feat(server): implement workflow triggering and enhance script execution

- Added support for triggering workflows via a new triggerWorkflow function, allowing for fire-and-forget execution of workflows with optional data transformation using JSONata.
- Introduced a $workflows API in the script sandbox for accessing workflow triggers.
- Enhanced existing script execution functions to accommodate the new workflow triggering capabilities.
- Updated workflow-mermaid.js and WorkflowsPage to reflect the new workflow type in labels for better clarity.

packages/server/registry.js

@@ -21,6 +21,18 @@ import * as fsStore from "./fs-store.js";
  * @typedef {{ owner: string, file: string, workflow: any }} WorkflowEntry
  */
 
+const MAX_WORKFLOW_TRIGGER_DEPTH = 8;
+
+/**
+ * @param {unknown} workflow
+ */
+function hasWorkflowTrigger(workflow) {
+  if (!workflow || typeof workflow !== "object") return false;
+  const triggers = /** @type {{ triggers?: Array<{ type?: string }> }} */ (workflow)
+    .triggers;
+  return (triggers ?? []).some((t) => t?.type === "workflow");
+}
+
 /**
  * @param {import("fastify").FastifyInstance} server
  */
@@ -36,6 +48,49 @@ export function createRegistry(server) {
   /** @type {Set<string>} */
   const registeredHttpRoutes = new Set();
 
+  /**
+   * Resolve a same-owner workflow that opts in with `type: workflow`.
+   * Prefers YAML `name`, then filename (`name` or `name.yaml`).
+   *
+   * @param {string} owner
+   * @param {string} name
+   */
+  function resolveWorkflowTriggerKey(owner, name) {
+    if (typeof name !== "string" || name.length === 0) {
+      throw new Error("workflow name is required");
+    }
+
+    /** @type {string[]} */
+    const byName = [];
+    for (const [key, entry] of workflows) {
+      if (entry.owner !== owner) continue;
+      if (entry.workflow?.enabled === false) continue;
+      if (!hasWorkflowTrigger(entry.workflow)) continue;
+      if (entry.workflow?.name === name) byName.push(key);
+    }
+    if (byName.length === 1) return byName[0];
+    if (byName.length > 1) {
+      throw new Error(`ambiguous workflow name "${name}"`);
+    }
+
+    const fileCandidates =
+      name.endsWith(".yaml") || name.endsWith(".yml")
+        ? [`${owner}/${name}`]
+        : [`${owner}/${name}`, `${owner}/${name}.yaml`];
+
+    for (const key of fileCandidates) {
+      const entry = workflows.get(key);
+      if (!entry) continue;
+      if (entry.workflow?.enabled === false) continue;
+      if (!hasWorkflowTrigger(entry.workflow)) continue;
+      return key;
+    }
+
+    throw new Error(
+      `workflow "${name}" not found or has no workflow trigger (owner "${owner}")`,
+    );
+  }
+
   function registerWorkflows() {
     workflows.clear();
     loadErrors.clear();
@@ -208,12 +263,22 @@ export function createRegistry(server) {
    * @param {import("pino").Logger} runLog
    * @param {string} key
    * @param {string} owner
+   * @param {number} depth
    */
-  async function runLinearSteps(compiled, ctx, runId, runLog, key, owner) {
+  async function runLinearSteps(compiled, ctx, runId, runLog, key, owner, depth) {
     let next = ctx;
     for (const index of compiled.order) {
       const parsed = compiled.steps[index];
-      next = await runCompiledStep(parsed, next, index, runId, runLog, key, owner);
+      next = await runCompiledStep(
+        parsed,
+        next,
+        index,
+        runId,
+        runLog,
+        key,
+        owner,
+        depth,
+      );
     }
     return next;
   }
@@ -225,8 +290,9 @@ export function createRegistry(server) {
    * @param {import("pino").Logger} runLog
    * @param {string} key
    * @param {string} owner
+   * @param {number} depth
    */
-  async function runDagSteps(compiled, ctx, runId, runLog, key, owner) {
+  async function runDagSteps(compiled, ctx, runId, runLog, key, owner, depth) {
     const triggerData = ctx.data;
     /** @type {Map<string, unknown>} */
     const outputsById = new Map();
@@ -243,6 +309,7 @@ export function createRegistry(server) {
         runLog,
         key,
         owner,
+        depth,
       );
       if (parsed.id) {
         outputsById.set(parsed.id, last);
@@ -251,6 +318,39 @@ export function createRegistry(server) {
     return last;
   }
 
