glm-5.3-flash
4a825d33e7
Full-surface integration suite (tests/full_surface.rs, mcp feature): - one HttpAdapter over real TCP (ProtocolHandler::handle path) serving gateway endpoints, /openapi.json, /mcp, and the WS channels session - gateway: search/schema/call/subscribe/batch/publish presence, envelope shapes, error fidelity end-to-end - from_openapi import -> Internal-by-default invisible from the wire -> External facade composes it via env.invoke -> upstream HTTP API called end-to-end (ADR-015 composition model exercised) - to_openapi 6-path doc validated against openapiv3 over the wire - to_mcp: MCP client connects to /mcp on the served adapter, lists the 4 gateway tools, search returns ACL-filtered ops (Sub excluded) Production fix: the WS upgrade route was reserved but never wired into HttpAdapter's router (the ws-upgrade-session tests built their own router). Now wired with ws_bearer_auth (401 without a resolvable token) around ws_upgrade_handler. Docs sync: all 28 'Port notes' sections/blockquotes stripped from ported ADRs/specs; OQ-01/OQ-02 statuses corrected to resolved in overview.md, websocket.md, and the README table (open-questions.md was already current). Publish prep: cargo publish --dry-run --allow-dirty succeeds; cargo doc --no-deps warning-free (ADR link targets fixed); feature combinations (default / test-support / mcp / wss / all) compile warning-free under clippy -D warnings. Verified: cargo test (182 lib default), --all-features (227 lib + 29 integration), clippy -D warnings x3 feature sets, fmt, doc, publish --dry-run.
159 lines
7.9 KiB
Markdown
159 lines
7.9 KiB
Markdown
# ADR-039: HTTP Server and Client Host Colocated in alkhttp
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*Ported from alknet ADR-039 (HTTP Server and Client Host Colocated in alknet-http); re-targeted to alkhttp.*
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## Status
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Proposed
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## Context
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alkhttp has two roles: an HTTP server (the `HttpAdapter`
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`ProtocolHandler` for `h2`/`http/1.1`, built on `axum`/`hyper`)
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and an HTTP client host (the `from_openapi`/`from_mcp` forwarding
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handlers, built on `reqwest`). The question is whether these two
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directions live in one crate (alkhttp) or are split into two
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crates (an HTTP-server crate + an HTTP-client crate).
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ADR-003 lists the HTTP crate as a single crate with dependency
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`alkcall, axum` and justifies the per-handler-crate decomposition
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with "each handler is self-contained — it receives a byte stream and
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manages its own protocol." That rationale covers the server side (the
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`HttpAdapter` is self-contained), but it does not address the
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within-crate dual-role question: should the inbound HTTP server and
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the outbound HTTP client (the adapter forwarding handlers) be
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colocated, or split?
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This is a load-bearing choice. Once published, downstream consumers
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build import paths against the crate boundary; the shared `reqwest::Client`
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and the no-env-vars invariant boundary (ADR-014) are scoped by it; the
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`to_openapi`/`to_mcp` projections are pure-registry-consumers that
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*describe* the server surface but live where the adapter types do.
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Splitting later would be a rewrite of every consumer's import paths,
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not a cheap revert. It needs an ADR.
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## Decision
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**One crate — alkhttp houses both the HTTP server and the HTTP
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client host (the adapter forwarding handlers and the `to_*` projections).**
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The two directions share the HTTP dependencies and HTTP-specific
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concerns that make splitting them counterproductive:
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- **Shared HTTP dependencies.** Both `axum` (server) and `reqwest`
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(client) pull in `hyper`, `http`, `http-body`, `rustls`/TLS stack
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types, and the HTTP header/status code types. A split into two crates
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would either duplicate these dependencies across both crates or
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force a third shared-types crate, neither of which is an improvement.
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- **Shared HTTP-specific concerns.** Both directions care about HTTP
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headers, status codes, content types, SSE framing, streaming vs
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non-streaming bodies, and TLS trust stores. The `from_openapi`
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forwarding handler's error mapping (HTTP status → `HTTP_<status>`
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error codes, ADR-023) and the `to_openapi` projection's error mapping
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(`ErrorDefinition.http_status` → HTTP response status) are *the same
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mapping* read in two directions — splitting them would put the two
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halves in different crates.
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- **The `to_*` projections describe the server surface.** `to_openapi`
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generates an OpenAPI doc whose paths mirror the gateway HTTP routes
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the `HttpAdapter` serves (ADR-036's mapping, superseded by ADR-047 —
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see [ADR-047](047-remove-direct-call-http-surface.md)).
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`to_mcp` exposes the
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same operations as MCP tools. These projections consume the
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`OperationRegistry` and produce specs; they live with the adapter
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types (in alkhttp, per the adapter location map — see
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the alkcall crate docs, client-and-adapters)
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because they share the operation-spec→HTTP mapping logic with the
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server's request dispatch.
