debug(core, datastore, daemon) wrap errors

@jbenet @whyrusleeping @mappum

very helpful for tracking down errors. the stack traces are only
shown when debug mode is visible. They function best when caught at the
source.

I propose we use this errors package as a drop-in replacement for
fmt.Errorf and errors.New in all of our code, and use errors.Wrap for
external errors as they emerge from others' libraries.

License: MIT
Signed-off-by: Brian Tiger Chow <brian@perfmode.com>
Signed-off-by: Brian Tiger Chow <brian.holderchow@gmail.com>

cmd/ipfs2/daemon.go

@@ -6,6 +6,7 @@ import (
 
 	ma "github.com/jbenet/go-ipfs/Godeps/_workspace/src/github.com/jbenet/go-multiaddr"
 	manet "github.com/jbenet/go-ipfs/Godeps/_workspace/src/github.com/jbenet/go-multiaddr/net"
+	errors "github.com/jbenet/go-ipfs/util/errors"
 
 	manners "github.com/jbenet/go-ipfs/Godeps/_workspace/src/github.com/braintree/manners"
 	cmds "github.com/jbenet/go-ipfs/commands"
@@ -35,7 +36,7 @@ the daemon.
 func daemonFunc(req cmds.Request) (interface{}, error) {
 	lock, err := daemon.Lock(req.Context().ConfigRoot)
 	if err != nil {
-		return nil, fmt.Errorf("Couldn't obtain lock. Is another daemon already running?")
+		return nil, errors.Errorf("Couldn't obtain lock. Is another daemon already running?")
 	}
 	defer lock.Close()
 

core/core.go

@@ -2,7 +2,6 @@ package core
 
 import (
 	"encoding/base64"
-	"errors"
 	"fmt"
 
 	context "github.com/jbenet/go-ipfs/Godeps/_workspace/src/code.google.com/p/go.net/context"
@@ -15,6 +14,7 @@ import (
 	exchange "github.com/jbenet/go-ipfs/exchange"
 	bitswap "github.com/jbenet/go-ipfs/exchange/bitswap"
 	bsnet "github.com/jbenet/go-ipfs/exchange/bitswap/network"
+	mount "github.com/jbenet/go-ipfs/fuse/mount"
 	merkledag "github.com/jbenet/go-ipfs/merkledag"
 	namesys "github.com/jbenet/go-ipfs/namesys"
 	inet "github.com/jbenet/go-ipfs/net"
@@ -26,8 +26,8 @@ import (
 	routing "github.com/jbenet/go-ipfs/routing"
 	dht "github.com/jbenet/go-ipfs/routing/dht"
 	u "github.com/jbenet/go-ipfs/util"
-	mount "github.com/jbenet/go-ipfs/fuse/mount"
 	ctxc "github.com/jbenet/go-ipfs/util/ctxcloser"
+	"github.com/jbenet/go-ipfs/util/errors"
 )
 
 const IpnsValidatorTag = "ipns"
@@ -102,7 +102,7 @@ func NewIpfsNode(cfg *config.Config, online bool) (n *IpfsNode, err error) {
 	}()
 
 	if cfg == nil {
-		return nil, fmt.Errorf("configuration required")
+		return nil, errors.Errorf("configuration required")
 	}
 
 	// derive this from a higher context.
@@ -115,14 +115,14 @@ func NewIpfsNode(cfg *config.Config, online bool) (n *IpfsNode, err error) {
 
 	// setup datastore.
 	if n.Datastore, err = makeDatastore(cfg.Datastore); err != nil {
-		return nil, err
+		return nil, errors.Wrap(err)
 	}
 
 	// setup peerstore + local peer identity
 	n.Peerstore = peer.NewPeerstore()
 	n.Identity, err = initIdentity(&n.Config.Identity, n.Peerstore, online)
 	if err != nil {
-		return nil, err
+		return nil, errors.Wrap(err)
 	}
 
