feat(backend): support container runtime paths

backend/src/app.ts

@@ -34,6 +34,7 @@ export function buildApp(config: AppConfig, deps?: BuildAppDeps): FastifyInstanc
     thtBin: config.thtBin,
     harnessDir: config.harnessDir,
     configPath: "config/tht.yaml",
+    dataRoot: config.dataRoot,
   });
   const mgr = deps?.mgr ?? new PiProcessManager(config, deps?.spawnFn ? { spawnFn: deps.spawnFn } : undefined);
   const hub = new SseHub();

backend/src/config.ts

@@ -1,13 +1,15 @@
 export interface AppConfig {
-  port: number; harnessDir: string; thtBin: string; piBin: string;
+  host: string; port: number; harnessDir: string; thtBin: string; piBin: string;
   authMode: "none" | "mock" | "oidc";
   defaults: { provider?: string; model?: string; thinking?: string };
   maxPiProcesses: number;
   settingsFile: string;
+  dataRoot?: string;
   ollamaEnsureTimeoutMs: number;
 }
 export function loadConfig(env: Record<string, string | undefined>): AppConfig {
   return {
+    host: env.HOST ?? "127.0.0.1",
     port: Number(env.PORT ?? 8787),
     harnessDir: env.THT_HARNESS_DIR ?? "../harness",
     thtBin: env.THT_BIN ?? "tht",
@@ -16,6 +18,7 @@ export function loadConfig(env: Record<string, string | undefined>): AppConfig {
     defaults: { provider: env.PI_PROVIDER, model: env.PI_MODEL, thinking: env.PI_THINKING },
     maxPiProcesses: Number(env.MAX_PI_PROCESSES ?? 4),
     settingsFile: env.SETTINGS_FILE ?? "data/settings.json",
+    dataRoot: env.THT_DATA_ROOT,
     ollamaEnsureTimeoutMs: Number(env.OLLAMA_ENSURE_TIMEOUT_MS ?? 60000),
   };
 }

backend/src/pi/list-models.ts

@@ -1,5 +1,4 @@
 import { spawn as nodeSpawn, type ChildProcessWithoutNullStreams } from "node:child_process";
-import { join } from "node:path";
 import type { AppConfig } from "../config.js";
 import { RpcClient } from "../rpc/rpc-client.js";
 
@@ -11,7 +10,11 @@ export interface PiModel {
 }
 
 interface Opts {
-  spawnFn?: () => ChildProcessWithoutNullStreams;
+  spawnFn?: (
+    command: string,
+    args: string[],
+    options: { cwd: string; env: NodeJS.ProcessEnv },
+  ) => ChildProcessWithoutNullStreams;
   ttlMs?: number;
   nowMs?: () => number;
 }
@@ -24,22 +27,16 @@ interface Opts {
 export function createPiModelLister(cfg: AppConfig, opts: Opts = {}): () => Promise<PiModel[]> {
   const ttlMs = opts.ttlMs ?? 60_000;
   const now = opts.nowMs ?? (() => Date.now());
-  const spawnFn =
-    opts.spawnFn ??
-    (() => {
-      const harnessVenvBin = join(cfg.harnessDir, ".venv", "bin");
-      return nodeSpawn(cfg.piBin, ["--mode", "rpc"], {
-        cwd: cfg.harnessDir,
-        env: { ...process.env, PATH: `${harnessVenvBin}:${process.env.PATH ?? ""}` },
-      }) as ChildProcessWithoutNullStreams;
-    });
+  const spawnFn = opts.spawnFn ?? nodeSpawn;
 
   let cache: { at: number; models: PiModel[] } | null = null;
 
   return async function listModels(): Promise<PiModel[]> {
     if (cache && now() - cache.at < ttlMs) return cache.models;
 
-    const child = spawnFn();
+    const env: NodeJS.ProcessEnv = { ...process.env };
+    if (cfg.dataRoot !== undefined) env.THT_DATA_ROOT = cfg.dataRoot;
+    const child = spawnFn(cfg.piBin, ["--mode", "rpc"], { cwd: cfg.harnessDir, env });
     child.stderr.resume();
     const rpc = new RpcClient(child);
     try {

backend/src/pi/pi-process-manager.ts

@@ -1,5 +1,4 @@
 import { spawn as nodeSpawn, type ChildProcessWithoutNullStreams } from "node:child_process";
-import { join } from "node:path";
 import type { AppConfig } from "../config.js";
 import { RpcClient } from "../rpc/rpc-client.js";
 import { SessionBridge } from "../bridge/session-bridge.js";
@@ -11,8 +10,12 @@ export interface SessionRuntime {
   child: ChildProcessWithoutNullStreams;
 }
 