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- **The no-env-vars invariant boundary is crate-scoped.** The
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`from_openapi`/`from_mcp` forwarding handlers are the credential
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injection point (ADR-014). The invariant — "no handler reads outbound
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credentials from any source other than `OperationContext.capabilities`"
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— is verified against the handler implementations in this crate. A
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split would put the invariant verification boundary across two crates.
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### What this does NOT change
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- ADR-003's rule "no handler crate depends on another handler crate"
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applies to peer handler crates (alkhttp does not depend on
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`alknet-ssh`). The alkhttp → `alkcall` edge is the
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protocol-foundation exception (ADR-003 Amendment 1). This ADR is
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about the *internal* structure of alkhttp, not its dependency
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edges.
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- The adapter location map (the `OperationAdapter` trait in
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`alkcall`; the HTTP-backed adapter implementations in
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alkhttp) is unchanged. This ADR records *why* the HTTP-backed
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adapters live in the same crate as the HTTP server, not whether they
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live in alkhttp vs `alkcall`.
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## Consequences
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**Positive:**
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- One crate, one set of HTTP dependencies, one HTTP-specific concern
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surface. No duplicated `hyper`/`http` types across two crates, no
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shared-types crate needed.
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- The `to_*` projections live with the server whose surface they
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describe, and with the adapter types they consume. The operation-spec
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→ HTTP mapping logic is in one place.
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- The no-env-vars invariant verification boundary is one crate. The
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`from_openapi`/`from_mcp` handlers and the credential injection
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logic they share are co-located.
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- A downstream consumer wires one crate (alkhttp) into the
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`HandlerRegistry` and gets the full HTTP surface — server + adapters +
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projections. No two-crate wiring.
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**Negative:**
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- A deployment that only needs the HTTP server (no `from_openapi`/`from_
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mcp` forwarding) still compiles the `reqwest` dependency. Mitigated:
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the `mcp` feature is already gated (ADR-037); the `from_openapi`
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forwarding is always available but the `reqwest` client is only
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constructed if a `from_openapi`/`from_mcp` adapter is registered at
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assembly time. The dependency is compiled, the client is lazy.
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- A deployment that only needs the HTTP client (e.g., an agent crate
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that only uses `from_openapi` forwarding, no inbound HTTP) still
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compiles `axum`/`hyper`. This is the rarer case — the agent crate
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(alknet-agent) consumes `alkcall` directly for tool dispatch
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and uses `from_openapi` via alkhttp's adapter, but doesn't
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serve inbound HTTP itself. In practice, the agent deployment wires
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alkhttp for the adapters and the CLI wires it for the server;
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the compile cost is paid once per workspace, not once per deployment.
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- The crate is larger than a single-direction crate would be. This is
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the cost of colocating shared concerns; the alternative (two crates
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+ a shared types crate) is more crates, not less code.
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## Assumptions
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1. **The shared-HTTP-dependencies argument holds.** `axum` and
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`reqwest` both pull in `hyper` and the `http` crate's types; the
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shared types (headers, status codes, method, URI) are the same. If
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a future version of `axum` or `reqwest` diverges its HTTP types
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(e.g., `axum` moves to a different HTTP implementation), this
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argument weakens. As of `axum` 0.7+ and `reqwest` 0.12+, both are
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built on `hyper` 1.x and share `http` types.
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2. **The `to_*` projections share enough mapping logic with the server
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to justify colocation.** The operation-spec → HTTP path/method/
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error-status mapping is the same in both directions. If the
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projections turn out to be pure registry-consumers with no
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HTTP-mapping logic (just spec serialization), the colocation
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argument is weaker — but the current design (ADR-036, ADR-023)
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has them sharing the mapping.
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## References
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- [ADR-003](003-crate-decomposition.md) — crate decomposition (this
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ADR addresses the within-alkhttp dual-role question, not the
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dependency edge; Amendment 1 covers the `alkcall` edge)
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- [ADR-014](014-secret-material-flow-and-capability-injection.md) —
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the no-env-vars invariant whose verification boundary is crate-scoped
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- [ADR-017](017-call-protocol-client-and-adapter-contract.md) — the
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adapter contract; `to_*` are projections
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- [ADR-023](023-operation-error-schemas.md) — the error mapping shared
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between `from_openapi` (status → code) and `to_openapi` (code →
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status)
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- [ADR-036](036-http-to-call-operation-mapping.md) — the HTTP path =
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operation path mapping shared between server dispatch and `to_openapi`
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- [ADR-037](037-mcp-stdio-transport-exclusion.md) — the `mcp` feature
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gate
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- `overview.md` — the crate overview (the inline rationale
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for this decision is replaced by a pointer to this ADR)
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