ADR-006: Installer on hc client call

• Status: Accepted
• Date: 2026-08-28
• Source: #1, issue description, section “Decisions (ADRs, continuing the numbering of the May design doc)”

Context

From the state of the repository recorded in #1 when the decision was taken (verified 2026-08-28):

The hApp installer in modules/holochain-edgenode.nix calls hc app install, hc app enable and hc app attach-interface. None exist. In the pinned holonix (rev d49ebd5e7a, Holochain 0.7.0-dev.24), hc app has only init | pack | unpack | schema. The admin calls live under hc client call --port <admin-port> install-app | enable-app | add-app-ws | list-apps | dump-network-stats | dump-network-metrics.

Decision

The hApp installer service uses hc client call --port ${adminPort} install-app, enable-app, add-app-ws, verified against the real binary in a NixOS VM test. The May design’s Node.js fallback (§4.5) is dropped.

The May design and its §4.5 are not in this repository. §4.5 was the Node.js fallback (a helper using @holochain/client) of the May design’s installer decision, ADR-004, which is not published here (see the index).

Consequences

The record states no consequences beyond the decision itself.

Later record

• On the 0.6 line, which ADR-007 as amended added, the same admin calls run under hc sandbox call --running <adminPort>: the 0.6.3 hc has no client subcommand. This is recorded in #16 and re-derived in its review, and it is what modules/holochain-edgenode.nix does on main.