Commit Graph

130 Commits

Author SHA1 Message Date
Olaoluwa Osuntokun
785efcfaa2
channeldb: also ignore the EOF error when trying to read ExtraOpaqueBytes
In this commit, we account for the additional case wherein the
announcement hasn't yet been written with the extra zero byte to
indicate that there aren't any remaining bytes to be read. Before this
commit, we accounted for the case where the announcement was written
with the extra byte, but now we ensure that legacy nodes that upgrade
will be able to boot properly.
2018-09-05 16:42:23 -07:00
Olaoluwa Osuntokun
16b5a67c3a
Merge pull request #1842 from wpaulino/dedup-chan-updates-horizon
channeldb: dedup channel edges returned from ChanUpdatesInHorizon
2018-09-04 21:24:40 -07:00
Olaoluwa Osuntokun
48072f8e82
channeldb: add limit on the max number of opaque bytes per announcement
In this commit, we add a new limit on the largest number of extra opaque
bytes that we'll allow to be written per vertex/edge. We do this in
order to limit the amount of disk space that we expose, as it's possible
that nodes may start to pad their announcements adding an additional
externalized cost as nodes may need to continue to store and relay these
large announcements.
2018-09-04 20:52:45 -07:00
Olaoluwa Osuntokun
f5c582d8d7
channeldb: add new ExtraOpaqueData to edge policy+update and node ann
In this commit, we add a mirror set of fields to the ones we recently
added to the set of gossip wire messages. With these set of fields in
place, we ensure that we'll be able to properly store and re-validate
gossip messages that contain a set of extra/optional fields.
2018-09-04 20:52:43 -07:00
Wilmer Paulino
3f58c2dea4
channeldb/graph: dedup channel edges returned from ChanUpdatesInHorizon
In this commit, we ensure that we de-duplicate the set of channel edges
returned from ChanUpdatesInHorizon. Other subsystems within lnd use this
method to retrieve and send all the channels with updates within a time
series to network peers. However, since the method looks at the edge
update index, which can include up to two entries per edge for each
policy, it's possible that we'd send channel announcements and updates
twice, causing extra bandwidth.
2018-09-04 18:48:21 -07:00
Wilmer Paulino
2f22e6c35f
channeldb/graph: properly determine old update timestamp for an edge
In this commit, we fix a lingering issue within the edge update index
where entries were not being properly pruned due to an incorrect
calculation of the offset of an edge's last update time. Since the
offset is being determined from the end to the start, we need to
subtract all the fields after an edge policy's last update time from the
total amount of bytes of the serialized edge policy to determine the
correct offset. This was also slightly off as the edge policy included
an extra byte, which has been fixed in the previous commit.

Instead of continuing the slicing approach however, we'll switch to
deserializing the raw bytes of an edge's policy to ensure this doesn't
happen in the future when/if the serialization methods change or extra
data is included.
2018-09-04 18:33:38 -07:00
Wilmer Paulino
492d581df6
channeldb/graph: fix off-by-one public key slice
In this commit, we fix an off-by-one error when slicing the public key
from the serialized node info byte slice. This would cause us to write
an extra byte to all edge policies. Even though the values were read
correctly, when attempting to calculate the offset of an edge's update
time going backwards, we'd always be incorrect, causing us to not
properly prune the edge update index.
2018-09-04 18:31:38 -07:00
Wilmer Paulino
06344da62e
channeldb/graph: refactor UpdateEdgePolicy to use existing db transaction 2018-09-04 18:31:37 -07:00
Wilmer Paulino
aa3e2b6ba4
channeldb/graph: identify edge chan id on failure 2018-09-04 18:31:36 -07:00
Olaoluwa Osuntokun
9353ab00b1
channeldb: ensure that we remove update index entries for nodes upon deletion 2018-08-16 18:22:55 -07:00
Olaoluwa Osuntokun
90cdc9da8f
channeldb: add String() method for EdgePoint
In this commit we fix a minor logging artifact. After the switch to
EdgePoint, the FilteredChainView implementations will try to log the
struct directly, as prior they would have an outpoint object. We restore
this behavior by adding a String() method to EdgePoint which will simply
proxy through to the outpoint so we can log that directly.
2018-08-15 21:43:39 -07:00
Olaoluwa Osuntokun
0f3c0ccf85
channeldb: add new FetchOtherNode method to ChannelEdgeInfo
In this commit, we add a new method to the ChannelEdgeInfo that will
allow the path finding logic to get the node opposite the pivot node
without first creating a new db transaction. The new method is able to
use an existing db transaction, or create a new one if needed.
2018-08-09 20:47:01 -07:00
Olaoluwa Osuntokun
ce7bfae4f7
channeldb: ensure we always check error from fetchChanEdgePolicy 2018-08-09 20:46:04 -07:00
Olaoluwa Osuntokun
0109672835
channeldb: add new db field for ChannelEdgeInfo to allow new methods 2018-08-09 20:45:39 -07:00
Joost Jager
6c918a1806 channeldb: store unknown policies in database
The commit ensures that for every channel, there will always
be two entries in the edges bucket. If the policy from one or
both ends of the channel is unknown, it is marked as such.

