Create a scheduler/executor implementation for workspace auto on/off.

• Add table workspace_lifecycle_job

  CREATE TYPE workspace_lifecycle_operation AS ENUM ('stop', 'start')
  CREATE TABLE workspace_lifecycle_job (
    id uuid NOT NULL, -- unique job ID
    created_at timestamp with time zone NOT NULL, -- when the job was created
    updated_at timestamp with time zone NOT NULL, -- when the job was last updated
    started_at timestamp with time zone, -- when the job was started, null means it's pending
    cancelled_at timestamp with time zone, -- when the job was cancelled, null means it hasn't been cancelled
    completed_at timestamp with time zone, -- when the job was completed, null means it hasn't finished yet 
    error text, -- any errors encountered from the job
    workspace_id uuid NOT NULL, -- target workspace
    operation workspace_lifecycle_operation NOT NULL, -- start or stop
    deadline timestamp with time zone NOT NULL, --  when the job is to be executed
    PRIMARY KEY (id)
  )

• Add table workspace_lifecycle_job_logs

  CREATE TABLE workspace_lifecycle_job_logs (
      id uuid NOT NULL, -- unique row id
      job_id uuid NOT NULL, -- uuid of the workspace lifecycle job that created it
      created_at timestamp with time zone NOT NULL, -- when the logs were created
      level log_level NOT NULL, -- level of the log
      output character varying(1024) NOT NULL -- content of the log
  );

• Add required methods to querier.go:

  • AcquireWorkspaceLifecycleJob acquires the lock for a single workspace lifecycle job that isn't started, completed, or cancelled using SKIP LOCKED.
  • InsertWorkspaceLifecycleJob inserts a new row into the workspace_lifecycle_job table
  • InsertWorkspaceLifecycleJobLogs inserts a new row into the workspace_lifecycle_job_logs table
  • UpdateWorkspaceLifecycleJobByID updates a row of the workspace_lifecycle_job_logs table
  • UpdateWorkspaceLifecycleJobWithCancelByID marks a row of the workspace_lifecycle_job table as cancelled
  • UpdateWorkspaceLifecycleJobWithCompleteByID marks a row of the workspace_lifecycle_job table as completed

• Create a WorkspaceLifecycleJobScheduler that schedules starting and stopping workspaces at their scheduled start time/stop time

  • A goroutine tied to the application lifecycle will iterate over all workspaces periodically.
  • If a workspace is running and has a defined auto-stop time, if there is no corresponding auto-stop job pending then create said job.
  • If a workspace is stopped and has a defined auto-start time, if there is no corresponding auto-start job pending then create said job.
  • If an auto-start job is pending for a workspace that has no defined auto-start time, mark the job as cancelled.
  • If an auto-stop job is pending for a workspace that has no defined auto-stop time, mark the job as cancelled.

• Create an WorkspaceLifecycleJobExecutor that executes jobs from workspace_lifecycle_job:

  • A goroutine tied to the application lifecycle will continuously wait for a pending workspace lifecycle job that has not been claimed.
  • When an unclaimed job is found:
    • Mark the job as claimed (setting started_at and updated_at)
    • Triggers the workspace stop/start unless the workspace is already in the desired state (stopped for auto-stop, running for auto-start)
    • Mark the job as completed