feat: add rollback_on_failure feature (#88)

This PR adds the ability to download existing code before deployment and automatically roll back if the post-deployment monitor detects a failure.

Reviewed-on: #88
Reviewed-by: LLMReview <27+autoreview@noreplay.horstenkamp.eu>

GEMINI.md

@@ -6,6 +6,7 @@ This repository is maintained by Gemini.
 
 *   **Test-Driven Development (TDD):** Wherever possible, Test-Driven Development principles should be followed. Write tests before writing the code they are intended to validate.
 *   **Pre-commit Hooks:** Ensure that `pre-commit` hooks are installed and active before making any commits. This can be done by running `pre-commit install` in your local repository.
+    *   **Note for Gemini:** Git commits trigger pre-commit hooks, which can take several seconds (or minutes) to complete. Checking the command status for git commit is only appropriate every 120s.
 
 ## Repository Comparison
 

__tests__/index.test.js

@@ -20,6 +20,23 @@ vi.mock("../monitor.js", () => ({
   }),
 }));
 
+// Mock screeps-api
+vi.mock("screeps-api", () => {
+  const mockApi = {
+    auth: vi.fn().mockResolvedValue(),
+    code: {
+      get: vi.fn().mockResolvedValue({ ok: 1, modules: { main: "old_code" } }),
+      set: vi.fn().mockResolvedValue({ ok: 1 }),
+    },
+  };
+  // Use a regular function so it can be called with `new`
+  return {
+    ScreepsAPI: vi.fn(function () {
+      return mockApi;
+    }),
+  };
+});
+
 import * as core from "@actions/core";
 import { monitorConsole } from "../monitor.js";
 
@@ -29,7 +46,9 @@ import {
   readReplaceAndWriteFiles,
   readFilesIntoDict,
   applyOnAction,
+  postCode,
 } from "../index.js";
+import { ScreepsAPI } from "screeps-api";
 import fs from "fs";
 import path from "path";
 import os from "os";
@@ -231,31 +250,31 @@ describe("glob functionality", () => {
 describe("applyOnAction", () => {
   beforeEach(() => vi.clearAllMocks());
 
-  it("'ignore' + true → no core call", () => {
+  it("'ignore' + true → no core call, returns false", () => {
-    applyOnAction("ignore", true, "msg");
+    expect(applyOnAction("ignore", true, "msg")).toBe(false);
     expect(core.warning).not.toHaveBeenCalled();
     expect(core.setFailed).not.toHaveBeenCalled();
   });
 
-  it("'warn' + true → core.warning() called with message", () => {
+  it("'warn' + true → core.warning() called with message, returns false", () => {
-    applyOnAction("warn", true, "boom");
+    expect(applyOnAction("warn", true, "boom")).toBe(false);
     expect(core.warning).toHaveBeenCalledWith("boom");
     expect(core.setFailed).not.toHaveBeenCalled();
   });
 
-  it("'fail' + true → core.setFailed() called with message", () => {
+  it("'fail' + true → core.setFailed() called with message, returns true", () => {
-    applyOnAction("fail", true, "boom");
+    expect(applyOnAction("fail", true, "boom")).toBe(true);
     expect(core.setFailed).toHaveBeenCalledWith("boom");
     expect(core.warning).not.toHaveBeenCalled();
   });
 
-  it("'fail' + false → no core call", () => {
+  it("'fail' + false → no core call, returns false", () => {
-    applyOnAction("fail", false, "boom");
+    expect(applyOnAction("fail", false, "boom")).toBe(false);
     expect(core.setFailed).not.toHaveBeenCalled();
   });
 
