mangle-server

HTTP server for evaluating Mangle programs. Wraps the Rust mangle-driver compilation and execution pipeline behind a JSON API.

Usage

cargo run -p mangle-server -- [OPTIONS]

Options

Example

# Start with pre-loaded programs
cargo run -p mangle-server -- --port 8090 --programs-dir ./programs/

API

All endpoints accept and return application/json. On error, the response body is { "error": "<message>" } with an appropriate HTTP status code (400, 404, or 500).

POST /programs

Load a named program. The source is compiled to extract predicate names and stored for later querying.

curl -X POST http://localhost:8090/programs \
  -H 'Content-Type: application/json' \
  -d '{"name": "social", "source": "friend(\"alice\", \"bob\"). friend(\"bob\", \"carol\")."}'

Response:

{ "name": "social", "predicates": ["friend"] }

GET /programs

List all loaded programs and their predicates.

curl http://localhost:8090/programs

Response:

{ "programs": [{ "name": "social", "predicates": ["friend"] }] }

POST /query

Query a relation from a loaded program. The program is recompiled and executed on each query.

curl -X POST http://localhost:8090/query \
  -H 'Content-Type: application/json' \
  -d '{"program": "social", "query": "friend(X, Y)"}'

Response:

{ "results": [["alice", "bob"], ["bob", "carol"]] }

The query string must be a valid Mangle atom (e.g. predicate(X, Y)). The predicate name is extracted to determine which relation to scan. All tuples from that relation are returned.

POST /eval

Compile and execute ephemeral source without storing it. Useful for one-off evaluation.

curl -X POST http://localhost:8090/eval \
  -H 'Content-Type: application/json' \
  -d '{
    "source": "edge(1,2). edge(2,3). path(X,Y) :- edge(X,Y). path(X,Z) :- edge(X,Y), path(Y,Z).",
    "query": "path(1, X)"
  }'

Response:

{ "results": [[2], [3]] }

If query is omitted, all derived facts across all relations are returned.

Value encoding

Mangle values map to JSON as follows:

Result tuples are returned as arrays of arrays: [[val, ...], ...].

Mangle syntax notes

String constants in Mangle source must be double-quoted: greeting("hello"), not greeting(hello). Unquoted lowercase identifiers are not valid constant syntax. Numbers are unquoted: p(1, 2). Variables start with an uppercase letter: q(X) :- p(X).

Container image

A Containerfile is provided for building with Podman:

podman build -t localhost/mangle-server:latest -f rust/server/Containerfile rust/
podman run -p 8090:8090 localhost/mangle-server:latest

Pass arguments after the image name:

podman run -p 8090:8090 -v ./programs:/programs:ro \
  localhost/mangle-server:latest --programs-dir /programs