| 1 | import type { ModelUpstream } from "@g1t/contracts"; |
| 2 | |
| 3 | /** g1t's own way to the models, for runs it pays for. */ |
| 4 | export type HostedRouting = { |
| 5 | /** A Cloudflare AI Gateway id; empty sends requests to Anthropic directly. */ |
| 6 | AI_GATEWAY_ID: string; |
| 7 | CLOUDFLARE_ACCOUNT_ID: string; |
| 8 | /** Authenticates to the gateway, which holds g1t's key. */ |
| 9 | AI_GATEWAY_TOKEN?: string; |
| 10 | /** g1t's key, when the gateway does not hold it. */ |
| 11 | ANTHROPIC_API_KEY?: string; |
| 12 | /** |
| 13 | * A Cloudflare API token that may run Workers AI on g1t's account, for |
| 14 | * the AI Gateway's open models. Without one, `AI_GATEWAY_TOKEN` is tried. |
| 15 | */ |
| 16 | WORKERS_AI_TOKEN?: string; |
| 17 | }; |
| 18 | |
| 19 | /** Headers the sandbox sends that never go further. */ |
| 20 | const DROPPED = new Set([ |
| 21 | "x-api-key", |
| 22 | "authorization", |
| 23 | "host", |
| 24 | "cf-aig-authorization", |
| 25 | "cf-aig-metadata", |
| 26 | "cf-connecting-ip", |
| 27 | "x-forwarded-for", |
| 28 | "x-real-ip", |
| 29 | ]); |
| 30 | |
| 31 | /** The token a sandbox sends instead of a key, from either header. */ |
| 32 | export function presentedToken(headers: Headers): string | null { |
| 33 | const key = headers.get("x-api-key"); |
| 34 | if (key) return key.trim(); |
| 35 | const bearer = headers.get("authorization")?.match(/^Bearer\s+(.+)$/i); |
| 36 | return bearer ? bearer[1].trim() : null; |
| 37 | } |
| 38 | |
| 39 | /** |
| 40 | * The caller's headers, less its token and anything that never goes |
| 41 | * further. Every `cf-aig-` header is the proxy's to set: one from a caller |
| 42 | * could change how Cloudflare's AI Gateway logs, caches or prices a |
| 43 | * request (`cf-aig-custom-cost`), which billing settles by. |
| 44 | */ |
| 45 | export function passedHeaders(incoming: Headers): Headers { |
| 46 | const headers = new Headers(); |
| 47 | for (const [name, value] of incoming) { |
| 48 | const lower = name.toLowerCase(); |
| 49 | if (!DROPPED.has(lower) && !lower.startsWith("cf-aig-")) headers.set(name, value); |
| 50 | } |
| 51 | return headers; |
| 52 | } |
| 53 | |
| 54 | /** |
| 55 | * Where one request goes and what it carries: the sandbox's request, |
| 56 | * stripped of its token, with the credentials for the run's route. |
| 57 | * `path` is what follows `/anthropic`, such as `/v1/messages?beta=true`. |
| 58 | */ |
| 59 | export function upstreamRequest( |
| 60 | upstream: ModelUpstream, |
| 61 | hosted: HostedRouting, |
| 62 | path: string, |
| 63 | incoming: Headers, |
| 64 | ): { url: string; headers: Headers } { |
| 65 | const headers = passedHeaders(incoming); |
| 66 | if (upstream.route === "g1t") { |
| 67 | if (!hosted.AI_GATEWAY_ID) { |
| 68 | if (hosted.ANTHROPIC_API_KEY) headers.set("x-api-key", hosted.ANTHROPIC_API_KEY); |
| 69 | return { url: `https://api.anthropic.com${path}`, headers }; |
| 70 | } |
| 71 | // The gateway logs these with every request, so spend and failures can |
| 72 | // be read per kind of work, tier, repository and pull request. It keeps |
| 73 | // five entries and drops the rest, so the tier takes the workspace's |
| 74 | // place: the repository names the workspace too. A run from before |
| 75 | // routing by tier has no tier, and keeps the workspace. |
| 76 | headers.set( |
| 77 | "cf-aig-metadata", |
| 78 | JSON.stringify({ |
| 79 | task: upstream.task, |
| 80 | ...(upstream.tier ? { tier: upstream.tier } : { workspace: upstream.workspace }), |
| 81 | repo: upstream.repo, |
| 82 | pull: upstream.number, |
| 83 | // What billing finds the run's requests by, to charge what they cost. |
| 84 | session: upstream.session, |
| 85 | }), |
| 86 | ); |
| 87 | if (hosted.AI_GATEWAY_TOKEN) headers.set("cf-aig-authorization", `Bearer ${hosted.AI_GATEWAY_TOKEN}`); |
| 88 | if (hosted.ANTHROPIC_API_KEY) headers.set("x-api-key", hosted.ANTHROPIC_API_KEY); |
| 89 | return { |
| 90 | url: `https://gateway.ai.cloudflare.com/v1/${hosted.CLOUDFLARE_ACCOUNT_ID}/${hosted.AI_GATEWAY_ID}/anthropic${path}`, |
| 91 | headers, |
| 92 | }; |
| 93 | } |
| 94 | const key = upstream.apiKey; |
| 95 | if (key) { |
| 96 | const header = upstream.authHeader ?? "x-api-key"; |
| 97 | headers.set(header, header === "authorization" ? `Bearer ${key}` : key); |
| 98 | } |
| 99 | if (upstream.gatewayToken) headers.set("cf-aig-authorization", `Bearer ${upstream.gatewayToken}`); |
| 100 | const base = (upstream.baseUrl ?? "https://api.anthropic.com").replace(/\/+$/, ""); |
| 101 | return { url: `${base}${path}`, headers }; |
| 102 | } |