Refactor: improve code quality and worker flow

Backend/db/migrations/000005_background_jobs.sql

@@ -0,0 +1,64 @@
+-- +goose Up
+
+CREATE TYPE bootstrap_materialization_status AS ENUM ('not_started', 'pending', 'running', 'succeeded', 'failed');
+CREATE TYPE background_job_status AS ENUM ('pending', 'running', 'succeeded', 'failed');
+
+ALTER TABLE installations
+  ADD COLUMN IF NOT EXISTS materialization_status bootstrap_materialization_status NOT NULL DEFAULT 'not_started',
+  ADD COLUMN IF NOT EXISTS materialization_error TEXT,
+  ADD COLUMN IF NOT EXISTS materialization_requested_at TIMESTAMPTZ,
+  ADD COLUMN IF NOT EXISTS materialization_started_at TIMESTAMPTZ,
+  ADD COLUMN IF NOT EXISTS materialization_finished_at TIMESTAMPTZ;
+
+UPDATE installations
+SET
+  materialization_status = CASE
+    WHEN is_bootstrapped THEN 'succeeded'::bootstrap_materialization_status
+    ELSE 'not_started'::bootstrap_materialization_status
+  END,
+  materialization_error = NULL,
+  materialization_requested_at = CASE
+    WHEN is_bootstrapped THEN COALESCE(bootstrapped_at, created_at, NOW())
+    ELSE NULL
+  END,
+  materialization_started_at = CASE
+    WHEN is_bootstrapped THEN COALESCE(bootstrapped_at, created_at, NOW())
+    ELSE NULL
+  END,
+  materialization_finished_at = CASE
+    WHEN is_bootstrapped THEN COALESCE(bootstrapped_at, created_at, NOW())
+    ELSE NULL
+  END
+WHERE materialization_status = 'not_started'::bootstrap_materialization_status;
+
+CREATE TABLE IF NOT EXISTS background_jobs (
+  id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
+  kind TEXT NOT NULL,
+  status background_job_status NOT NULL DEFAULT 'pending',
+  payload JSONB NOT NULL DEFAULT '{}'::jsonb,
+  attempts INTEGER NOT NULL DEFAULT 0,
+  max_attempts INTEGER NOT NULL DEFAULT 1,
+  available_at TIMESTAMPTZ NOT NULL DEFAULT NOW(),
+  started_at TIMESTAMPTZ,
+  finished_at TIMESTAMPTZ,
+  last_error TEXT,
+  created_at TIMESTAMPTZ NOT NULL DEFAULT NOW(),
+  updated_at TIMESTAMPTZ NOT NULL DEFAULT NOW()
+);
+
+CREATE INDEX IF NOT EXISTS idx_background_jobs_claim ON background_jobs (status, available_at, created_at);
+
+-- +goose Down
+
+DROP INDEX IF EXISTS idx_background_jobs_claim;
+DROP TABLE IF EXISTS background_jobs;
+
+ALTER TABLE installations
+  DROP COLUMN IF EXISTS materialization_finished_at,
+  DROP COLUMN IF EXISTS materialization_started_at,
+  DROP COLUMN IF EXISTS materialization_requested_at,
+  DROP COLUMN IF EXISTS materialization_error,
+  DROP COLUMN IF EXISTS materialization_status;
+
+DROP TYPE IF EXISTS background_job_status;
+DROP TYPE IF EXISTS bootstrap_materialization_status;