be7f584010
Dynamically supervise a GRPC connection and keep it alive for a while, using a timeout to kill the process on inactivity. The Connection GenServer keeps the connection alive, while listening to a health stream from the GRPC endpoint, notifying any subscribed listeners about changes to health. This health is then propagated to the main servers page. Also create a looping get_sys_info which retrieves some basic system information.
66 lines
1.7 KiB
Elixir
66 lines
1.7 KiB
Elixir
defmodule Prymn.Agents.Health do
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@doc """
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The Health struct keeps simple health information of
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whether or not the target host machine is up to date, has any tasks running,
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its resources are getting depleted, or if it's unable be reached.
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"""
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defstruct [:version, message: "Unknown"]
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alias PrymnProto.Prymn.HealthResponse
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@type t :: %{
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version: String.t(),
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message: String.t()
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}
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@doc false
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def start() do
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:ets.new(__MODULE__, [:set, :public, :named_table, read_concurrency: true])
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end
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@doc false
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def subscribe(host_address) do
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Phoenix.PubSub.subscribe(Prymn.PubSub, "health:#{host_address}")
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end
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@doc false
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def update(health, host_address) do
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:ets.insert(__MODULE__, {host_address, health})
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Phoenix.PubSub.broadcast!(Prymn.PubSub, "health:#{host_address}", {host_address, health})
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end
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@doc false
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def lookup(host_address) do
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case :ets.lookup(__MODULE__, host_address) do
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[{^host_address, value}] -> value
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[] -> nil
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end
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end
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@doc false
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def new_from_proto(proto_health) do
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case proto_health do
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%HealthResponse{} = health ->
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from_health(health)
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%GRPC.RPCError{message: ":stream_error: :closed"} ->
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%__MODULE__{message: "Disconnected"}
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%GRPC.RPCError{} = error ->
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require Logger
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Logger.error("unhandled GRPC error received in Health module: #{inspect(error)}")
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%__MODULE__{message: "Error retrieving server status"}
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end
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end
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defp from_health(%HealthResponse{system: system, version: version}) do
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case system.status do
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"normal" ->
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%__MODULE__{message: "Connected", version: version}
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status ->
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%__MODULE__{message: status, version: version}
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end
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end
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end
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