+  /**
+   * @param {string} owner
+   * @param {string} parentKey
+   * @param {string} parentRunId
+   * @param {number} depth
+   */
+  function createWorkflowsApi(owner, parentKey, parentRunId, depth) {
+    return {
+      /**
+       * @param {string} name
+       * @param {unknown} [data]
+       */
+      async trigger(name, data) {
+        if (depth >= MAX_WORKFLOW_TRIGGER_DEPTH) {
+          throw new Error(
+            `workflow trigger depth limit (${MAX_WORKFLOW_TRIGGER_DEPTH}) exceeded`,
+          );
+        }
+        const destKey = resolveWorkflowTriggerKey(owner, name);
+        return runWorkflow(
+          destKey,
+          { data },
+          { type: "workflow", detail: parentKey },
+          {
+            parentRunId,
+            depth: depth + 1,
+            detach: true,
+          },
+        );
+      },
+    };
+  }
+
   /**
    * @param {import("./workflow-parse.js").CompiledStep} parsed
    * @param {{ data?: unknown, config?: unknown }} ctx
@@ -259,8 +359,18 @@ export function createRegistry(server) {
    * @param {import("pino").Logger} runLog
    * @param {string} key
    * @param {string} owner
+   * @param {number} depth
    */
-  async function runCompiledStep(parsed, ctx, index, runId, runLog, key, owner) {
+  async function runCompiledStep(
+    parsed,
+    ctx,
+    index,
+    runId,
+    runLog,
+    key,
+    owner,
+    depth,
+  ) {
     const script = parsed.kind === "set" ? SET_STEP_SCRIPT : parsed.script;
     const config = parsed.config;
     const step = await store.startStep({
@@ -292,6 +402,7 @@ export function createRegistry(server) {
         log: stepLog,
         workflowName: key,
         owner,
+        $workflows: createWorkflowsApi(owner, key, runId, depth),
       });
       await store.finishStep(step.id, "success", result);
       return result;
@@ -305,8 +416,17 @@ export function createRegistry(server) {
    * @param {string} key
    * @param {{ data?: unknown }} context
    * @param {{ type: string, detail?: string | null }} trigger
+   * @param {{
+   *   parentRunId?: string | null,
+   *   depth?: number,
+   *   detach?: boolean,
+   * }} [opts]
    */
-  async function runWorkflow(key, context, trigger) {
+  async function runWorkflow(key, context, trigger, opts = {}) {
+    const parentRunId = opts.parentRunId ?? null;
+    const depth = opts.depth ?? 0;
+    const detach = opts.detach === true;
+
     const entry = workflows.get(key);
     if (!entry) {
       log.error({ workflow: key }, "workflow not found");
@@ -320,21 +440,40 @@ export function createRegistry(server) {
       workflowName: workflow?.name,
       trigger,
       input: context.data,
+      parentRunId,
     });
     const runLog = log.child({ runId: run.id, owner, workflow: key });
-    runLog.debug("running workflow");
+    runLog.debug(detach ? "running workflow (detached)" : "running workflow");
 
-    let ctx = {
+    const initialCtx = {
       ...context,
       data: context.data ?? workflow.data ?? null,
     };
 
+    const execute = async () => {
+      let ctx = initialCtx;
       try {
         const compiled = compileWorkflowScripts(workflow.scripts);
         if (compiled.dagMode) {
-        ctx = await runDagSteps(compiled, ctx, run.id, runLog, key, owner);
+          ctx = await runDagSteps(
+            compiled,
+            ctx,
+            run.id,
+            runLog,
+            key,
+            owner,
+            depth,
+          );
         } else {
-        ctx = await runLinearSteps(compiled, ctx, run.id, runLog, key, owner);
+          ctx = await runLinearSteps(
+            compiled,
+            ctx,
+            run.id,
+            runLog,
+            key,
+            owner,
+            depth,
+          );
         }
         await store.finishRun(run.id, "success", ctx);
         return { runId: run.id, status: "success", result: ctx };
@@ -347,6 +486,16 @@ export function createRegistry(server) {
           error: err instanceof Error ? err.message : String(err),
         };
       }
+    };
+
+    if (detach) {
+      execute().catch((err) => {
+        runLog.error({ err }, "detached workflow failed unexpectedly");
+      });
+      return { runId: run.id, status: "started" };
+    }
+
+    return execute();
   }
 