This allows efficient lookup of incoming edges. This is
required for backwards payment path finding.
2018-08-09 20:23:40 -07:00
Conner Fromknecht
cf2c371042
multi: fix linting errors 2018-08-02 18:20:50 -07:00
Olaoluwa Osuntokun
d129e7c890
channeldb: update ChannelView to return new EdgePoint struct
In this commit, we update the ChannelView method to be compatible with
the new set of interfaces that require the script to be passed in in
addition to the outpoint. In order to do this, we introduce a new
EdgePoint struct which packages together a channel point along with the
funding pkScript. Along the way, we've copied over a utility method from
the lnwallet package to avoid having to deal with an import cycle.
2018-07-31 21:28:54 -07:00
Olaoluwa Osuntokun
2e75499787
channeldb+routing: move adding shell nodes into db txn of AddChannelEdge
In this commit, we fix a slight race condition that can occur when we go
to add a shell node for a node announcement, but then right afterwards,
a new block arrives that causes us to prune an unconnected node. To
ensure this doesn't happen, we now add shell nodes within the same db
transaction as AddChannelEdge. This ensures that the state is fully
consistent and shell nodes will be added atomically along with the new
channel edge.

As a result of this change, we no longer need to add shell nodes within
the ChannelRouter, as the database will take care of this operation as
it should.
2018-07-22 21:02:53 -07:00
Olaoluwa Osuntokun
8519ea869d
channeldb: add logging for nodes pruned from the channel graph 2018-07-22 21:00:51 -07:00
Olaoluwa Osuntokun
6bf15e8f2b
channeldb: fix bug in pruneGraphNodes by switching to using ref counting
In this commit, we fix an existing bug in the pruneGraphNodes method.
Before this commit, if a node was involved in a channel, but only one of
the edges was advertised, then either it, or the other node would be
erroneously pruned from the graph. They shouldn't be pruned as there's
still an edge connecting the, although only 1/2 of the edge is actually
advertised.

In order to fix this, we'll now do two passes: the first pass will
populate a ref count map of all known nodes in the graph, the second
pass will increment the ref count each time a node is found in the
graph. With this two pass method, we ensure that nodes are only deleted
if there are absolutely no edges pointing to them within the graph.
2018-07-22 18:59:36 -07:00
Olaoluwa Osuntokun
0645261e5e
channeldb: add nwe PruneGraphNodes method to prune unconnected nodes 2018-07-21 19:49:59 -07:00
Olaoluwa Osuntokun
3a465c64b5
channeldb: modify pruneGraphNodes to prune nodes if no edges exist 2018-07-21 19:49:16 -07:00
Wilmer Paulino
0e4d350e56
channeldb: prune nodes with no open channels left from the graph 2018-07-17 17:35:29 -07:00
Wilmer Paulino
959618d596
channeldb: refactor methods to allow using existing db transaction 2018-07-17 17:35:26 -07:00
Olaoluwa Osuntokun
6f60f139f4 multi: switch over import paths from roasbeef/* to btcsuite/* 2018-07-13 17:05:39 -07:00
Olaoluwa Osuntokun
dd4cab054d
channeldb: ensure items from the update index are actually deleted
In this commit, we fix an existing bug in the new graph query sync
feature. Before this commit, when a block is pruned, we would never
actually delete the update index entries. This is due to the fact that
we would attempt to delete the entries from the update index _after_ we
had already removed the edges from the update index.