-/** Injected test double signature: produce a child process, no args needed. */
-type SpawnFn = () => ChildProcessWithoutNullStreams;
+/** Injectable child-process boundary; callbacks may ignore arguments in simpler tests. */
+type SpawnFn = (
+  command: string,
+  args: string[],
+  options: { cwd: string; env: NodeJS.ProcessEnv },
+) => ChildProcessWithoutNullStreams;
 
 export class PiProcessManager {
   private runtimes = new Map<string, SessionRuntime>();
@@ -20,30 +23,29 @@ export class PiProcessManager {
 
   constructor(private cfg: AppConfig, opts?: { spawnFn?: SpawnFn }) {
     if (opts?.spawnFn) {
-      this.spawnFn = () => opts.spawnFn!();
+      this.spawnFn = (sessionId: string, author: string) => this.spawnPi(opts.spawnFn!, sessionId, author);
     } else {
-      this.spawnFn = (sessionId: string, author: string) => {
-        const harnessVenvBin = join(cfg.harnessDir, ".venv", "bin");
-        const env: NodeJS.ProcessEnv = {
-          ...process.env,
-          THT_SESSION: sessionId,
-          THT_AUTHOR: author,
-          PATH: `${harnessVenvBin}:${process.env.PATH ?? ""}`,
-        };
-        // pi 0.73 (the @mariozechner rebrand) removed the `--approve` flag: rpc mode is
-        // headless and runs tools without an approval gate, so passing it makes pi exit
-        // with "Unknown option: --approve". Args are intentionally just `--mode rpc`.
-        const child = nodeSpawn(cfg.piBin, ["--mode", "rpc"], {
-          cwd: cfg.harnessDir,
-          env,
-        });
-        // Drain stderr so the child's stderr buffer never blocks the process.
-        child.stderr.resume();
-        return child;
-      };
+      this.spawnFn = (sessionId: string, author: string) => this.spawnPi(nodeSpawn, sessionId, author);
     }
   }
 
+  private spawnPi(spawnFn: SpawnFn, sessionId: string, author: string): ChildProcessWithoutNullStreams {
+    const env: NodeJS.ProcessEnv = {
+      ...process.env,
+      THT_SESSION: sessionId,
+      THT_AUTHOR: author,
+    };
+    if (this.cfg.dataRoot !== undefined) env.THT_DATA_ROOT = this.cfg.dataRoot;
+    // pi 0.73 removed `--approve`: rpc mode is headless and its argv is intentionally minimal.
+    const child = spawnFn(this.cfg.piBin, ["--mode", "rpc"], {
+      cwd: this.cfg.harnessDir,
+      env,
+    });
+    // Drain stderr so the child's stderr buffer never blocks the process.
+    child.stderr.resume?.();
+    return child;
+  }
+
   count(): number { return this.runtimes.size; }
 
   get(id: string): SessionRuntime | undefined { return this.runtimes.get(id); }

backend/src/server.ts

@@ -2,5 +2,5 @@ import { buildApp } from "./app.js";
 import { loadConfig } from "./config.js";
 const config = loadConfig(process.env);
 const app = buildApp(config);
-app.listen({ port: config.port, host: "127.0.0.1" })
+app.listen({ port: config.port, host: config.host })
   .then((addr) => console.log(`backend listening on ${addr}`));

backend/src/tht/tht-runner.ts

@@ -6,6 +6,7 @@ export interface ThtConfig {
   thtBin: string;
   harnessDir: string;
   configPath: string;
+  dataRoot?: string;
 }
 
 export interface SessionRow {
@@ -61,8 +62,11 @@ export class ThtRunner {
 
   run(args: string[], workspace?: string): Promise<{ code: number; stdout: string; stderr: string }> {
     return new Promise((resolve) => {
+      const env: NodeJS.ProcessEnv = { ...process.env };
+      if (this.cfg.dataRoot !== undefined) env.THT_DATA_ROOT = this.cfg.dataRoot;
       const ch = spawn(this.cfg.thtBin, this.buildArgv(args, workspace), {
         cwd: this.cfg.harnessDir,
+        env,
       });
       let stdout = "";
       let stderr = "";