   function reregister() {

packages/server/script-sandbox.js

@@ -317,10 +317,28 @@ function createSecretsApi(owner) {
   };
 }
 
+const $workflowsStub = {
+  async trigger() {
+    throw new Error("workflow runner is not available");
+  },
+};
+
 /**
- * @param {{ log: import("pino").Logger, script: string, workflowName: string, owner?: string }} opts
+ * @param {{
+ *   log: import("pino").Logger,
+ *   script: string,
+ *   workflowName: string,
+ *   owner?: string,
+ *   $workflows?: { trigger: (name: string, data?: unknown) => Promise<unknown> },
+ * }} opts
  */
-function createScriptSandbox({ log, script, workflowName, owner = "default" }) {
+function createScriptSandbox({
+  log,
+  script,
+  workflowName,
+  owner = "default",
+  $workflows = $workflowsStub,
+}) {
   const scriptLog = log.child({ workflow: workflowName, script });
   const $axios = createScreenedAxios(scriptLog);
   const $kv = createKvApi(workflowName);
@@ -332,6 +350,7 @@ function createScriptSandbox({ log, script, workflowName, owner = "default" }) {
     $axios,
     $kv,
     $secrets,
+    $workflows,
     require: createRestrictedRequire($axios),
   };
 
@@ -376,10 +395,16 @@ export function extractScriptMeta(fn) {
 
 /**
  * @param {import("node:vm").Script} compiled
- * @param {{ log: import("pino").Logger, script: string, workflowName: string, owner?: string }} opts
+ * @param {{
+ *   log: import("pino").Logger,
+ *   script: string,
+ *   workflowName: string,
+ *   owner?: string,
+ *   $workflows?: { trigger: (name: string, data?: unknown) => Promise<unknown> },
+ * }} opts
  */
-function instantiateCompiled(compiled, { log, script, workflowName, owner }) {
+function instantiateCompiled(compiled, { log, script, workflowName, owner, $workflows }) {
-  const sandbox = createScriptSandbox({ log, script, workflowName, owner });
+  const sandbox = createScriptSandbox({ log, script, workflowName, owner, $workflows });
   return compiled.runInContext(sandbox);
 }
 
@@ -389,7 +414,12 @@ function instantiateCompiled(compiled, { log, script, workflowName, owner }) {
  *
  * @param {string} script
  * @param {string} source
- * @param {{ log?: import("pino").Logger, workflowName?: string, owner?: string }} [opts]
+ * @param {{
+ *   log?: import("pino").Logger,
+ *   workflowName?: string,
+ *   owner?: string,
+ *   $workflows?: { trigger: (name: string, data?: unknown) => Promise<unknown> },
+ * }} [opts]
  */
 export function instantiateScriptSource(script, source, opts = {}) {
   const compiled = compileScriptSource(source, script);
@@ -398,6 +428,7 @@ export function instantiateScriptSource(script, source, opts = {}) {
     script,
     workflowName: opts.workflowName ?? "inspect",
     owner: opts.owner ?? "default",
+    $workflows: opts.$workflows,
   });
   return { fn, ...extractScriptMeta(fn) };
 }
@@ -439,11 +470,22 @@ function loadCompiledScript(script) {
  *
  * @param {string} script
  * @param {unknown} ctx
- * @param {{ log: import("pino").Logger, workflowName: string, owner?: string }} opts
+ * @param {{
+ *   log: import("pino").Logger,
+ *   workflowName: string,
+ *   owner?: string,
+ *   $workflows?: { trigger: (name: string, data?: unknown) => Promise<unknown> },
+ * }} opts
  */
-export async function runScript(script, ctx, { log, workflowName, owner }) {
+export async function runScript(script, ctx, { log, workflowName, owner, $workflows }) {
   const compiled = loadCompiledScript(script);
-  const fn = instantiateCompiled(compiled, { log, script, workflowName, owner });
+  const fn = instantiateCompiled(compiled, {
+    log,
+    script,
+    workflowName,
+    owner,
+    $workflows,
+  });
   return await fn(ctx);
 }
 
