Dgraph

zero exposes Dgraph through a new ctx.Graph handle. Dgraph is a distributed graph database that speaks GraphQL± over HTTP, and zero reaches it with a small pure-Zig client.

Configuration

DGRAPH_URL=http://localhost:8080
DGRAPH_API_KEY=            # optional; sent as X-Dgraph-AccessToken

API

ctx.Graph has two calls — query and mutate:

pub fn queryGraph(ctx: *Context) !void {
    const q =
        \\query {
        \\  all(func: has(name)) {
        \\    name
        \\  }
        \\};
    const res = try ctx.Graph.?.query(ctx, q);
    defer ctx.allocator.free(res);
    try ctx.json(res);
}

pub fn mutateGraph(ctx: *Context) !void {
    const m =
        \\{ "set": [ { "name": "Zero", "type": "Framework" } ] };
    _ = try ctx.Graph.?.mutate(ctx, m);
}

• query(ctx, q) — POSTs the body to {url}/query (content-type application/graphql).
• mutate(ctx, m) — POSTs the body to {url}/mutate (content-type application/json).
• lastError() — surfaces the upstream status.

ctx.Graph is optional — guard with if (ctx.Graph) |g| { ... }. Free the returned slice with ctx.allocator.

Caveats

• Only query and mutate are exposed; there is no schema/alter or upsert helper.
• The auth header is X-Dgraph-AccessToken (not Bearer).
• No circuit breaker is wired yet.

See the runnable zero-graph example and the implementation in src/datasource/graph/dgraph.zig.