-  it("'warn' + false → no core call", () => {
+  it("'warn' + false → no core call, returns false", () => {
-    applyOnAction("warn", false, "msg");
+    expect(applyOnAction("warn", false, "msg")).toBe(false);
     expect(core.warning).not.toHaveBeenCalled();
   });
 });
@@ -270,28 +289,60 @@ describe("postCode — monitor wiring", () => {
     // Default core mocks
     core.getInput.mockImplementation((name) => {
       if (name === "monitor") return "0";
+      if (name === "token") return "test-token";
+      if (name === "branch") return "default";
+      if (name === "on_traceback") return "fail";
       return "";
     });
-    core.getBooleanInput.mockReturnValue(false);
+    core.getBooleanInput.mockImplementation((name) => {
+      if (name === "rollback_on_failure") return false;
+      return false;
+    });
   });
 
   it("does not call monitorConsole when monitor=0 (default)", async () => {
-    // We need to mock the rest of postCode to not fail before it hits the monitor block
+    // We just run postCode with monitor=0 and verify monitorConsole is not called.
-    // This is a bit complex as postCode is large, but we can mock the inputs to exit early or mock the API
+    await postCode();
-    // Actually, I'll just check if monitorConsole is called.
+    expect(monitorConsole).not.toHaveBeenCalled();
+  });
 
-    // For this test, I'll make validateAuthentication fail so it returns early but after input check
+  it("rolls back to previous code when monitor detects a failure and rollback_on_failure is true", async () => {
+    // Setup inputs for monitor and rollback
     core.getInput.mockImplementation((name) => {
-      if (name === "monitor") return "0";
+      if (name === "monitor") return "10";
+      if (name === "token") return "test-token";
+      if (name === "branch") return "default";
+      if (name === "on_traceback") return "fail";
       return "";
     });
+    core.getBooleanInput.mockImplementation((name) => {
+      if (name === "rollback_on_failure") return true;
+      return false;
+    });
 
-    // We'll just run a partial check or rely on the monitor unit tests for depth
+    // Simulate a failure in monitorConsole
-    // The wiring in index.js is:
+    monitorConsole.mockResolvedValueOnce({
-    // const monitorTicks = parseInt(core.getInput("monitor") || "0", 10);
+      sawTraceback: true, // Should trigger "fail" due to on_traceback=fail
-    // if (monitorTicks > 0) { ... }
+      sawErrorLog: false,
+      sawWarningLog: false,
+    });
 
-    // Testing the logic inside index.js directly by calling postCode would require full environment mock.
+    await postCode();
-    // I'll stick to the applyOnAction unit tests and rely on monitor.test.js for the heavy lifting.
+
+    // Verify rollback was performed
+    const mockApiInstance = new ScreepsAPI();
+
+    // `code.set` should be called twice:
+    // 1st time: uploading the new files
+    // 2nd time: rolling back to oldCode
+    expect(mockApiInstance.code.set).toHaveBeenCalledTimes(2);
+    expect(mockApiInstance.code.set).toHaveBeenNthCalledWith(2, "default", {
+      main: "old_code",
+    });
+
+    // Verify it called core.setFailed due to traceback
+    expect(core.setFailed).toHaveBeenCalledWith(
+      "Screeps console: traceback detected",
+    );
   });
 });

action.yaml

@@ -67,6 +67,10 @@ inputs:
     description: 'Print a progress update every N ticks when log_to_file=true (default: 10).'
     required: false
     default: '10'
+  rollback_on_failure:
+    description: 'Automatically rollback to previous code if the monitor detects failures. Requires monitor > 0. (default: false)'
+    required: false
+    default: 'false'
 outputs:
   saw_traceback:
     description: true if a JS traceback was detected during monitoring.

index.js

@@ -118,17 +118,19 @@ export function validateAuthentication(token, username, password) {
  * @param {'ignore'|'warn'|'fail'} action
  * @param {boolean} flag    - Only acts when true
  * @param {string}  message - Passed to core.warning / core.setFailed
+ * @returns {boolean} - Returns true if the action was 'fail' and the flag was true.
  */
 export function applyOnAction(action, flag, message) {
-  if (!flag) return;
+  if (!flag) return false;
   if (action === "warn") {
     core.warning(message);
-    return;
+    return false;
   }
   if (action === "fail") {
     core.setFailed(message);
+    return true;
   }
-  // 'ignore' → no-op
+  return false;
 }
 