We fix this by simply swapping the order: first we delete from the
update index, then we delete the edges themselves. A test ensuring that
the entires are cleared (which failed before this commit), has been
added.
2018-06-05 17:30:56 -07:00
Olaoluwa Osuntokun
70dffe7e99
channeldb: ensure that when we delete a channel we delete entry in edge update index
In this commit, we ensure that all indexes for a particular channel have
any relevant keys deleted once a channel is removed from the database.
Before this commit, if we pruned a channel due to closing, then its
entry in the channel update index would ever be removed.
2018-05-31 16:30:59 -07:00
Olaoluwa Osuntokun
baed4d1f47
channeldb: add new methods required to implement new discovery.ChannelGraphTimeSeries interface
In this commit, we add a series of methods, and a new database index
that we'll use to implement the new discovery.ChannelGraphTimeSeries
interface interface. The primary change is that we now maintain two new
indexes tracking the last update time for each node, and the last update
time for each edge. These two indexes allow us to implement the
NodeUpdatesInHorizon and ChanUpdatesInHorizon methods. The remaining
methods added simply utilize the existing database indexes to allow us to
respond to any peer gossip range queries.

A set of new unit tests has been added to exercise the added logic.
2018-05-31 16:30:54 -07:00
practicalswift
663c396235 multi: fix a-vs-an typos 2018-04-17 19:02:04 -07:00
Olaoluwa Osuntokun
800eea931f
build+multi: switch from bolt to bbolt
In this commit, we switch from boltbd/bolt to coreos/bbolt as the
former is no longer being actively maintained.
2018-03-10 19:01:13 -08:00
practicalswift
b8e1351cf3 multi: fix some recently introduced typos 2018-02-18 15:27:29 -08:00
Olaoluwa Osuntokun
3e422fedd3
channeldb: further GC optimizations during path finding
In this commit, we made a series of modification to the way we handle
reading edges and vertexes from disk, in order to reduce the amount of
garbage generated:
  1. Properly use PubKeyBytes are required rather than PubKey()
  2. Return direct structs rather than pointers, and leave it to the
runtime to perform escape analysis.
  3. In-line the former readSig() method when reading sigs from disk.
2018-02-12 16:17:14 -08:00
Olaoluwa Osuntokun
e578cea375
channeldb: fix linter errors 2018-02-06 20:14:34 -08:00
Olaoluwa Osuntokun
5e9166e478
channeldb: use raw pub keys and signatures directly in vertex/edge structs
In this commit, we make an API change that’s meant to reduce the amount
of garbage we generate when doing pathfinding or syncing nodes with our
latest graph state. Before this commit, we would always have to fully
decode the public key and signatures when reading a edge or vertex
struct. For the edges, we may need several EC operations to fully
decode all the pubkeys. This has been seen to generate a ton of
garbage, as well as slow down path finding a good bit.

