Learn in depth about Mongo driver implementation.

Mongo

Mongo driver uses mongodb_driver client package to talk to database. It uses UnorderedBulk and find operations for interacting with database.

Configuration

You can configure driver directly using mongodb_driver package.

{:ok, connection} = Mongo.start_link(url: "mongodb://mongo:27017/stats")
driver = Trifle.Stats.Driver.Mongo.new(connection)

config = Trifle.Stats.Configuration.configure(driver, ...)

Setup

Mongo driver requires trifle_stats collection to be present. You can override collection_name when creating an instance of a driver and pass your own as a second argument.

You can create collection and index on your own or simply call setup! function that does this for you. It creates a collection and adds an unique index on a key attribute.

Below is a setup and configuration for a custom database and a collection name.

{:ok, connection} = Mongo.start_link(url: "mongodb://mongo:27017/stats")
Trifle.Stats.Driver.Mongo.setup(connection, 'my_stats')

driver = Trifle.Stats.Driver.Mongo.new(connection, 'my_stats')

Driver

Here is an actual example from iex how to create a driver.

iex(1)> {:ok, connection} = Mongo.start_link(url: "mongodb://mongo:27017/stats")
{:ok, #PID<0.850.0>}
iex(2)> driver = Trifle.Stats.Driver.Mongo.new(connection)
%Trifle.Stats.Driver.Mongo{
  connection: #PID<0.850.0>,
  collection_name: "trifle_stats",
  separator: "::",
  write_concern: 1
}

Optional configuration

You can pass collection_name, separator as well as write_concern as following arguments. Separator is used to join values in a list into single identifiable key. Modifying write concern may speed up your stats as you may wanna skip write confirmation for heavy load apps.

iex(1)> {:ok, connection} = Mongo.start_link(url: "mongodb://mongo:27017/stats")
{:ok, #PID<0.879.0>}
iex(2)> driver = Trifle.Stats.Driver.Mongo.new(connection, "test_stats", "--", write_concern: 0)
%Trifle.Stats.Driver.Mongo{
  connection: #PID<0.879.0>,
  collection_name: "test_stats",
  separator: "--",
  write_concern: [write_concern: 0]
}

Interaction

Once you create instance of a driver, you can use it to set, inc or get your data.

iex(3)> Trifle.Stats.Driver.Mongo.get([['test', 'now']], driver)
[%{}]

iex(4)> Trifle.Stats.Driver.Mongo.inc([['test', 'now']], %{"count" => 1, "success" => 1, "error" => 0}, driver)
%Mongo.BulkWriteResult{
  acknowledged: true,
  matched_count: 0,
  modified_count: 0,
  inserted_count: 0,
  deleted_count: 0,
  upserted_count: 1,
  inserted_ids: [],
  upserted_ids: [#BSON.ObjectId<64964ec5ab39049bf04982d1>],
  errors: []
}

iex(5)> Trifle.Stats.Driver.Mongo.inc([['test', 'now']], %{"count" => 1, "success" => 0, "error" => 1, "account" => %{ "count" => 1 }}, driver)
%Mongo.BulkWriteResult{
  acknowledged: true,
  matched_count: 1,
  modified_count: 1,
  inserted_count: 0,
  deleted_count: 0,
  upserted_count: 0,
  inserted_ids: [],
  upserted_ids: [],
  errors: []
}

iex(6)> Trifle.Stats.Driver.Mongo.get([['test', 'now']], driver)
[%{"account" => %{"count" => 1}, "count" => 2, "error" => 1, "success" => 1}]

Performance

All good here! set and inc are executed in one query and each key in keys is executed as a one bulk write operation. get fetches all keys in a single query.