 /**
@@ -179,33 +181,72 @@ export async function postCode() {
     return;
   }
   let api = new ScreepsAPI(login_arguments);
-  if (token) {
+
+  if (!token) {
+    core.info(`Logging in as user ${username}`);
+    try {
+      await api.auth(username, password, login_arguments);
+    } catch (err) {
+      core.error(`Authentication error: ${err}`);
+      throw err;
+    }
+  }
+
+  let oldCode = null;
+  let rollbackOnFailure = false;
+  try {
+    rollbackOnFailure = core.getBooleanInput("rollback_on_failure");
+  } catch (e) {
+    // getBooleanInput throws if not 'true' or 'false', ignore
+  }
+
+  if (rollbackOnFailure) {
+    core.info(
+      `Downloading existing code from branch ${branch} for potential rollback...`,
+    );
+    try {
+      const getResponse = await api.code.get(branch);
+      if (getResponse && getResponse.ok && getResponse.modules) {
+        oldCode = getResponse.modules;
+        core.info(
+          `Successfully downloaded existing code (modules: ${Object.keys(oldCode).join(", ")})`,
+        );
+      } else {
+        core.setFailed(
+          `Failed to download existing code, but rollback_on_failure is enabled. Aborting deployment.`,
+        );
+        return;
+      }
+    } catch (err) {
+      core.setFailed(
+        `Error downloading existing code: ${err.message}. Aborting deployment.`,
+      );
+      return;
+    }
+  }
+
+  try {
     const response = await api.code.set(branch, files_to_push);
     core.info(JSON.stringify(response, null, 2));
     core.info(`Code set successfully to ${branch}`);
-  } else {
+  } catch (err) {
-    core.info(`Logging in as user ${username}`);
-    await Promise.resolve()
-      .then(() => api.auth(username, password, login_arguments))
-      .then(() => api.code.set(branch, files_to_push))
-      .then(() => {
-        core.info(`Code set successfully to ${branch}`);
-      })
-      .catch((err) => {
     core.error(`Upload error: ${err}`);
     throw err;
-      });
   }
 
   // Console monitoring (optional)
   const monitorTicks = parseInt(core.getInput("monitor") || "0", 10);
   if (monitorTicks > 0) {
+    const onTraceback = core.getInput("on_traceback") || "fail";
+    const onErrorLog = core.getInput("on_error_log") || "warn";
+    const onWarningLog = core.getInput("on_warning_log") || "ignore";
+
     const result = await monitorConsole(api, {
       monitor: monitorTicks,
       logToFile: core.getBooleanInput("log_to_file"),
-      onTraceback: core.getInput("on_traceback") || "fail",
+      onTraceback,
-      onErrorLog: core.getInput("on_error_log") || "warn",
+      onErrorLog,
-      onWarningLog: core.getInput("on_warning_log") || "ignore",
+      onWarningLog,
       monitorInterval: parseInt(core.getInput("monitor_interval") || "10", 10),
       hostname,
       shard: core.getInput("shard") || undefined,
@@ -215,21 +256,37 @@ export async function postCode() {
     core.setOutput("saw_error_log", String(result.sawErrorLog));
     core.setOutput("saw_warning_log", String(result.sawWarningLog));
 
-    applyOnAction(
+    const fail1 = applyOnAction(
-      core.getInput("on_traceback"),
+      onTraceback,
       result.sawTraceback,
       "Screeps console: traceback detected",
     );
-    applyOnAction(
+    const fail2 = applyOnAction(
-      core.getInput("on_error_log"),
+      onErrorLog,
       result.sawErrorLog,
       "Screeps console: error log output detected",
     );
-    applyOnAction(
+    const fail3 = applyOnAction(
-      core.getInput("on_warning_log"),
+      onWarningLog,
       result.sawWarningLog,
       "Screeps console: warning log output detected",
     );
+
+    const shouldFail = fail1 || fail2 || fail3;
+
+    if (shouldFail && rollbackOnFailure && oldCode) {
+      core.info(
+        "Action failed based on monitor configuration. Rolling back to previous code...",
+      );
+      try {
+        await api.code.set(branch, oldCode);
+        core.info(
+          `Successfully rolled back to previous code on branch ${branch}.`,
+        );
+      } catch (err) {
+        core.error(`Rollback failed: ${err}`);
+      }
+    }
   }
 }