feat(price-pusher): allow mnemonic from MNEMONIC env var

apps/price_pusher/README.md

@@ -83,6 +83,8 @@ Pyth hosts [public endpoints](https://docs.pyth.network/price-feeds/api-instance
 Hermes RPC providers for more reliability. Please refer to [this
 document](https://docs.pyth.network/documentation/pythnet-price-feeds/hermes) for more information.
 
+The signing mnemonic can be supplied via either the `--mnemonic-file` flag (path to a file containing the mnemonic) or the `MNEMONIC` environment variable. The environment variable is convenient for platforms that inject secrets as encrypted env vars (e.g. DigitalOcean, Fly.io). If both are supplied, `--mnemonic-file` takes precedence.
+
 To run the price pusher, please run the following commands, replacing the command line arguments as necessary:
 
 ```sh

apps/price_pusher/package.json

@@ -215,9 +215,10 @@
     "dev": "ts-node src/index.ts",
     "prepublishOnly": "pnpm run build",
     "start": "node dist/index.cjs",
-    "test:types": "tsc"
+    "test:types": "tsc",
+    "test:unit": "test-unit"
   },
   "type": "module",
   "types": "./dist/index.d.ts",
-  "version": "10.4.0"
+  "version": "10.5.0"
 }

apps/price_pusher/src/aptos/command.ts

@@ -3,8 +3,6 @@
 /* eslint-disable @typescript-eslint/no-unsafe-argument */
 /* eslint-disable @typescript-eslint/no-unsafe-assignment */
 /* eslint-disable @typescript-eslint/no-explicit-any */
-import fs from "node:fs";
-
 import { HermesClient } from "@pythnetwork/hermes-client";
 import { AptosAccount } from "aptos";
 import pino from "pino";
@@ -15,7 +13,7 @@ import { PricePusherMetrics } from "../metrics.js";
 import * as options from "../options.js";
 import { readPriceConfigFile } from "../price-config.js";
 import { PythPriceListener } from "../pyth-price-listener.js";
-import { filterInvalidPriceItems } from "../utils.js";
+import { filterInvalidPriceItems, readMnemonic } from "../utils.js";
 import {
   APTOS_ACCOUNT_HD_PATH,
   AptosPriceListener,
@@ -87,7 +85,7 @@ export default {
       logger.info(`Metrics server started on port ${metricsPort}`);
     }
 
-    const mnemonic = fs.readFileSync(mnemonicFile, "utf8").trim();
+    const mnemonic = readMnemonic(mnemonicFile);
     const account = AptosAccount.fromDerivePath(
       APTOS_ACCOUNT_HD_PATH,
       mnemonic,

apps/price_pusher/src/evm/command.ts

@@ -3,8 +3,6 @@
 /* eslint-disable @typescript-eslint/no-unsafe-argument */
 /* eslint-disable @typescript-eslint/no-unsafe-assignment */
 /* eslint-disable @typescript-eslint/no-explicit-any */
-import fs from "node:fs";
-
 import { HermesClient } from "@pythnetwork/hermes-client";
 import pino from "pino";
 import type { Options } from "yargs";
@@ -14,7 +12,11 @@ import { PricePusherMetrics } from "../metrics.js";
 import * as options from "../options.js";
 import { readPriceConfigFile } from "../price-config.js";
 import { PythPriceListener } from "../pyth-price-listener.js";
-import { filterInvalidPriceItems, isWsEndpoint } from "../utils.js";
+import {
+  filterInvalidPriceItems,
+  isWsEndpoint,
+  readMnemonic,
+} from "../utils.js";
 import { createEvmBalanceTracker } from "./balance-tracker.js";
 import { getCustomGasStation } from "./custom-gas-station.js";
 import { EvmPriceListener, EvmPricePusher } from "./evm.js";
@@ -129,7 +131,7 @@ export default {
       accessToken: hermesAccessToken,
     });
 
-    const mnemonic = fs.readFileSync(mnemonicFile, "utf8").trim();
+    const mnemonic = readMnemonic(mnemonicFile);
 
     let priceItems = priceConfigs.map(({ id, alias }) => ({ alias, id }));
 

apps/price_pusher/src/injective/command.ts

@@ -1,8 +1,6 @@
 /* eslint-disable @typescript-eslint/no-unsafe-argument */
 /* eslint-disable @typescript-eslint/no-unsafe-assignment */
 /* eslint-disable @typescript-eslint/no-explicit-any */
-import fs from "node:fs";
-
 import { getNetworkInfo } from "@injectivelabs/networks";
 import { HermesClient } from "@pythnetwork/hermes-client";
 import { pino } from "pino";
@@ -11,7 +9,7 @@ import { Controller } from "../controller.js";
 import * as options from "../options.js";
 import { readPriceConfigFile } from "../price-config.js";
 import { PythPriceListener } from "../pyth-price-listener.js";
-import { filterInvalidPriceItems } from "../utils.js";
+import { filterInvalidPriceItems, readMnemonic } from "../utils.js";
 import { InjectivePriceListener, InjectivePricePusher } from "./injective.js";
 export default {
   builder: {
@@ -83,7 +81,7 @@ export default {
     const hermesClient = new HermesClient(priceServiceEndpoint, {
       accessToken: hermesAccessToken,
     });
-    const mnemonic = fs.readFileSync(mnemonicFile, "utf8").trim();
+    const mnemonic = readMnemonic(mnemonicFile);
 
     let priceItems = priceConfigs.map(({ id, alias }) => ({ alias, id }));
 

