feat(mcp): SQLite-backed MCP server config storage + boot merge (#6021)#6106
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Bounded storage slice of #6021. Adds migration v43 (mcp_server_configs table), an McpConfigStore CRUD layer in librefang-memory over the shared r2d2 pool, and a boot-time merge that overlays DB rows over the file-backed [[mcp_servers]] by name (DB overrides file; empty table is a byte-for-byte no-op so file-only setups are unchanged). Lets config.toml be a read-only ConfigMap on K8s. API/CLI write-path, hot-reload, and a file->DB import are scoped follow-ups.
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CHANGELOG bullet for #6021 was 6 sentences on a single line; split to one sentence per line per the prose-wrapping rule. Multi-line comment blocks in boot.rs (9 lines), migration.rs (6 lines), and mcp_config_store.rs (module doc 20 lines + four multi-paragraph method docs) compressed to one short line each per project rule. No behaviour change.
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Pushed one style commit (5939a56): CHANGELOG bullet split to one sentence per line, and multi-paragraph comment blocks in boot.rs, migration.rs, and mcp_config_store.rs compressed to one line each per project rules.
One finding left as a review comment: the boot-merge loop in boot.rs has no direct test (see inline note).
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…ime_store (#6113) (#6115) * feat(mcp): persist /api/mcp/servers writes to a DB store via mcp_runtime_store #6106 added the SQLite mcp_server_configs store and a boot-time merge, but the API write-path (POST/PUT/DELETE /api/mcp/servers, the taint patch) and the read-path still only saw config.toml. A DB-managed MCP server was therefore invisible to the API and could not be added at all when config.toml was a read-only Kubernetes ConfigMap — the #6021 motivation. Add a `mcp_runtime_store` knob (default `file`, byte-for-byte the prior behaviour; `db` routes writes to the store). The boot overlay and reload_mcp_servers now share one McpConfigStore::merge_over helper, so the hot-reload path no longer drops DB-backed servers the boot merge had applied. The handlers read the effective (file + DB) set, so DB-backed servers are listed, fetched, updated, and deleted like file-backed ones and take effect without a restart. Tests: McpConfigStore::merge_over unit tests and the mcp_runtime_store_db_test API integration suite. Closes #6113. * test(config-overlay): exclude mcp_runtime_store from the ConfigPage overlay audit The new mcp_runtime_store field is MCP-domain config surfaced on the dedicated /mcp-servers page (like mcp_servers itself), not the general ConfigPage, so every_kernel_config_struct_field_is_exposed_via_overlay must list it in EXCLUDED. --------- Co-authored-by: Evan <[email protected]>
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Summary
Bounded storage slice of #6021 — SQLite-backed MCP server configuration, so
config.tomlcan be a read-only ConfigMap on Kubernetes and MCP servers can be managed in the database.The codebase already has a mature SQLite substrate (a migration ladder + per-table stores sharing one r2d2 pool), so this extends that pattern rather than introducing new infra.
Change
migration.rs):SCHEMA_VERSION42 → 43;migrate_v43createsmcp_server_configs(name TEXT PK, entry_json TEXT NOT NULL, created_at, updated_at)+ an audit row. The fullMcpServerConfigEntryis stored as one JSON blob so the table tracks the struct without a per-field schema migration.McpConfigStore(newlibrefang-memory/src/mcp_config_store.rs):upsert/get/load_all/delete/countover the shared pool.upsertusesON CONFLICT(name) DO UPDATEsocreated_atsurvives andupdated_atrefreshes;load_allis ordered by name for a deterministic boot merge. 6 unit tests.kernel/boot.rs): loads DB MCP configs and overlays them over the file-backed[[mcp_servers]]by name (DB overrides file; DB-only names appended; empty table is a byte-for-byte no-op so file-only setups are unchanged). On store error it logswarn!and continues with the file config — the DB is an augmentation, not a hard boot dependency.Scope / deferred (follow-ups)
POST /api/mcp/servers) and the CLI (librefang mcp add/rm) ontoMcpConfigStore— needs a DB-vs-file write toggle (e.g.[mcp] storage = "db") so K8s deployments opt into DB writes.config_reload/reload_mcp_serversfor hot-reload (boot-time load only for now).config.toml→ DB import path.Test plan
cargo test -p librefang-memory mcp_config_storecargo test -p librefang-memory migrationcargo build -p librefang-kernel && cargo clippy -p librefang-memory -p librefang-kernel -- -D warningsRefs #6021 (storage + boot-merge slice; API/CLI wiring is a follow-up).