hc run ... doesn't allocate a temporary work directory; all agents share one

[pjkundert]

Starting multiple agents via hc run ... causes communications failure between the agents, because some communications details are persisted to the directory, and both agents end up using the same persistence directory and using the same communications details.

When running an agent via hc run ..., there are 2 major use cases:

1. Starting the agent for testing, with intent to discard the resultant source chain and other data
2. Persisting the source chain and other data between hc runs ... invocations

The default, without specifying options to the contrary, should be to create a temporary directory that contains the source chain and data, which is discarded at the end of execution.

A --persist=<directory> option should be added, to allow the explicit provision of a directory to persist source chain and other necessary data into.

[pjkundert]

Here's an example of how to invoke hc in such a way that you can run multiple instances; where each instance gets a separate persistence directory: https://github.com/mjbrisebois/holofuel-app/blob/master/Makefile

[pjkundert]

It appears that the root cause of the problem is that hc uses one NetworkConfig::n3h_persistence_path (see conductor_api/src/config.rs) for all of its data -- except that some of that data is per-agent in nature. Since hc run can be started representing multiple different agents (via the HC_AGENT" environment variable), the per-agent data should use the n3h_persistence_path`, but place the per-agent data in a per-agent sub-directory.

The only option now available to obtain a working hc run with multiple different HC_AGENT=AgentN... configurations, is to also always specify a unique HC_N3H_WORK_DIR=$( mktemp -d ). If you attempt to use hc run with different HC_AGENT=... configurations, you will always experience failures.

[pjkundert]

Work-in-progress for a temporary (until n3h correctly separates per-agent assets) fix in holochain-rust in branch feature-hc-per-agent-tempdir

[jamesray1]

I think this is still an issue but I think some of the details are out of date here.

[P2-asap]