To remedy this, we’ll now only ever read the *raw* bytes from disk. In
the event that we actually need to verify a signature (or w/e), only
*then* will we fully decode everything.
2018-02-06 20:14:31 -08:00
Daniel McNally
8543497dcc multi: fixing it's/its typos in comments 2018-02-06 19:13:07 -08:00
practicalswift
a93736d21e multi: comprehensive typo fixes across all packages 2018-02-06 19:11:11 -08:00
MeshCollider
d8f453d9dc channeldb: remove address resolution from channeldb 2018-02-05 17:37:46 -08:00
Olaoluwa Osuntokun
a94648e9dc
channeldb: properly use a read-transaction in FetchChannelEdgesByOutpoint
Before this commit, we’d unnecessarily use a write transaction within
the FetchChannelEdgesByOutpoint. This is wasteful as the function only
actually reads items from the database, and doesn’t attempt any
mutations at all.
2018-01-28 14:48:57 -08:00
Matt Drollette
adf0d98194 multi: fix several typos in godoc comments 2017-12-17 18:40:05 -08:00
Olaoluwa Osuntokun
9b53d7bd95
channeldb: treat Flags field in ChannelEdgePolicy as a bitfield 2017-11-30 22:41:54 -08:00
Johan T. Halseth
b26560e0f4
channeldb: add DisconnectBlockAtHeight
This commit adds the method DisconnectBlockAtHeight to the channel
graph database, making it possible to "rewind" the database in case
a block is disconnected from the main chain. To accomplish this,
a prune log is introduced, making it possible to keep track of the
point in time where the database was pruned. This is necessary for
the case where lnd might wake up on a stale branch, and must "walk
backwards" on this branch after it finds a common block fro the
graph database and the new main chain.
2017-11-03 00:05:19 +01:00
Jim Posen
9fd77a6e40 multi: Update lnd to use new feature vector API. 2017-10-17 22:47:20 -07:00
Olaoluwa Osuntokun
5eb3406b19
channeldb: add new Database method to ChannelGraph 2017-10-10 22:19:26 -07:00
Olaoluwa Osuntokun
81cd954cfc
discovery: don't prune *our* channels during retransmission tick
This commit modifies the recently modified logic for self-channel
retransmission to exclude pruning *our* channels which haven’t been
updated since the broadcastInterval. Instead, we only re-broadcast
channels of ours that haven’t been updated in 24 hours.
2017-10-04 20:46:08 -07:00
halseth
8693e8babc channeldb: check chanIndex bucket for nilness instead of edges 2017-09-19 05:40:29 +02:00
Conner Fromknecht
6ffe33f01a lnw+ba+utxon+cdb: reverts OutPoint and TxOut encoding 2017-08-25 17:56:50 -07:00
Philip Hayes
f0aa186a56 channeldb+utxonursery+lnwire: use lnwire's OutPoint,TxOut serialization 2017-08-25 17:56:50 -07:00
Olaoluwa Osuntokun
76302a136b
channeldb: in node.ForEachChannel return incoming/outgoing edges
This commit modifies the node.ForEachChannel to *also* return the
incoming edge as well as the outgoing edge. We make this modification
as when we’re doing path finding, we need to return the incoming edge
as well, since we need to use the to properly compute the time lock and
fees for transit on that edge.
2017-08-22 00:52:25 -07:00
Olaoluwa Osuntokun
35d9dc8092
channeldb: add ChainHash to ChannelEdgeInfo to match BOLT-0007 2017-08-22 00:52:22 -07:00
Olaoluwa Osuntokun
59aae249dc
channeldb: use lnwire.MilliSatoshi within the ChannelEdgePolicy struct 2017-08-22 00:52:20 -07:00
Olaoluwa Osuntokun
8abba7eafc
channeldb: add TODO to add storage for onion adds 2017-08-10 21:15:55 -07:00
Johan T. Halseth
bd0465ee1d channeldb: support adding partial LightningNodes to graph.
Adds a HaveNodeAnnouncement field to the LightningNode
struct, which is used to indicate if we have gotten
all the necessary information to fill the remaining
fields in the struct. If we haven't gotten a node
announcement for this specific node, then we only
know the pubkey, and can only fill that field in
the struct. Still, we should be able to add it to the
channel graph and use it for routes, as long as we
know about channels to this node.
2017-08-02 15:58:58 -07:00
Olaoluwa Osuntokun
333373f78f
channeldb: add new ChannelView method to the ChannelGraph
This commit introduces a new method to the ChannelGraph struct:
ChannelView. This struct returns all the outpoints that represent the
set of active channels within the network. The set of items returned by
this new method will possibly shrink with each call to `PruneGraph`,
and possibly be expanded by each call to `AddChannelEdge`.