 	// setup online services
@@ -142,12 +142,12 @@ func NewIpfsNode(cfg *config.Config, online bool) (n *IpfsNode, err error) {
 		// setup the network
 		listenAddrs, err := listenAddresses(cfg)
 		if err != nil {
-			return nil, err
+			return nil, errors.Wrap(err)
 		}
 
 		n.Network, err = inet.NewIpfsNetwork(ctx, listenAddrs, n.Identity, n.Peerstore, muxMap)
 		if err != nil {
-			return nil, err
+			return nil, errors.Wrap(err)
 		}
 		n.AddCloserChild(n.Network)
 
@@ -176,7 +176,7 @@ func NewIpfsNode(cfg *config.Config, online bool) (n *IpfsNode, err error) {
 	// session that simply doesn't return blocks
 	n.Blocks, err = bserv.NewBlockService(n.Datastore, n.Exchange)
 	if err != nil {
-		return nil, err
+		return nil, errors.Wrap(err)
 	}
 
 	n.DAG = merkledag.NewDAGService(n.Blocks)

core/datastore.go

 package core
 
 import (
-	"fmt"
-
 	ds "github.com/jbenet/go-ipfs/Godeps/_workspace/src/github.com/jbenet/go-datastore"
 	fsds "github.com/jbenet/go-ipfs/Godeps/_workspace/src/github.com/jbenet/go-datastore/fs"
 	ktds "github.com/jbenet/go-ipfs/Godeps/_workspace/src/github.com/jbenet/go-datastore/keytransform"
@@ -12,11 +10,12 @@ import (
 
 	config "github.com/jbenet/go-ipfs/config"
 	u "github.com/jbenet/go-ipfs/util"
+	"github.com/jbenet/go-ipfs/util/errors"
 )
 
 func makeDatastore(cfg config.Datastore) (u.ThreadSafeDatastoreCloser, error) {
 	if len(cfg.Type) == 0 {
-		return nil, fmt.Errorf("config datastore.type required")
+		return nil, errors.Errorf("config datastore.type required")
 	}
 
 	switch cfg.Type {
@@ -36,16 +35,17 @@ func makeDatastore(cfg config.Datastore) (u.ThreadSafeDatastoreCloser, error) {
 		return u.CloserWrap(syncds.MutexWrap(ktd)), nil
 	}
 
-	return nil, fmt.Errorf("Unknown datastore type: %s", cfg.Type)
+	return nil, errors.Errorf("Unknown datastore type: %s", cfg.Type)
 }
 
 func makeLevelDBDatastore(cfg config.Datastore) (u.ThreadSafeDatastoreCloser, error) {
 	if len(cfg.Path) == 0 {
-		return nil, fmt.Errorf("config datastore.path required for leveldb")
+		return nil, errors.Errorf("config datastore.path required for leveldb")
 	}
 
-	return lds.NewDatastore(cfg.Path, &lds.Options{
+	ds, err := lds.NewDatastore(cfg.Path, &lds.Options{
 		// TODO don't import ldbopts. Get from go-datastore.leveldb
 		Compression: ldbopts.NoCompression,
 	})
+	return ds, errors.Wrap(err)
 }

daemon2/daemon.go

@@ -6,13 +6,15 @@ import (
 
 	lock "github.com/jbenet/go-ipfs/Godeps/_workspace/src/github.com/camlistore/lock"
 	"github.com/jbenet/go-ipfs/util"
+	"github.com/jbenet/go-ipfs/util/errors"
 )
 
 // LockFile is the filename of the daemon lock, relative to config dir
 const LockFile = "daemon.lock"
 
 func Lock(confdir string) (io.Closer, error) {
-	return lock.Lock(path.Join(confdir, LockFile))
+	c, err := lock.Lock(path.Join(confdir, LockFile))
+	return c, errors.Wrap(err)
 }
 
 func Locked(confdir string) bool {