apps/price_pusher/src/options.ts

@@ -60,9 +60,11 @@ export const pushingFrequency = {
 
 export const mnemonicFile = {
   "mnemonic-file": {
-    description: "Path to payer mnemonic (private key) file.",
-    required: true,
+    description:
+      "Path to payer mnemonic (private key) file. " +
+      "If omitted, the mnemonic is read from the `MNEMONIC` environment variable.",
     type: "string",
+    required: false,
   } as Options,
 };
 

apps/price_pusher/src/sui/command.ts

@@ -3,8 +3,6 @@
 /* eslint-disable @typescript-eslint/no-unsafe-argument */
 /* eslint-disable @typescript-eslint/no-unsafe-assignment */
 /* eslint-disable @typescript-eslint/no-explicit-any */
-import fs from "node:fs";
-
 import { SuiClient } from "@mysten/sui/client";
 import { Ed25519Keypair } from "@mysten/sui/keypairs/ed25519";
 import { HermesClient } from "@pythnetwork/hermes-client";
@@ -16,7 +14,7 @@ import { PricePusherMetrics } from "../metrics.js";
 import * as options from "../options.js";
 import { readPriceConfigFile } from "../price-config";
 import { PythPriceListener } from "../pyth-price-listener.js";
-import { filterInvalidPriceItems } from "../utils.js";
+import { filterInvalidPriceItems, readMnemonic } from "../utils.js";
 import { createSuiBalanceTracker } from "./balance-tracker.js";
 import { SuiPriceListener, SuiPricePusher } from "./sui.js";
 
@@ -114,7 +112,7 @@ export default {
       accessToken: hermesAccessToken,
     });
 
-    const mnemonic = fs.readFileSync(mnemonicFile, "utf8").trim();
+    const mnemonic = readMnemonic(mnemonicFile);
     const keypair = Ed25519Keypair.deriveKeypair(
       mnemonic,
       `m/44'/784'/${accountIndex}'/0'/0'`,

apps/price_pusher/src/utils.ts

@@ -1,6 +1,8 @@
 /* eslint-disable @typescript-eslint/no-unsafe-return */
 /* eslint-disable @typescript-eslint/no-unnecessary-type-parameters */
 /* eslint-disable @typescript-eslint/no-explicit-any */
+import fs from "node:fs";
+
 import type { HermesClient, HexString } from "@pythnetwork/hermes-client";
 
 import type { PriceItem } from "./interface.js";
@@ -60,6 +62,21 @@ export const assertDefined = <T>(value: T | undefined): T => {
   }
 };
 
+export function readMnemonic(mnemonicFile: string | undefined): string {
+  if (mnemonicFile !== undefined && mnemonicFile !== "") {
+    return fs.readFileSync(mnemonicFile, "utf8").trim();
+  }
+
+  const envMnemonic = process.env.MNEMONIC;
+  if (envMnemonic !== undefined && envMnemonic !== "") {
+    return envMnemonic.trim();
+  }
+
+  throw new Error(
+    "No mnemonic provided. Pass --mnemonic-file or set the MNEMONIC environment variable.",
+  );
+}
+
 export async function filterInvalidPriceItems(
   hermesClient: HermesClient,
   priceItems: PriceItem[],

apps/price_pusher/tests/utils.test.ts

@@ -0,0 +1,62 @@
+// biome-ignore-all lint/style/noProcessEnv: test file manipulates env vars
+
+import { mkdtempSync, rmSync, writeFileSync } from "node:fs";
+import { tmpdir } from "node:os";
+import { join } from "node:path";
+
+import { readMnemonic } from "../src/utils.js";
+
+describe("readMnemonic", () => {
+  let tmpDir: string;
+  const originalMnemonic = process.env.MNEMONIC;
+
+  beforeEach(() => {
+    tmpDir = mkdtempSync(join(tmpdir(), "price-pusher-test-"));
+    delete process.env.MNEMONIC;
+  });
+
+  afterEach(() => {
+    rmSync(tmpDir, { recursive: true, force: true });
+    if (originalMnemonic === undefined) {
+      delete process.env.MNEMONIC;
+    } else {
+      process.env.MNEMONIC = originalMnemonic;
+    }
+  });
+
+  it("reads mnemonic from file when path supplied", () => {
+    const path = join(tmpDir, "mnemonic");
+    writeFileSync(path, "from file mnemonic\n");
+    expect(readMnemonic(path)).toBe("from file mnemonic");
+  });
+
+  it("falls back to MNEMONIC env var when no file path supplied", () => {
+    process.env.MNEMONIC = "from env mnemonic";
+    expect(readMnemonic(undefined)).toBe("from env mnemonic");
+  });
+
+  it("treats empty-string file path as not supplied", () => {
+    process.env.MNEMONIC = "from env mnemonic";
+    expect(readMnemonic("")).toBe("from env mnemonic");
+  });
+
+  it("file source takes precedence over env var", () => {
+    const path = join(tmpDir, "mnemonic");
+    writeFileSync(path, "from file\n");
+    process.env.MNEMONIC = "from env";
+    expect(readMnemonic(path)).toBe("from file");
+  });
+
+  it("throws when neither file nor env var supplied", () => {
+    expect(() => readMnemonic(undefined)).toThrow(
+      /No mnemonic provided/,
+    );
+  });
+
+  it("throws when env var is empty string", () => {
+    process.env.MNEMONIC = "";
+    expect(() => readMnemonic(undefined)).toThrow(
+      /No mnemonic provided/,
+    );
+  });
+});