mix malachi.ring (malachi v0.22.7)

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Prints the cluster's durable ring: the vnode topology of record, read from a running Malachi node over Erlang distribution (RPC).

mix malachi.ring --show

The ring outranks MALACHI_LOG_VNODES at boot, because a ring grown by re-sharding no longer matches the environment's even geometry and honouring the environment would orphan the migrated metadata. So when a node logs that it ignored the environment, this is the command that says what it used instead: the recorded version, the vnodes and their tokens, and where each one's ra cluster lives.

A pending line means a vnode split was interrupted; the node holding the lease carries it to completion, and it survives a full-cluster restart because the intent is part of the recorded ring.

Options:

  • --show: print the ring (the default, and currently the only action)
  • --node: the target node (default $MALACHI_NODE or malachi@127.0.0.1)
  • --cookie: the Erlang cookie (default $RELEASE_COOKIE, else ~/.erlang.cookie)

The target node must be named and running a clustered control plane; an unclustered node has no ring store to read.

Summary

Functions

execute(arg1, node, call)

The testable core: reads the ring store on node through call (a (module, fun, args -> {:ok, value} | {:error, reason}) seam that in production is an RPC to the target node) and renders it. Returns {:ok, text} / {:error, message} for the caller to print.

Functions

execute(arg1, node, call)

@spec execute([String.t()], node(), (module(), atom(), list() ->
                                 {:ok, term()} | {:error, term()})) ::
  {:ok, String.t()} | {:error, String.t()}

The testable core: reads the ring store on node through call (a (module, fun, args -> {:ok, value} | {:error, reason}) seam that in production is an RPC to the target node) and renders it. Returns {:ok, text} / {:error, message} for the caller to print.

Stray positional arguments return usage rather than being ignored.