145 lines
4.4 KiB
Elixir
145 lines
4.4 KiB
Elixir
defmodule OpentelemetryEcto do
|
|
@moduledoc """
|
|
Telemetry handler for creating OpenTelemetry Spans from Ecto query events. Any
|
|
relation preloads, which are executed in parallel in separate tasks, will be
|
|
linked to the span of the process that initiated the call. For example:
|
|
|
|
Tracer.with_span "parent span" do
|
|
Repo.all(Query.from(User, preload: [:posts, :comments]))
|
|
end
|
|
|
|
this will create a span called "parent span" with three child spans for each
|
|
query: users, posts, and comments.
|
|
|
|
> #### Note {: .neutral}
|
|
>
|
|
> Due to limitations with how Ecto emits its telemetry, nested preloads are not
|
|
> represented as nested spans within a trace.
|
|
"""
|
|
|
|
require OpenTelemetry.Tracer
|
|
|
|
@doc """
|
|
Attaches the OpentelemetryEcto handler to your repo events. This should be called
|
|
from your application behaviour on startup.
|
|
|
|
Example:
|
|
|
|
OpentelemetryEcto.setup([:blog, :repo])
|
|
|
|
You may also supply the following options in the second argument:
|
|
|
|
* `:time_unit` - a time unit used to convert the values of query phase
|
|
timings, defaults to `:microsecond`. See `System.convert_time_unit/3`
|
|
|
|
* `:span_prefix` - the first part of the span name, as a `String.t`,
|
|
defaults to the concatenation of the event name with periods, e.g.
|
|
`"blog.repo.query"`. This will always be followed with a colon and the
|
|
source (the table name for SQL adapters).
|
|
* `:additional_attributes` - additional attributes to include in the span. If there
|
|
are conflits with default provided attributes, the ones provided with
|
|
this config will have precedence.
|
|
"""
|
|
def setup(event_prefix, config \\ []) do
|
|
event = event_prefix ++ [:query]
|
|
:telemetry.attach({__MODULE__, event}, event, &__MODULE__.handle_event/4, config)
|
|
end
|
|
|
|
@doc false
|
|
def handle_event(
|
|
event,
|
|
measurements,
|
|
%{query: query, source: source, result: query_result, repo: repo, type: type},
|
|
config
|
|
) do
|
|
# Doing all this even if the span isn't sampled so the sampler
|
|
# could technically use the attributes to decide if it should sample or not
|
|
|
|
total_time = measurements.total_time
|
|
end_time = :opentelemetry.timestamp()
|
|
start_time = end_time - total_time
|
|
database = repo.config()[:database]
|
|
|
|
url =
|
|
case repo.config()[:url] do
|
|
nil ->
|
|
# TODO: add port
|
|
URI.to_string(%URI{scheme: "ecto", host: repo.config()[:hostname]})
|
|
|
|
url ->
|
|
url
|
|
end
|
|
|
|
span_name =
|
|
case Keyword.fetch(config, :span_prefix) do
|
|
{:ok, prefix} -> prefix
|
|
:error -> Enum.join(event, ".")
|
|
end <> if source != nil, do: ":#{source}", else: ""
|
|
|
|
time_unit = Keyword.get(config, :time_unit, :microsecond)
|
|
additional_attributes = Keyword.get(config, :additional_attributes, %{})
|
|
|
|
db_type =
|
|
case type do
|
|
:ecto_sql_query -> :sql
|
|
_ -> type
|
|
end
|
|
|
|
# TODO: need connection information to complete the required attributes
|
|
# net.peer.name or net.peer.ip and net.peer.port
|
|
base_attributes = %{
|
|
"db.type": db_type,
|
|
"db.statement": query,
|
|
source: source,
|
|
"db.instance": database,
|
|
"db.url": url,
|
|
"total_time_#{time_unit}s": System.convert_time_unit(total_time, :native, time_unit)
|
|
}
|
|
|
|
attributes =
|
|
measurements
|
|
|> Enum.reduce(%{}, fn
|
|
{k, v}, acc when not is_nil(v) and k in [:decode_time, :query_time, :queue_time, :idle_time] ->
|
|
Map.put(acc, String.to_atom("#{k}_#{time_unit}s"), System.convert_time_unit(v, :native, time_unit))
|
|
|
|
_, acc ->
|
|
acc
|
|
end)
|
|
|> Map.merge(base_attributes)
|
|
|> Map.merge(additional_attributes)
|
|
|
|
parent_context = OpentelemetryProcessPropagator.fetch_parent_ctx(1, :"$callers")
|
|
|
|
if parent_context != :undefined do
|
|
OpenTelemetry.Ctx.attach(parent_context)
|
|
end
|
|
|
|
s =
|
|
OpenTelemetry.Tracer.start_span(span_name, %{
|
|
start_time: start_time,
|
|
attributes: attributes,
|
|
kind: :client
|
|
})
|
|
|
|
case query_result do
|
|
{:error, error} ->
|
|
OpenTelemetry.Span.set_status(s, OpenTelemetry.status(:error, format_error(error)))
|
|
|
|
{:ok, _} ->
|
|
:ok
|
|
end
|
|
|
|
OpenTelemetry.Span.end_span(s)
|
|
|
|
if parent_context != :undefined do
|
|
OpenTelemetry.Ctx.detach(parent_context)
|
|
end
|
|
end
|
|
|
|
defp format_error(%{__exception__: true} = exception) do
|
|
Exception.message(exception)
|
|
end
|
|
|
|
defp format_error(_), do: ""
|
|
end
|