Initial commit

elixir/log-level/lib/log_level.ex

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+defmodule LogLevel do
+  @doc """
+  Log code    Log label      Supported in legacy apps?
+  0           trace          no
+  1           debug          yes
+  2           info           yes
+  3           warning	       yes
+  4           error          yes
+  5           fatal          no
+  other       unknown        -
+
+  case {level, legacy?} do
+    {0, false} -> :trace
+    {1, _} -> :debug
+    {2, _} -> :info
+    {3, _} -> :warning
+    {4, _} -> :error
+    {5, false} -> :fatal
+    _ -> :unknown
+  end
+
+  """
+  def to_label(level, legacy?) do
+    cond do
+      level == 0 and not legacy? -> :trace
+      level == 1 -> :debug
+      level == 2 -> :info
+      level == 3 -> :warning
+      level == 4 -> :error
+      level == 5 and not legacy? -> :fatal
+      true -> :unknown
+    end
+  end
+
+  @doc """
+  If the log label is error or fatal, send the alert to the ops team. If you receive a log with an unknown label from a legacy system, send the alert to the dev1 team, other unknown labels should be sent to the dev2 team. All other log labels can be safely ignored by returning false.
+  """
+  def alert_recipient(level, legacy?) do
+    label = to_label(level, legacy?)
+    cond do
+      label in [:error, :fatal] -> :ops
+      label == :unknown and legacy? -> :dev1
+      label == :unknown -> :dev2
+      true -> false
+    end
+  end
+end