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https://github.com/benbusby/farside.git
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1fb9051ae1
Rather than enforcing a 200 status code, the instance query is deemed a success if the status code is <400. Various services return 200-399 status codes that don't necessarily indicate an error, but may have to do with how the instance was configured.
110 lines
2.8 KiB
Elixir
110 lines
2.8 KiB
Elixir
defmodule Farside.Instances do
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@fallback_suffix Application.fetch_env!(:farside, :fallback_suffix)
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@update_file Application.fetch_env!(:farside, :update_file)
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@services_json Application.fetch_env!(:farside, :services_json)
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@service_prefix Application.fetch_env!(:farside, :service_prefix)
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@headers Application.fetch_env!(:farside, :headers)
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@queries Application.fetch_env!(:farside, :queries)
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@debug_header "======== "
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@debug_spacer " "
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def sync() do
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File.rename(@update_file, "#{@update_file}-prev")
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update()
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# Add UTC time of last update
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Redix.command(:redix, [
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"SET",
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"last_updated",
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Calendar.strftime(DateTime.utc_now(), "%c")
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])
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end
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def request(url) do
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cond do
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System.get_env("FARSIDE_TEST") ->
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:good
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true ->
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HTTPoison.get(url, @headers)
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|> then(&elem(&1, 1))
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|> Map.get(:status_code)
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|> case do
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n when n < 400 ->
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IO.puts("#{@debug_spacer}✓ [#{n}]")
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:good
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n ->
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IO.puts("#{@debug_spacer}x [#{(n && n) || "error"}]")
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:bad
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end
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end
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end
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def update() do
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{:ok, file} = File.read(@services_json)
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{:ok, json} = Poison.decode(file, as: [%Service{}])
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# Loop through all instances and check each for availability
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for service <- json do
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IO.puts("#{@debug_header}#{service.type}")
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result =
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Enum.filter(service.instances, fn instance_url ->
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request_url =
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instance_url <>
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EEx.eval_string(
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service.test_url,
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query: Enum.random(@queries)
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)
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IO.puts("#{@debug_spacer}#{request_url}")
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request(request_url) == :good
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end)
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add_to_redis(service, result)
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log_results(service.type, result)
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end
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end
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def add_to_redis(service, instances) do
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# Remove previous list of instances
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Redix.command(:redix, [
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"DEL",
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"#{@service_prefix}#{service.type}"
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])
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# Update with new list of available instances
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Redix.command(
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:redix,
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[
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"LPUSH",
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"#{@service_prefix}#{service.type}"
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] ++ instances
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)
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# Set fallback to one of the available instances,
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# or the default instance if all are "down"
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if Enum.count(instances) > 0 do
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Redix.command(:redix, [
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"SET",
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"#{service.type}#{@fallback_suffix}",
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Enum.random(instances)
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])
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else
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Redix.command(:redix, [
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"SET",
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"#{service.type}#{@fallback_suffix}",
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service.fallback
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])
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end
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end
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def log_results(service_name, results) do
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{:ok, file} = File.open(@update_file, [:append, {:delayed_write, 100, 20}])
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IO.write(file, "#{service_name}: #{inspect(results)}\n")
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File.close(file)
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end
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end
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