The graph pruning tests have been updated to ensure the description
above holds true.
2017-05-11 15:20:23 -07:00
Olaoluwa Osuntokun
b96b180b0b
channeldb: modify ForEachNode/ForEachChannel to accept a db txn
This commit modifies the ForEachNode on the ChannelGraph and
ForEachChannel on the LightningNode struct to accept a database
transaction as its first argument. With this change, it’ll now be
possible to implement graph traversals that typically required a nested
loop with all the vertex loaded into memory using the callback API
instead:
c.ForEachNode(nil, func(tx, node) {
    node.ForEachChannel(tx, func(…) {
    })
})
2017-04-14 13:14:09 -07:00
Andrey Samokhvalov
07076cce21 routing+channeldb: add AddProof method
Originally we adding the edge without proof in order to able to use it
for payments path constrcution. This method will allow us to populate
the announcement proof after the exchange of the half proofs and
constrcutrion of full proof finished.
2017-03-29 19:49:05 -07:00
Andrey Samokhvalov
19174ebdfd channeldb: add storing of node signature and add edge signature
In order to properly announce the channel the announcements proofs
should be persistent in boltdb.
2017-03-29 19:49:05 -07:00
Andrey Samokhvalov
2105a06a26 channeldb: add ability to store empty auth proof
In case if the channel shouldn't be announced to the rest of the network
the proof, which is needed to announce the channel, will not be
populated, fot that reason the ability to store the empty proof has
been added.
2017-03-29 19:49:05 -07:00
Andrey Samokhvalov
7a9a52c7b9 channeldb: add ErrEdgeAlreadyExist error 2017-03-29 19:49:05 -07:00
bryanvu
085b7333cb lnwire: add support for Features in NodeAnnouncement
Add support for Features in NodeAnnouncment according to spec.
2017-03-29 12:03:43 -07:00
bryanvu
9ffac9eae1 lnwire: update NodeAnnouncement to handle multiple addresses
This commit modifies address handling in the NodeAnnouncement struct,
switching from net.TCPAddr to []net.Addr. This enables more flexible
address handling with multiple types and multiple addresses for each
node. This commit addresses the first part of issue #131 .
2017-03-29 12:03:43 -07:00
Andrey Samokhvalov
61991a1c89 lnd: fix latest goclean.sh lint warning 2017-03-13 16:30:23 -07:00
Andrey Samokhvalov
143a6e01bb lnd: fix unconvert warnings 2017-03-13 16:30:23 -07:00
Olaoluwa Osuntokun
7bdf02bc9e
routing: modify path finding routines use new EdgeInfo/EdgePolicy
This commit modifies the path finding routines to properly use the new
channel edge related API exposed by the database. Additionally, a new
type `ChannelHop` has been introduced which couples an edges routing
policy with the capacity and origin chain of the channel.
2017-03-08 14:25:05 -08:00
Olaoluwa Osuntokun
deceae8fe4
channeldb: PruneGraph now returns the channels closed
This commit alters the return value of PrunedGraph to me a bit more
useful: the function now returns all the channels that were closed when
processing the block (slice of spent outpoints). With this information,
callers gain greater visibility into exactly which channels were
closed. This can be used in higher levels to present detailed summaries
of how blocks affect closed channels.
2017-03-05 19:20:57 -06:00
Olaoluwa Osuntokun
2c29a20a8d
channeldb: split ChannelEdge into two structs, info and policy
This commit splits the prior ChannelEdge struct into two distinct
structs: ChannelEdgeInfo and ChannelEdgePolicy. The info structs stores
the _full_ information that was used to advertise the channel, while
the policy struct contains the information that’s needed in order to
use the information for routing purposes.

With this split we can eliminate a number of hacks within the rest of
the codebase that were added as a result of data unavailability if one
or neither edge was present.

Finally a bit of field renaming has taken place (Exipiry ->
TimeLockDelta), etc.
2017-03-05 19:18:34 -06:00
Olaoluwa Osuntokun
f623729b64
channeldb: fix panic in query for nonexistent channel ID
This commit fixes a panic that would arise when the daemon attempts to
query for a channel that doesn’t currently exist. The bug was the
result of a typo which checked for the nil existence of the incorrect
variable.
2017-01-22 14:28:36 -08:00
Trevin Hofmann
40c7bac3aa multi: fix a variety of typos throughout the repo 2017-01-17 17:02:56 -08:00
Olaoluwa Osuntokun
7a36fb4562
channeldb: fix assumption that both channel edges will always be advertised
This commit fixes a prior bug in the graph database due to an invalid
assumption that both channel edges would _always_ be advertised. This
assumption is invalid, as it’s up to a node’s policy if the advertise
their direction of the channel.

The fix for this assumption is straight forward: ErrEdgeNotFound is no
longer a critical error, instead a nil pointer will now be passed into
the passed callback function.
2017-01-17 13:01:19 -08:00
Olaoluwa Osuntokun
5c41167858
channeldb: return correct error when unable to find node 2017-01-17 12:57:56 -08:00
Olaoluwa Osuntokun
5f2f77e873
channeldb: fix typo in AddChannelEdge 2017-01-09 19:02:37 -08:00
Olaoluwa Osuntokun
5affed38fc
multi: update btcsuite API's to latest upstream changes
This commit makes a large number of minor changes concerning API usage
within the deamon to match the latest version on the upstream btcsuite
libraries.

The major changes are the switch from wire.ShaHash to chainhash.Hash,
and that wire.NewMsgTx() now takes a paramter indicating the version of
the transaction to be created.
2017-01-05 13:56:34 -08:00
Olaoluwa Osuntokun
630afbdc93
channeldb: don't return error from HasChannelEdge if single edge doesn't exist
This commit modifies the error propagating behavior within the
HasChannelEdge struct. Rather than exiting the function early when a
single edge isn’t found, we instead continue to also possibly retrieve
the second directional edge.

