EOSIO通过插件存储账号余额到Mongo

通过mongo_db_plugin存储账号余额到mongodb

我们这里以存储eosio.tokenEOS余额为例,思路是在发生transfer的时候,我们捕获该action,然后更新双方的余额。

首先,在class mongo_db_plugin_impl中声明我们需要的变量和函数

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    static const std::string accounts_col;
static const std::string pub_keys_col;
static const std::string account_controls_col;
+
+ // for get currency balance
+ mongocxx::collection _currency_balance; // mongo集合的handle
+ static const std::string currency_balance_col; // 将存放mongo集合的名称
+ chain_plugin* chain_plug_handle; // chain_plugin 中 get_currency_balance 可以帮助我们获取余额信息
+ void update_currency_balance( const chain::action_trace& ); // 我们的操作放到这里进行

给集合取名为currency_balance

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 const std::string mongo_db_plugin_impl::account_controls_col = "account_controls";
+const std::string mongo_db_plugin_impl::currency_balance_col = "currency_balance"; // mongo中集合将显示的是这个

mongo_db_plugin_impl::consume_blocks中初始化handle

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       _account_controls = mongo_conn[db_name][account_controls_col];
+ _currency_balance = mongo_conn[db_name][currency_balance_col];

mongo_db_plugin_impl::init()中给集合定义一个索引

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             account_controls.create_index( bsoncxx::from_json( R"xxx({ "controlling_account" : 1 })xxx" ));

+ // currency_balance index
+ auto currency_balance = mongo_conn[db_name][currency_balance_col];
+ currency_balance.create_index( bsoncxx::from_json( R"xxx({ "name" : 1 })xxx" )); // name字段索引为升序
+ currency_balance.create_index( bsoncxx::from_json( R"xxx({ "balance" : -1 })xxx" )); // balance字段索引为降序
+
} catch (...) {
handle_mongo_exception( "create indexes", __LINE__ );

mongo_db_plugin::plugin_initialize中实例化chain_plug_handle

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          auto& chain = chain_plug->chain();
my->chain_id.emplace( chain.get_chain_id());

+ // 给 chain_plug_handle 实例化
+ my->chain_plug_handle = chain_plug;
+
my->accepted_block_connection.emplace( chain.accepted_block.connect( [&]( const chain::block_state_ptr& bs ) {
my->accepted_block( bs );
} ));

定义我们的update_currency_balance函数

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+void mongo_db_plugin_impl::update_currency_balance( const chain::action_trace& atrace ) {
+ using namespace bsoncxx::types;
+ using bsoncxx::builder::basic::kvp;
+ using bsoncxx::builder::basic::make_document;
+
+ auto receiver = atrace.receipt.receiver;
+ if ( atrace.act.account == name("eosio.token") && atrace.act.name == name("transfer") ) {
+ chain_apis::read_only::get_currency_balance_params params = chain_apis::read_only::get_currency_balance_params {
+ .code = name("eosio.token"),
+ .account = receiver,
+ .symbol = "EOS",
+ };
+
+ chain_apis::read_only ro_api = chain_plug_handle->get_read_only_api();
+ vector<asset> asserts = ro_api.get_currency_balance( params );
+ if ( !asserts.empty() ) {
+ asset balance = asserts.at(0);
+ auto now = std::chrono::duration_cast<std::chrono::milliseconds>(
+ std::chrono::microseconds{fc::time_point::now().time_since_epoch().count()} );
+
+ // ilog( "${a}'s balance: ${b}", ("a", atrace.receipt.receiver.to_string())("b", balance.to_string()) );
+
+ mongocxx::options::update update_opts{};
+ update_opts.upsert( true );
+
+ const double balance_real = balance.to_real();
+ const string receiver_str = receiver.to_string();
+
+ auto update = make_document(
+ kvp( "$set", make_document( kvp( "name", receiver_str),
+ kvp( "balance", balance_real),
+ kvp( "createdAt", b_date{now} ))
+ )
+ );
+
+ try {
+ if( !_currency_balance.update_one( make_document( kvp( "name", receiver_str )), update.view(), update_opts )) {
+ EOS_ASSERT( false, chain::mongo_db_update_fail, "Failed to insert account ${n}", ("n", receiver));
+ }
+ } catch (...) {
+ handle_mongo_exception( "update_currency", __LINE__ );
+ }
+ }
+ }
+}
+
mongo_db_plugin_impl::mongo_db_plugin_impl()
{
}

mongodb-wipe的时候,应该删除集合,在mongo_db_plugin_impl::wipe_database添加如下

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    auto pub_keys = mongo_conn[db_name][pub_keys_col];
auto account_controls = mongo_conn[db_name][account_controls_col];
+ auto currency_balance = mongo_conn[db_name][currency_balance_col];

pub_keys.drop();
account_controls.drop();
+ currency_balance.drop();
ilog("done wipe_database");

准备好了之后,重新./eosio_build.sh,然后使用该nodeos重启节点(当然重启节点前需要配置好mongo插件,并且sudo mongod启动了mongo服务)。
通过shell查看mongo结果:

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$ mongo

> show dbs
EOS 0.093GB
...

> use EOS
switched to db EOS

> show collections
account_controls
accounts
action_traces
block_states
blocks
currency_balance
pub_keys
transaction_traces
transactions
// 通过上面show collections可以看到我们自定义的currency_balance集合了

// 按照balance降序显示
> db.currency_balance.find().sort({balance:-1}).pretty()
{
"_id" : ObjectId("5bf684f44549fee6d16a0888"),
"name" : "eosio.stake",
"balance" : 240020654.8,
"createdAt" : ISODate("2018-11-22T10:52:39.140Z")
}
{
"_id" : ObjectId("5bf684f64549fee6d16a2964"),
"name" : "eosio.faucet",
"balance" : 199999730,
"createdAt" : ISODate("2018-11-22T10:51:18.982Z")
}
...
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