@@ -453,9 +495,19 @@ export async function runScript(script, ctx, { log, workflowName, owner }) {
  * @param {string} script
  * @param {string} source
  * @param {unknown} ctx
- * @param {{ log: import("pino").Logger, workflowName: string, owner?: string }} opts
+ * @param {{
+ *   log: import("pino").Logger,
+ *   workflowName: string,
+ *   owner?: string,
+ *   $workflows?: { trigger: (name: string, data?: unknown) => Promise<unknown> },
+ * }} opts
  */
-export async function runScriptSource(script, source, ctx, { log, workflowName, owner }) {
+export async function runScriptSource(script, source, ctx, { log, workflowName, owner, $workflows }) {
-  const { fn } = instantiateScriptSource(script, source, { log, workflowName, owner });
+  const { fn } = instantiateScriptSource(script, source, {
+    log,
+    workflowName,
+    owner,
+    $workflows,
+  });
   return await fn(ctx);
 }

packages/server/scripts/trigger-workflow.js

@@ -0,0 +1,64 @@
+import jsonata from "jsonata";
+
+async function triggerWorkflow(ctx) {
+  const name = ctx.config?.name;
+  if (typeof name !== "string" || name.length === 0) {
+    throw new Error("config.name is required");
+  }
+
+  let data = ctx.data;
+  const expression = ctx.config?.expression;
+  if (typeof expression === "string" && expression.length > 0) {
+    const result = jsonata(expression).evaluate(ctx.data);
+    data = await result;
+  }
+
+  const started = await $workflows.trigger(name, data);
+  const triggered = { name, runId: started?.runId ?? null };
+
+  const base =
+    ctx != null && typeof ctx === "object" && !Array.isArray(ctx) ? { ...ctx } : {};
+
+  if (base.data != null && typeof base.data === "object" && !Array.isArray(base.data)) {
+    return { ...base, data: { ...base.data, triggered } };
+  }
+  return { ...base, triggered };
+}
+
+triggerWorkflow.meta = {
+  description:
+    "Fire-and-forget another workflow by YAML name (same owner). Destination must declare triggers: [{ type: workflow }]. Optionally reshape ctx.data with JSONata before sending.",
+  config: {
+    name: {
+      type: "string",
+      required: true,
+      description: "Destination workflow YAML name (same owner)",
+    },
+    expression: {
+      type: "string",
+      required: false,
+      description:
+        "Optional JSONata expression evaluated against ctx.data; result becomes the destination run input",
+    },
+  },
+  input: {},
+  output: {
+    triggered: {
+      type: "object",
+      description: "Record of the kicked-off run ({ name, runId }); under data when data is an object",
+    },
+  },
+  example: {
+    data: {
+      title: "Hello",
+      url: "https://example.com/img.png",
+    },
+    config: {
+      name: "notify-comic",
+      expression:
+        '{ "title": title, "message": title, "attach": url }',
+    },
+  },
+};
+
+export default triggerWorkflow;

packages/web/src/lib/workflow-mermaid.js

@@ -47,6 +47,7 @@ function mermaidLabel(text) {
 function triggerLabel(t) {
   const type = String(t?.type ?? "").toLowerCase();
   if (type === "cron") return `cron ${t.schedule ?? ""}`.trim();
+  if (type === "workflow") return "workflow";
   const method = t?.method ?? "POST";
   const path = t?.path ?? "";
   return `${method} ${path}`.trim();

packages/web/src/pages/WorkflowsPage.jsx

@@ -211,12 +211,14 @@ function triggerLabel(t) {
   const type = String(t?.type ?? "").toLowerCase();
   if (type === "cron") return t.schedule || "cron";
   if (type === "http") return t.path || "/";
+  if (type === "workflow") return "";
   return t?.type ?? "—";
 }
 
 function triggerKind(t) {
   const type = String(t?.type ?? "").toLowerCase();
   if (type === "http") return t.method || "POST";
+  if (type === "workflow") return "workflow";
   return t?.type ?? "—";
 }