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ex_money
0.1.6
6.1.1
6.1.0
6.0.0
6.0.0-rc.0
5.24.2
5.24.1
5.24.0
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5.10.0
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5.8.0
5.7.4
5.7.3
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5.4.0
5.4.0-rc.0
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5.3.1
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5.2.0
5.1.0
5.0.2
5.0.1
5.0.0
retired
4.4.3
4.4.2
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4.4.1
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3.2.2
3.2.1
3.2.0
3.1.0
3.0.0
2.12.2
2.12.1
retired
2.12.0
retired
2.11.0
2.10.0
2.9.1
2.9.0
2.8.0
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2.7.1
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2.1.0-rc.1
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2.1.0-rc.0
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2.0.3
2.0.2
2.0.1
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retired
0.9.0
retired
0.8.5
retired
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retired
0.8.3
retired
0.8.2
retired
0.8.1
retired
0.8.0
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0.6.2
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0.6.1
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0.6.0
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0.5.3
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0.5.2
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0.5.1
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0.5.0
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0.4.3
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0.4.0
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0.3.0
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0.2.0
retired
0.1.7
retired
0.1.6
retired
0.1.5
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0.1.4
retired
0.1.3
retired
0.1.2
retired
0.1.1
retired
0.1.0
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0.0.16
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0.0.15
retired
0.0.14
retired
0.0.13
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0.0.12
retired
0.0.11
retired
0.0.10
retired
0.0.9
retired
0.0.7
retired
0.0.6
retired
0.0.5
retired
0.0.4
retired
0.0.3
retired
0.0.2
retired
Money functions for operations on and localization of a money data type with support for ISO 4217 currencies and ISO 24165 digial tokens (crypto currencies).
Retired package: Deprecated
Current section
Files
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Files
lib/money/exchange_rates/exchange_rates_retriever.ex
defmodule Money.ExchangeRates.Retriever do
@moduledoc """
Implements a `GenServer` to retrieve exchange rates from
a configured retrieveal module on a periodic basis. By default exchange
rates are retrieved from [Open Exchange Rates](http://openexchangerates.org).
Retrieved data is stored in an `:ets` table.
By default the period of execution is 5 minutes (360_000 microseconds). The
period of retrieval is configured in `config.exs` or the appropriate
environment configuration. For example:
config :ex_money,
open_exchange_rates_app_id: "app_id_string",
open_exchange_rates_retrieve_every: 360_000
"""
use GenServer
require Logger
def start_link(name, config) do
GenServer.start_link(__MODULE__, config, name: name)
end
def init(config) do
log(config, :info, "Starting exchange rate retrieval service")
log(config, :info, "Rates will be retrieved every #{div(config.retrieve_every, 1000)} seconds.")
initialize_ets_table()
retrieve_rates(config)
schedule_work(config.retrieve_every)
{:ok, config}
end
def handle_info(:latest, config) do
retrieve_rates(config)
schedule_work(config.retrieve_every)
{:noreply, config}
end
def retrieve_rates(%{callback_module: callback_module} = config) do
case Money.ExchangeRates.get_latest_rates() do
{:ok, rates} ->
retrieved_at = DateTime.utc_now
store_rates(rates, retrieved_at)
apply(callback_module, :rates_retrieved, [rates, retrieved_at])
log(config, :success, "Retrieved exchange rates successfully")
{:ok, rates}
{:error, reason} ->
log(config, :failure, "Error retrieving exchange rates: #{inspect reason}")
{:error, reason}
end
end
defp schedule_work(delay_ms) do
Process.send_after(self(), :latest, delay_ms)
end
defp initialize_ets_table do
:ets.new(:exchange_rates, [:named_table, read_concurrency: true])
end
defp store_rates(rates, retrieved_at) do
:ets.insert(:exchange_rates, {:rates, rates})
:ets.insert(:exchange_rates, {:last_updated, retrieved_at})
end
defp log(%{log_levels: log_levels}, key, message) do
case Map.get(log_levels, key) do
nil ->
nil
log_level ->
Logger.log(log_level, message)
end
end
end