mkdir(dir, 0700)
+ }
+}
+
+// upstreamGateway creates/returns the KeepGateway stack used to read
+// and write data: a disk-backed cache on top of an http backend.
+func (kc *KeepClient) upstreamGateway() arvados.KeepGateway {
+ kc.lock.Lock()
+ defer kc.lock.Unlock()
+ if kc.gatewayStack != nil {
+ return kc.gatewayStack
+ }
+ var cachedir string
+ if os.Geteuid() == 0 {
+ cachedir = rootCacheDir
+ makedirs("/", cachedir)
+ } else {
+ home := "/" + os.Getenv("HOME")
+ makedirs(home, userCacheDir)
+ cachedir = filepath.Join(home, userCacheDir)
+ }
+ backend := &keepViaHTTP{kc}
+ if kc.DiskCacheSize == DiskCacheDisabled {
+ kc.gatewayStack = backend
+ } else {
+ kc.gatewayStack = &arvados.DiskCache{
+ Dir: cachedir,
+ MaxSize: kc.DiskCacheSize,
+ KeepGateway: backend,
+ }
+ }
+ return kc.gatewayStack
+}
+
// LocalLocator returns a locator equivalent to the one supplied, but
// with a valid signature from the local cluster. If the given locator
// already has a local signature, it is returned unchanged.
func (kc *KeepClient) LocalLocator(locator string) (string, error) {
- if !strings.Contains(locator, "+R") {
- // Either it has +A, or it's unsigned and we assume
- // it's a local locator on a site with signatures
- // disabled.
- return locator, nil
- }
- sighdr := fmt.Sprintf("local, time=%s", time.Now().UTC().Format(time.RFC3339))
- _, _, url, hdr, err := kc.getOrHead("HEAD", locator, http.Header{"X-Keep-Signature": []string{sighdr}})
- if err != nil {
- return "", err
- }
- loc := hdr.Get("X-Keep-Locator")
- if loc == "" {
- return "", fmt.Errorf("missing X-Keep-Locator header in HEAD response from %s", url)
- }
- return loc, nil
+ return kc.upstreamGateway().LocalLocator(locator)
}
-// Get retrieves a block, given a locator. Returns a reader, the
-// expected data length, the URL the block is being fetched from, and
-// an error.
+// Get retrieves the specified block from the local cache or a backend
+// server. Returns a reader, the expected data length (or -1 if not
+// known), and an error.
+//
+// The third return value (formerly a source URL in previous versions)
+// is an empty string.
//
// 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.
+//
+// New code should use BlockRead and/or ReadAt instead of Get.
func (kc *KeepClient) Get(locator string) (io.ReadCloser, int64, string, error) {
- rdr, size, url, _, err := kc.getOrHead("GET", locator, nil)
- return rdr, size, url, err
+ loc, err := MakeLocator(locator)
+ if err != nil {
+ return nil, 0, "", err
+ }
+ pr, pw := io.Pipe()
+ go func() {
+ n, err := kc.BlockRead(context.Background(), arvados.BlockReadOptions{
+ Locator: locator,
+ WriteTo: pw,
+ })
+ if err != nil {
+ pw.CloseWithError(err)
+ } else if loc.Size >= 0 && n != loc.Size {
+ pw.CloseWithError(fmt.Errorf("expected block size %d but read %d bytes", loc.Size, n))
+ } else {
+ pw.Close()
+ }
+ }()
+ // Wait for the first byte to arrive, so that, if there's an
+ // error before we receive any data, we can return the error
+ // directly, instead of indirectly via a reader that returns
+ // an error.
+ bufr := bufio.NewReader(pr)
+ _, err = bufr.Peek(1)
+ if err != nil && err != io.EOF {
+ pr.CloseWithError(err)
+ return nil, 0, "", err
+ }
+ if err == io.EOF && (loc.Size == 0 || loc.Hash == "d41d8cd98f00b204e9800998ecf8427e") {
+ // In the special case of the zero-length block, EOF
+ // error from Peek() is normal.
+ return pr, 0, "", nil
+ }
+ return struct {
+ io.Reader
+ io.Closer
+ }{
+ Reader: bufr,
+ Closer: pr,
+ }, int64(loc.Size), "", err
+}
+
+// BlockRead retrieves a block from the cache if it's present, otherwise
+// from the network.
+func (kc *KeepClient) BlockRead(ctx context.Context, opts arvados.BlockReadOptions) (int, error) {
+ return kc.upstreamGateway().BlockRead(ctx, opts)
}
// ReadAt retrieves a portion of block from the cache if it's
// present, otherwise from the network.
func (kc *KeepClient) ReadAt(locator string, p []byte, off int) (int, error) {
- return kc.cache().ReadAt(kc, locator, p, off)
+ return kc.upstreamGateway().ReadAt(locator, p, off)
+}
+
+// BlockWrite writes a full block to upstream servers and saves a copy
+// in the local cache.
+func (kc *KeepClient) BlockWrite(ctx context.Context, req arvados.BlockWriteOptions) (arvados.BlockWriteResponse, error) {
+ return kc.upstreamGateway().BlockWrite(ctx, req)
}
// Ask verifies that a block with the given hash is available and
return found
}
-func (kc *KeepClient) cache() *BlockCache {
- if kc.BlockCache != nil {
- return kc.BlockCache
- }
- return DefaultBlockCache
-}
-
-func (kc *KeepClient) ClearBlockCache() {
- kc.cache().Clear()
-}
-
func (kc *KeepClient) SetStorageClasses(sc []string) {
// make a copy so the caller can't mess with it.
kc.StorageClasses = append([]string{}, sc...)