storages::mongo::Pool Class Reference

Table of Contents

• Public Member Functions
• Friends
• Detailed Description
• Example usage:
• Member Function Documentation
• DropDatabase()

MongoDB client pool. More...

#include <userver/storages/mongo/pool.hpp>

Public Member Functions
bool	HasCollection (const std::string &name) const
	Checks whether a collection exists.
Collection	GetCollection (std::string name) const
	Returns a handle for the specified collection.
void	DropDatabase ()
void	Ping ()

Friends
void	DumpMetric (utils::statistics::Writer &writer, const Pool &pool)
	Writes pool statistics.

Detailed Description

MongoDB client pool.

Use constructor only for tests, in production the pool should be retrieved from the components via components::Mongo::GetPool() or components::MultiMongo::GetPool().

Example usage:

inline void SampleMongoPool(storages::mongo::Pool pool) {
  using formats::bson::MakeArray;
  using formats::bson::MakeDoc;
 
  auto in_coll = pool.GetCollection("aggregate_in");
 
  in_coll.InsertMany({
      formats::bson::MakeDoc("_id", 1, "x", 0),
      formats::bson::MakeDoc("_id", 2, "x", 1),
      formats::bson::MakeDoc("_id", 3, "x", 2),
  });
 
  auto cursor = in_coll.Aggregate(
      MakeArray(MakeDoc("$match", MakeDoc("_id", MakeDoc("$gte", 2))),
                MakeDoc("$addFields", MakeDoc("check", true)),
                MakeDoc("$out", "aggregate_out")),
      storages::mongo::options::ReadPreference::kSecondaryPreferred,
      storages::mongo::options::WriteConcern::kMajority);
  EXPECT_FALSE(cursor);
 
  auto out_coll = pool.GetCollection("aggregate_out");
  EXPECT_EQ(2, out_coll.CountApprox());
  for (const auto& doc : out_coll.Find({})) {
    EXPECT_EQ(doc["_id"].As<int>(), doc["x"].As<int>() + 1);
    EXPECT_TRUE(doc["check"].As<bool>());
  }
}

Definition at line 34 of file pool.hpp.

Member Function Documentation

DropDatabase()

void storages::mongo::Pool::DropDatabase

(

)

Drops the associated database if it exists. New modifications of collections will attempt to re-create the database automatically.

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The documentation for this class was generated from the following file:

• userver/storages/mongo/pool.hpp