Hey,
I got a list of structs which I need to convert to a map (or similar useful data structure) that I can then further use to create some Prometheus metrics.
Here is what I got. The code is quite dirty in my opinion and maybe there is a smarter way to do it. I wrote it last night at 1am just to get it done, don’t judge me
Input data:
trackers = [
%{
pause: true,
pause_timeout_in_ms: 72276156,
position: %{"lat" => 11, "lng" => 1},
response: nil,
timeout_in_ms: 309722,
user_id: "5cb6fb2c2071c963d21c517f"
},
%{
pause: false,
pause_timeout_in_ms: false,
position: %{"lat" => 11, "lng" => 1},
response: %{
"status" => "ok",
"vehicle_position" => %{"vehicle" => %{"tracking" => nil}}
},
timeout_in_ms: 1747683,
user_id: "5cb6fb2d2071c963d21c5180"
}
]
Then I do the following:
trackers
|> Enum.map(
fn x ->
state = case x[:pause] do
true -> "paused"
false -> "active"
end
health = case x[:response] do
nil -> "unhealthy"
_ -> "healthy"
end
%{state: state, health: health}
end
)
|> Enum.reduce(
%{
"active" => %{
"healthy" => 0,
"unhealthy" => 0
},
"paused" => %{
"healthy" => 0,
"unhealthy" => 0
}
},
fn (x, acc) ->
put_in(acc[x[:state]][x[:health]], get_in(acc, [x[:state], x[:health]]) + 1)
end
)
(Ignore the inline functions, gonna clean it up after the implementation is set)
Which gives me the following output:
%{
"active" => %{"healthy" => 1, "unhealthy" => 0},
"paused" => %{"healthy" => 0, "unhealthy" => 1}
}
Which I then use the following way:
series = for {state, health} <- extract_labeled_data(trackers), # extract_labeled_data is the cove above
{health, value} <- health do
{[state: state, health: health], value}
end
Prometheus.Model.gauge_metrics(series)
To generate Prometheus metrics like:
app_gateway_tracking_sessions_count{state="active",health="healthy"} 1
app_gateway_tracking_sessions_count{state="active",health="unhealthy"} 0
app_gateway_tracking_sessions_count{state="paused",health="healthy"} 0
app_gateway_tracking_sessions_count{state="paused",health="unhealthy"} 1
I am sure there are some things that can be improved to get from the input data to the final metrics.