Milvex.Migration.CLI (milvex v0.14.0)

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Layered, halt-free entry point for mix milvex.migrate.

Parses argv, validates flags, resolves modules / prefixes, computes plans via Milvex.Migration.Plan.diff/4, optionally applies them via Milvex.Migration.Runner.apply/2, and renders output via Milvex.Migration.Reporter.render/2.

Returns {exit_code, iodata}. Never calls System.halt/1. The Mix task wraps this and is responsible for halting.

Exit code priority hierarchy

When multiple conditions could apply, the higher number wins (1 > 2 > 4 > 3 > 0):

  • 0 — clean
  • 1 — configuration / argv error
  • 2 — at least one impossible op present (plan mode); apply blocked by impossible
  • 3 — destructive ops present without --allow-drop (plan mode); skipped by runner (apply mode)
  • 4 — at least one RPC failure during apply; describe_collection error during plan computation

Dependency injection

Callers may pass fetch_config_fn and connect_fn to override the defaults. This is used in tests to avoid touching real Application env or live processes.

Summary

Types

connect_fn()
fetch_config_fn()
opts()

Functions

run(argv, fetch_config_fn \\ &Application.get_env/2, connect_fn \\ &default_connect/1)

Parses argv, resolves the target modules/prefixes and connection, computes migration plans, and runs them in either --plan or --apply mode.

Types

connect_fn()

@type connect_fn() :: (atom() | nil -> {:ok, GenServer.server()} | {:error, term()})

fetch_config_fn()

@type fetch_config_fn() :: (atom(), atom() -> term())

opts()

@type opts() :: %{
  mode: :plan | :apply,
  allow_drop: boolean(),
  manage_load: boolean(),
  modules: [String.t()],
  prefixes: [String.t()],
  format: :text | :json,
  connection: String.t() | nil
}

Functions

run(argv, fetch_config_fn \\ &Application.get_env/2, connect_fn \\ &default_connect/1)

@spec run([String.t()], fetch_config_fn(), connect_fn()) :: {0..4, iodata()}

Parses argv, resolves the target modules/prefixes and connection, computes migration plans, and runs them in either --plan or --apply mode.

Returns {exit_code, output} where output is iodata ready to write to stdout. fetch_config_fn and connect_fn are injectable for testing.