feat(core): add transient session generation (#37330)

packages/core/src/session/generate-node.ts

@@ -0,0 +1,69 @@
+export * as SessionGenerateNode from "./generate-node"
+
+import { LLM, LLMClient, Message, SystemPart } from "@opencode-ai/ai"
+import { Effect, Layer } from "effect"
+import { Database } from "../database/database"
+import { makeLocationNode } from "../effect/app-node"
+import { llmClient } from "../effect/app-node-platform"
+import { PluginHooks } from "../plugin/hooks"
+import { SessionContext } from "./context"
+import { SessionGenerate } from "./generate"
+import { SessionHistory } from "./history"
+import { SessionModelHeaders } from "./model-headers"
+import { SessionRunnerModel } from "./runner/model"
+import PROMPT_DEFAULT from "./runner/prompt/base.txt"
+import { toLLMMessages } from "./runner/to-llm-message"
+
+const layer = Layer.effect(
+  SessionGenerate.Service,
+  Effect.gen(function* () {
+    const context = yield* SessionContext.Service
+    const database = yield* Database.Service
+    const hooks = yield* PluginHooks.Service
+    const llm = yield* LLMClient.Service
+    const models = yield* SessionRunnerModel.Service
+
+    return SessionGenerate.Service.of({
+      generate: Effect.fn("SessionGenerate.generate")(function* (input) {
+        const selection = yield* context.select(input.sessionID)
+        const model = yield* models.resolve(selection.session)
+        const history = yield* SessionHistory.preview(database.db, selection.session.id, selection.instructions)
+        const providerMetadataKey = model.model.route.providerMetadataKey ?? model.model.provider
+        const promptCacheKey = /^ses_[0-9a-f]{64}$/.test(selection.session.id)
+          ? selection.session.id.slice(4)
+          : selection.session.id
+        const contextEvent = yield* hooks.trigger("session", "context", {
+          sessionID: selection.session.id,
+          agent: selection.agent.id,
+          model: model.ref,
+          system: [selection.agent.info.system ? selection.agent.info.system : PROMPT_DEFAULT, history.initial]
+            .filter((part) => part.length > 0)
+            .map(SystemPart.make),
+          messages: [
+            ...toLLMMessages(history.messages, model.ref, providerMetadataKey),
+            ...(history.instructionUpdate ? [Message.system(history.instructionUpdate)] : []),
+            Message.user(input.prompt),
+          ],
+          tools: {},
+        })
+        return (yield* llm.generate(
+          LLM.request({
+            model: model.model,
+            http: { headers: SessionModelHeaders.make(selection.session) },
+            providerOptions: { openai: { promptCacheKey } },
+            system: contextEvent.system,
+            messages: contextEvent.messages,
+            tools: [],
+            toolChoice: "none",
+          }),
+        )).text
+      }),
+    })
+  }),
+)
+
+export const node = makeLocationNode({
+  service: SessionGenerate.Service,
+  layer,
+  deps: [SessionContext.node, Database.node, PluginHooks.node, SessionRunnerModel.node, llmClient],
+})