components-overview.adoc

Overview of bitcoind

The following diagram gives a brief overview of how some of the major components in bitcoind are related.

Warning

This diagram is not exhaustive and includes simplifications.

Note	dashed lines indicate optional components

bitcoind overview

flowchart LR
    bitcoind
    RPCServer -.-> bitcoind
    RESTServer -.-> bitcoind
    Node -----> bitcoind
    AddrMan --> Node
    CConnman --> Node
    Interfaces::Chain --> Node
    ChainstateManager --> Node
    NetGroupManager --> AddrMan
    CTxMemPool --> Node
    PeerManager --> Node
    Wallet -.-> bitcoind
    ScriptPubKeyMan --> Wallet
    WalletDatabase --> Wallet
    sqlite -.-> WalletDatabase
    BDB -.-> WalletDatabase
    Logger --> bitcoind
    ZMQ -.-> bitcoind
    BlockManager --> ChainstateManager
    LevelDB --> BlockManager

Table 1. Brief description of components in bitcoind overview

Component	Simplified description
AddrMan	Manage peers' network addresses
CConnman	Manage network connections to peers
Interfaces::Chain	Give clients access to chain state, fee rate estimates, notifications and allow tx submission
ChainstateManager	An interface for interacting with 1 or 2 chainstates (1. IBD-verified, 2. optional snapshot)
NetGroupManager	Manage net groups. Ensure we don’t connect to multiple nodes in the same ASN bucket
CTxMemPool	Validate and store (valid) transactions which may be included in the next block
PeerManager	Manage peer state and interaction e.g. processing messages, fetching blocks & removing for misbehaviour
BlockManager	Maintains a tree of blocks on disk (via LevelDB) to determine most-work tip
ScriptPubKeyMan	Manages scriptPubKeys in a wallet. Can give out new scriptPubKeys as well as call into a SigningProvider to sign transactions

bitcoin-cli overview

The following diagram gives a brief overview of the major components in bitcoin-cli.

Warning

This diagram is not exhaustive and includes simplifications.

bitcoin-cli overview

flowchart LR
    BaseRequestHandler["BaseRequestHandler()"]
    AddrInfoRequestHandler["AddrInfoRequestHandler()"]
    ConnectAndCallRPC["ConnectAndCallRPC()"]
    GetInfoRequestHandler["GetInfoRequestHandler()"]
    NetInfoRequestHandler["NetInfoRequestHandler()"]
    GenerateToAddressHandler["GenerateToAddressHandler()"]
    DefaultRequestHandler["DefaultRequestHandler()"]
    BaseRequestHandler --> AddrInfoRequestHandler --> ConnectAndCallRPC
    BaseRequestHandler --> GetInfoRequestHandler --> ConnectAndCallRPC
    BaseRequestHandler --> NetInfoRequestHandler --> ConnectAndCallRPC
    BaseRequestHandler --> GenerateToAddressHandler --> ConnectAndCallRPC
    BaseRequestHandler --> DefaultRequestHandler --> ConnectAndCallRPC
    ConnectAndCallRPC <---> bitcoin-cli
    ArgsManager --> bitcoin-cli

Wallet structure

The following diagram gives a brief overview of how the wallet is structured.

Warning

This diagram is not exhaustive and includes simplifications.

Note	dashed lines indicate optional components

Wallet structure overview

flowchart LR
    ScriptPubKeyMan --> DescriptorScriptPubKeyMan
    ScriptPubKeyMan --> LegacyScriptPubKeyMan
    subgraph Descriptor or Legacy wallet
    DescriptorScriptPubKeyMan
    LegacyScriptPubKeyMan
    end
    DescriptorScriptPubKeyMan -.-> CWallet
    LegacyScriptPubKeyMan -.-> CWallet
    Interfaces::Chain --> CWallet
    WalletDatabase --> CWallet
    cs_wallet{{cs_wallet}} ---> CWallet

    subgraph BDB or sqlite database
    BDB
    sqlite
    end
    BDB -.-> WalletDatabase
    sqlite -.-> WalletDatabase

    SigningProvider --> ScriptPubKeyMan
    WalletStorage --> ScriptPubKeyMan
    Scripts --> ScriptPubKeyMan
    Keys --> ScriptPubKeyMan

Table 2. Brief description of components

Component	Simplified description
WalletDatabase	Represents a single wallet. Handles reads and writes to disk
ScriptPubKeyMan	Base class for the below SPKM classes to override before being used by CWallet
DescriptorScriptPubKeyMan	A SPKM for descriptor-based wallets
LegacyScriptPubKeyMan	A SPKM for legacy wallets
SigningProvider	An interface for a KeyStore to sign transactions from
Interfaces::Chain	Give clients access to chain state, fee rate estimates, notifications and allow tx submission
cs_wallet	The primary wallet lock, held for atomic wallet operations