Giuliano Silvestro
b9fc4f9cf3
The most load-bearing write workflow — droplet provisioning is the spine
of phase 4a deployment onboarding.
DigitalOcean.Client: create_droplet, get_droplet, list_droplets_by_tag,
destroy_droplet. list_paginated/3 now threads caller-supplied params
(opts[:params]) through pagination so tag-filtered listing works.
Four droplet saga steps:
- CreateDroplet — POST a droplet, tagged arcadia-saga-<saga8> +
managed-by-arcadia-cloud. Idempotency: re-run checks context for
droplet_id, then queries DO by the saga tag, so a crash between POST
and context-save adopts the existing droplet. compensate destroys it.
- WaitDropletActive — polls get_droplet until status "active" (96x5s);
records the public IP. No compensation (waiting has no side effect).
- RegisterDroplet — fetches the droplet, upserts it into cloud_resources
(inventory consistent immediately, not at next 15-min sync) and writes
cloud_provisioned desired-state {size_slug, region, image}. compensate
removes the DB rows (the droplet itself is destroyed by CreateDroplet's
compensate).
- DestroyDroplet — DELETE the droplet + mark its cloud_resources row
deleted. Terminal/irreversible: compensate is a logged noop, per the
saga design destroy-class steps don't roll back.
Provisioning helpers:
- provision_droplet/1 — [CreateDroplet, WaitDropletActive, RegisterDroplet]
- destroy_droplet/2 — [DestroyDroplet]
Live smoke verified end-to-end (full create + destroy on a real
s-1vcpu-512mb-10gb droplet in syd1):
- provision saga completed: droplet 572017320 created, reached active
with public IP, registered into cloud_resources (status=active) +
cloud_provisioned (spec recorded).
- destroy saga completed: cloud_resources row marked deleted; droplet
confirmed 404 on DO afterward. Account back to its original 5
droplets, zero leftover, ~1 cent total cost.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
60 lines
1.7 KiB
Elixir
60 lines
1.7 KiB
Elixir
defmodule ArcadiaCloud.Provisioning.Steps.WaitDropletActive do
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@moduledoc """
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Polls a droplet (created by a prior CreateDroplet step) until its
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status is "active". Reads `droplet_id` from saga context.
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No compensation — waiting has no side effect to undo. If the saga
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rolls back, the prior CreateDroplet step's compensate destroys the
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droplet regardless of whether it ever reached active.
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"""
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@behaviour ArcadiaCloud.Provisioning.Step
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alias ArcadiaCloud.DigitalOcean.Client
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alias ArcadiaCloud.Provisioning.SagaState
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@poll_interval_ms 5_000
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@poll_max_attempts 96
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@impl true
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def name, do: "wait_droplet_active"
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@impl true
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def execute(state) do
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case SagaState.get_output(state, :droplet_id) do
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nil -> {:error, :no_droplet_id_in_context}
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droplet_id -> poll(state, droplet_id, 1)
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end
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end
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defp poll(_state, _droplet_id, attempt) when attempt > @poll_max_attempts do
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{:error, :droplet_active_timeout}
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end
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defp poll(state, droplet_id, attempt) do
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case Client.get_droplet(droplet_id) do
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{:ok, %{"status" => "active"} = droplet} ->
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public_ip = extract_public_ip(droplet)
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{:ok, SagaState.put_output(state, :droplet_public_ip, public_ip)}
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{:ok, %{"status" => status}} when status in ["new", "off"] ->
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Process.sleep(@poll_interval_ms)
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poll(state, droplet_id, attempt + 1)
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{:ok, %{"status" => other}} ->
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{:error, {:unexpected_droplet_status, other}}
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{:error, reason} ->
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{:error, reason}
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end
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end
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defp extract_public_ip(droplet) do
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droplet
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|> get_in(["networks", "v4"])
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|> List.wrap()
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|> Enum.find(%{}, &(&1["type"] == "public"))
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|> Map.get("ip_address")
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end
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end
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