github.com/aigarnetwork/aigar@v0.0.0-20191115204914-d59a6eb70f8e/node/doc.go (about)

     1  //  Copyright 2018 The go-ethereum Authors
     2  //  Copyright 2019 The go-aigar Authors
     3  //  This file is part of the go-aigar library.
     4  //
     5  //  The go-aigar library is free software: you can redistribute it and/or modify
     6  //  it under the terms of the GNU Lesser General Public License as published by
     7  //  the Free Software Foundation, either version 3 of the License, or
     8  //  (at your option) any later version.
     9  //
    10  //  The go-aigar library is distributed in the hope that it will be useful,
    11  //  but WITHOUT ANY WARRANTY; without even the implied warranty of
    12  //  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
    13  //  GNU Lesser General Public License for more details.
    14  //
    15  //  You should have received a copy of the GNU Lesser General Public License
    16  //  along with the go-aigar library. If not, see <http://www.gnu.org/licenses/>.
    17  
    18  /*
    19  Package node sets up multi-protocol Ethereum nodes.
    20  
    21  In the model exposed by this package, a node is a collection of services which use shared
    22  resources to provide RPC APIs. Services can also offer devp2p protocols, which are wired
    23  up to the devp2p network when the node instance is started.
    24  
    25  
    26  Resources Managed By Node
    27  
    28  All file-system resources used by a node instance are located in a directory called the
    29  data directory. The location of each resource can be overridden through additional node
    30  configuration. The data directory is optional. If it is not set and the location of a
    31  resource is otherwise unspecified, package node will create the resource in memory.
    32  
    33  To access to the devp2p network, Node configures and starts p2p.Server. Each host on the
    34  devp2p network has a unique identifier, the node key. The Node instance persists this key
    35  across restarts. Node also loads static and trusted node lists and ensures that knowledge
    36  about other hosts is persisted.
    37  
    38  JSON-RPC servers which run HTTP, WebSocket or IPC can be started on a Node. RPC modules
    39  offered by registered services will be offered on those endpoints. Users can restrict any
    40  endpoint to a subset of RPC modules. Node itself offers the "debug", "admin" and "web3"
    41  modules.
    42  
    43  Service implementations can open LevelDB databases through the service context. Package
    44  node chooses the file system location of each database. If the node is configured to run
    45  without a data directory, databases are opened in memory instead.
    46  
    47  Node also creates the shared store of encrypted Ethereum account keys. Services can access
    48  the account manager through the service context.
    49  
    50  
    51  Sharing Data Directory Among Instances
    52  
    53  Multiple node instances can share a single data directory if they have distinct instance
    54  names (set through the Name config option). Sharing behaviour depends on the type of
    55  resource.
    56  
    57  devp2p-related resources (node key, static/trusted node lists, known hosts database) are
    58  stored in a directory with the same name as the instance. Thus, multiple node instances
    59  using the same data directory will store this information in different subdirectories of
    60  the data directory.
    61  
    62  LevelDB databases are also stored within the instance subdirectory. If multiple node
    63  instances use the same data directory, opening the databases with identical names will
    64  create one database for each instance.
    65  
    66  The account key store is shared among all node instances using the same data directory
    67  unless its location is changed through the KeyStoreDir configuration option.
    68  
    69  
    70  Data Directory Sharing Example
    71  
    72  In this example, two node instances named A and B are started with the same data
    73  directory. Node instance A opens the database "db", node instance B opens the databases
    74  "db" and "db-2". The following files will be created in the data directory:
    75  
    76     data-directory/
    77          A/
    78              nodekey            -- devp2p node key of instance A
    79              nodes/             -- devp2p discovery knowledge database of instance A
    80              db/                -- LevelDB content for "db"
    81          A.ipc                  -- JSON-RPC UNIX domain socket endpoint of instance A
    82          B/
    83              nodekey            -- devp2p node key of node B
    84              nodes/             -- devp2p discovery knowledge database of instance B
    85              static-nodes.json  -- devp2p static node list of instance B
    86              db/                -- LevelDB content for "db"
    87              db-2/              -- LevelDB content for "db-2"
    88          B.ipc                  -- JSON-RPC UNIX domain socket endpoint of instance B
    89          keystore/              -- account key store, used by both instances
    90  */
    91  package node