With this change, we avoid a potential infinite gossiping loop in the
routing package that would result if we’d seen one edge but not the
other. In this case the timestamps returned for *both* edges would
always be zero, causing the daemon to always accept and rebroadcast the
announcement putting all other connected lnd’s into the same loop.
2016-12-30 16:35:30 -08:00
Olaoluwa Osuntokun
afd2323d10
channeldb: use a read-txn rather than a write-txn in FetchChannelEdgesByID
This commit modifies the FetchChannelEdgesByID slightly to use a
read-only transaction rather than a write-only transaction. As a result
we’ll no longer extraneously consume a writer’s slot when we’re only
reading data from the database.
2016-12-27 16:44:17 -08:00
Olaoluwa Osuntokun
e0d94b545c
channeldb: return true for HasChannelEdge unconditionally if edge exists
This commit modifies the HasChannelEdge function to _always_ return
true if we know of the channel edge, meaning that it was previously
added on announce.

This change fixes a minor bug present in the code which would result in
extraneous re-transmissions of updates received by the new routing
package.
2016-12-27 16:44:15 -08:00
Olaoluwa Osuntokun
1103e252be
channeldb: add method to lookup a channel ID by it's funding outpoint
This commit adds a utility method whcih utilizes the edge index bucket
and allows caller to look up the channel ID of a channel by its funding
outpoint. This can be used to populate RPC’s with additional
information and also to provide users with an additional query
interface to build channel explorers, etc.
2016-12-27 16:44:13 -08:00
Olaoluwa Osuntokun
42c90794ac
channeldb: return proper error in ChannelGraph.ForEachChannel()
This commit fixes a minor bug in the ForEachChannel method of the
ChannelGraph struct. Rather than ErrGraphNoEdgesFound being returned if
either of the edge related buckets hadn’t been created yet,
ErrGraphNodesNotFound was being returned.

To fix this bug, we now properly return ErrGraphNoEdgesFound.
Additionally a mental note to roasbeef has been left as the current
code currently assumes that eventually both directions of the channel
edge will be advertised. However, this may not necessarily be the case
in a live network, since a side chooses to preferentially advertise a
channel or not.
2016-12-27 16:43:53 -08:00
Olaoluwa Osuntokun
000c334e63
channeldb: add HasLightningNode+HasChannelEdge methods to ChannelGraph
This commit adds to new functions to the ChannelGraph struct which
allow the callers to query for the existence or non-existence of a
vertex (node) or edge (channel) within the graph. In addition to
returning whether the edge exists, the functions will also return the
last time the state has been modified for the edge or vertex. This will
allow callers to ensure that only the most up to date state is
committed to disk.
2016-12-27 16:43:29 -08:00
Olaoluwa Osuntokun
12538ea922
channeldb: add support for channel graph pruning
This commit adds support for channel graph pruning, which is the method
used to keep the channel graph in sync with the current UTXO state. As
the channel graph is essentially simply a subset of the UTXO set, by
evaluating the channel graph with the set of outfits spent within a
block, then we’re able to prune channels that’ve been closed by
spending their funding outpoint. A new method `PruneGraph` has been
provided which implements the described functionality.

Upon start up any upper routing layers should sync forward in the chain
pruning the channel graph with each newly found block. In order to
facilitate such channel graph reconciliation a new method `PruneTip`
has been added which allows callers to query current pruning state of
the channel graph.
2016-12-27 16:43:12 -08:00
Olaoluwa Osuntokun
d5423f007d
channeldb: add option to re-use existing db transaction for graph traversals
This commit modifies the LightningNode.ForEachChannel method to give
the caller the option of re-using an existing database transaction
instead of always creating a new db transaction with each invocation.
Internally boltdb will run into an error/dead-lock if a nested
transaction is attempted.

Such an action might be attempted if one were to use the traversal
functions in  a path finding algorithm. Therefore in order to avoid
that after, we now allow the re-use of transactions to facilitate
nested calls to ForEachChannel.
2016-12-27 16:43:00 -08:00
Olaoluwa Osuntokun
e39dc9eec1
channeldb: add storage of an on-disk directed channel graph
This commit introduces a new capability to the database: storage of an
on-disk directed channel graph. The on-disk representation of the graph
within boltdb is essentially a modified adjacency list which separates
the storage of the edge’s existence and the storage of the edge
information itself.

The new objects provided within he ChannelGraph carry an API which
facilitates easy graph traversal via their ForEach* methods. As a
result, path finding algorithms will be able to be expressed in a
natural way using the range methods as a for-range language extension
within Go.

Additionally caching will likely be added either at this layer or the
layer above (the RoutingManager) in order keep queries and outgoing
payments speedy. In a future commit a new set of RPC’s to query the
state of a particular edge or node will also be added.
2016-12-07 22:50:19 -08:00