backend/test/config.test.ts

@@ -0,0 +1,34 @@
+import { expect, test } from "vitest";
+import { loadConfig } from "../src/config.js";
+
+test("loadConfig accepts container listening and runtime paths", () => {
+  expect(loadConfig({
+    HOST: "0.0.0.0",
+    PORT: "9000",
+    THT_HARNESS_DIR: "/app/harness",
+    THT_BIN: "/opt/venv/bin/tht",
+    PI_BIN: "/usr/local/bin/pi",
+    SETTINGS_FILE: "/data/settings/settings.json",
+    THT_DATA_ROOT: "/data",
+  })).toMatchObject({
+    host: "0.0.0.0",
+    port: 9000,
+    harnessDir: "/app/harness",
+    thtBin: "/opt/venv/bin/tht",
+    piBin: "/usr/local/bin/pi",
+    settingsFile: "/data/settings/settings.json",
+    dataRoot: "/data",
+  });
+});
+
+test("loadConfig keeps local development defaults", () => {
+  expect(loadConfig({})).toMatchObject({
+    host: "127.0.0.1",
+    port: 8787,
+    harnessDir: "../harness",
+    thtBin: "tht",
+    piBin: "pi",
+    settingsFile: "data/settings.json",
+  });
+  expect(loadConfig({}).dataRoot).toBeUndefined();
+});

backend/test/list-models.test.ts

@@ -51,3 +51,33 @@ test("createPiModelLister caches within ttl (spawns once for two calls)", async
     rmSync(path.dirname(script), { recursive: true, force: true });
   }
 });
+
+test("production model-list spawn preserves PATH and passes the portable data root", async () => {
+  const script = scriptWith([]);
+  const calls: any[][] = [];
+  const previousPath = process.env.PATH;
+  process.env.PATH = "/usr/local/bin:/usr/bin";
+  try {
+    const lister = createPiModelLister(loadConfig({
+      THT_HARNESS_DIR: "/app/harness",
+      PI_BIN: "/usr/local/bin/pi",
+      THT_DATA_ROOT: "/data",
+    }), {
+      spawnFn: (...args: any[]) => {
+        calls.push(args);
+        return spawn("node", [FAKE, script]) as any;
+      },
+    });
+    await lister();
+    expect(calls[0][0]).toBe("/usr/local/bin/pi");
+    expect(calls[0][1]).toEqual(["--mode", "rpc"]);
+    expect(calls[0][2]).toMatchObject({
+      cwd: "/app/harness",
+      env: expect.objectContaining({ PATH: "/usr/local/bin:/usr/bin", THT_DATA_ROOT: "/data" }),
+    });
+  } finally {
+    if (previousPath === undefined) delete process.env.PATH;
+    else process.env.PATH = previousPath;
+    rmSync(path.dirname(script), { recursive: true, force: true });
+  }
+});

backend/test/pi-process-manager.test.ts

@@ -1,4 +1,4 @@
-import { test, expect } from "vitest";
+import { test, expect, vi } from "vitest";
 import { spawn } from "node:child_process";
 import path from "node:path";
 import { fileURLToPath } from "node:url";
@@ -125,3 +125,38 @@ test("spawnFor default (new) mode sends /nuova-domanda", async () => {
   expect(child._writes.join("")).toContain("/nuova-domanda");
   mgr.teardown("sid-10");
 });
+
+test("production spawn uses explicit Pi path and passes portable data root without rewriting PATH", async () => {
+  vi.stubEnv("PATH", "/usr/local/bin:/usr/bin");
+  vi.stubEnv("PI_PROVIDER_API_KEY", "provider-secret");
+  vi.stubEnv("NODE_EXTRA_CA_CERTS", "/certs/company-ca.pem");
+  const calls: any[][] = [];
+  const child = recordingChild();
+  child.stderr.resume = () => {};
+  const spawnFn = (...args: any[]) => { calls.push(args); return child as any; };
+  const cfg = loadConfig({
+    THT_HARNESS_DIR: "/app/harness",
+    PI_BIN: "/usr/local/bin/pi",
+    THT_DATA_ROOT: "/data",
+  });
+  const mgr = new PiProcessManager(cfg, { spawnFn });
+
+  try {
+    await mgr.spawnFor("portable-session", { author: "user@example.test" });
+    const [bin, args, options] = calls[0];
+    expect(bin).toBe("/usr/local/bin/pi");
+    expect(args).toEqual(["--mode", "rpc"]);
+    expect(options.cwd).toBe("/app/harness");
+    expect(options.env).toMatchObject({
+      PATH: "/usr/local/bin:/usr/bin",
+      PI_PROVIDER_API_KEY: "provider-secret",
+      NODE_EXTRA_CA_CERTS: "/certs/company-ca.pem",
+      THT_DATA_ROOT: "/data",
+      THT_SESSION: "portable-session",
+      THT_AUTHOR: "user@example.test",
+    });
+  } finally {
+    mgr.teardown("portable-session");
+    vi.unstubAllEnvs();
+  }
+});