91 lines
4.3 KiB
Go
91 lines
4.3 KiB
Go
|
// Copyright 2016 The go-ethereum Authors
|
||
|
|
// This file is part of the go-ethereum library.
|
||
|
|
//
|
||
|
|
// The go-ethereum library is free software: you can redistribute it and/or modify
|
||
|
|
// it under the terms of the GNU Lesser General Public License as published by
|
||
|
|
// the Free Software Foundation, either version 3 of the License, or
|
||
|
|
// (at your option) any later version.
|
||
|
|
//
|
||
|
|
// The go-ethereum library is distributed in the hope that it will be useful,
|
||
|
|
// but WITHOUT ANY WARRANTY; without even the implied warranty of
|
||
|
|
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
||
|
|
// GNU Lesser General Public License for more details.
|
||
|
|
//
|
||
|
|
// You should have received a copy of the GNU Lesser General Public License
|
||
|
|
// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
|
||
|
|
|
||
|
|
/*
|
||
|
|
Package node sets up multi-protocol Ethereum nodes.
|
||
|
|
|
||
|
|
In the model exposed by this package, a node is a collection of services which use shared
|
||
|
|
resources to provide RPC APIs. Services can also offer devp2p protocols, which are wired
|
||
|
|
up to the devp2p network when the node instance is started.
|
||
|
|
|
||
|
|
|
||
|
|
Resources Managed By Node
|
||
|
|
|
||
|
|
All file-system resources used by a node instance are located in a directory called the
|
||
|
|
data directory. The location of each resource can be overridden through additional node
|
||
|
|
configuration. The data directory is optional. If it is not set and the location of a
|
||
|
|
resource is otherwise unspecified, package node will create the resource in memory.
|
||
|
|
|
||
|
|
To access to the devp2p network, Node configures and starts p2p.Server. Each host on the
|
||
|
|
devp2p network has a unique identifier, the node key. The Node instance persists this key
|
||
|
|
across restarts. Node also loads static and trusted node lists and ensures that knowledge
|
||
|
|
about other hosts is persisted.
|
||
|
|
|
||
|
|
JSON-RPC servers which run HTTP, WebSocket or IPC can be started on a Node. RPC modules
|
||
|
|
offered by registered services will be offered on those endpoints. Users can restrict any
|
||
|
|
endpoint to a subset of RPC modules. Node itself offers the "debug", "admin" and "web3"
|
||
|
|
modules.
|
||
|
|
|
||
|
|
Service implementations can open LevelDB databases through the service context. Package
|
||
|
|
node chooses the file system location of each database. If the node is configured to run
|
||
|
|
without a data directory, databases are opened in memory instead.
|
||
|
|
|
||
|
|
Node also creates the shared store of encrypted Ethereum account keys. Services can access
|
||
|
|
the account manager through the service context.
|
||
|
|
|
||
|
|
|
||
|
|
Sharing Data Directory Among Instances
|
||
|
|
|
||
|
|
Multiple node instances can share a single data directory if they have distinct instance
|
||
|
|
names (set through the Name config option). Sharing behaviour depends on the type of
|
||
|
|
resource.
|
||
|
|
|
||
|
|
devp2p-related resources (node key, static/trusted node lists, known hosts database) are
|
||
|
|
stored in a directory with the same name as the instance. Thus, multiple node instances
|
||
|
|
using the same data directory will store this information in different subdirectories of
|
||
|
|
the data directory.
|
||
|
|
|
||
|
|
LevelDB databases are also stored within the instance subdirectory. If multiple node
|
||
|
|
instances use the same data directory, openening the databases with identical names will
|
||
|
|
create one database for each instance.
|
||
|
|
|
||
|
|
The account key store is shared among all node instances using the same data directory
|
||
|
|
unless its location is changed through the KeyStoreDir configuration option.
|
||
|
|
|
||
|
|
|
||
|
|
Data Directory Sharing Example
|
||
|
|
|
||
|
|
In this exanple, two node instances named A and B are started with the same data
|
||
|
|
directory. Mode instance A opens the database "db", node instance B opens the databases
|
||
|
|
"db" and "db-2". The following files will be created in the data directory:
|
||
|
|
|
||
|
|
data-directory/
|
||
|
|
A/
|
||
|
|
nodekey -- devp2p node key of instance A
|
||
|
|
nodes/ -- devp2p discovery knowledge database of instance A
|
||
|
|
db/ -- LevelDB content for "db"
|
||
|
|
A.ipc -- JSON-RPC UNIX domain socket endpoint of instance A
|
||
|
|
B/
|
||
|
|
nodekey -- devp2p node key of node B
|
||
|
|
nodes/ -- devp2p discovery knowledge database of instance B
|
||
|
|
static-nodes.json -- devp2p static node list of instance B
|
||
|
|
db/ -- LevelDB content for "db"
|
||
|
|
db-2/ -- LevelDB content for "db-2"
|
||
|
|
B.ipc -- JSON-RPC UNIX domain socket endpoint of instance A
|
||
|
|
keystore/ -- account key store, used by both instances
|
||
|
|
*/
|
||
|
|
package node
|