1 files changed, 137 insertions, 0 deletions
diff --git a/src/config.ts b/src/config.ts
new file mode 100644
index 0000000..e836552
--- /dev/null
+++ b/src/config.ts
@@ -0,0 +1,137 @@
+import winston from "winston";
+import { MongoClient, MongoError } from "mongodb";
+import { Server } from "http";
+import path from "path";
+import fs from "fs";
+import { v4 as uuid } from "uuid";
+
+import processTemplate, { Template } from "./templates";
+import { EnvConfig } from "./metadata";
+
+/**
+ * Generate a token for use as the user self-identifier
+ */
+export const initializeToken = (logger: winston.Logger): string => {
+  //TODO check for token in hostDir/persist created token in hostDir so it's not regenerated on startup
+  const newToken = uuid();
+
+  logger.warn(
+    "TOKEN variable not provided, using this value instead: %s",
+    newToken
+  );
+  logger.warn(
+    "Use this provided token to push your coverage reports to the server."
+  );
+
+  return newToken;
+};
+
+/**
+ * Get environment variable or exit application if it doesn't exist
+ */
+export const configOrError = (varName: string, logger: winston.Logger): string => {
+  const value = process.env[varName];
+  if (value !== undefined) {
+    return value;
+  } else {
+    logger.error("%s must be defined", varName);
+    process.exit(1);
+  }
+};
+
+/**
+ * Process a template and persist based on template.
+ */
+export const persistTemplate = async (input: Template, logger: winston.Logger): Promise<void> => {
+  try {
+    const template = await processTemplate(input);
+    logger.debug("Generated '%s' from template file", template.outputFile);
+  } catch (err1) {
+    try {
+      await fs.promises.access(input.outputFile, fs.constants.R_OK);
+    } catch (err2) {
+      logger.error(
+        "Error while generating '%s' from template file: %s",
+        input.outputFile,
+        err1
+      );
+      logger.error("Cannot proceed due to error: %s", err2);
+
+      process.exit(1);
+    }
+    // if the output file exists, then we are fine with continuing without
+    logger.warn(
+      "Could not generate '%s' from template file, but file already exists: %s",
+      input.outputFile,
+      err1
+    );
+  }
+};
+
+/**
+ * Handle server start-up functions:
+ * 
+ * - Open database connection
+ * - Generate documents from templates based on configuration
+ * 
+ * If one of these actions cannot be performed, it will call `process.exit(1)`.
+ */
+export const handleStartup = async (config: EnvConfig, logger: winston.Logger): Promise<MongoClient> => {
+  try {
+    const { hostDir, publicDir, dbUri, targetUrl } = config;
+    await fs.promises.access(hostDir, fs.constants.R_OK | fs.constants.W_OK);
+    if (!path.isAbsolute(hostDir)) {
+      await Promise.reject("hostDir must be an absolute path");
+    }
+
+    const mongo = await MongoClient.connect(dbUri).catch((err: MongoError) =>
+      Promise.reject(err.message ?? "Unable to connect to database")
+    );
+
+    await persistTemplate({
+      inputFile: path.join(publicDir, "templates", "sh.tmpl"),
+      outputFile: path.join(hostDir, "sh"),
+      context: { TARGET_URL: targetUrl },
+    } as Template, logger);
+    await persistTemplate({
+      inputFile: path.join(publicDir, "templates", "index.html.tmpl"),
+      outputFile: path.join(hostDir, "index.html"),
+      context: {
+        TARGET_URL: targetUrl,
+        CURL_HTTPS: targetUrl.includes("https")
+          ? "--proto '=https' --tlsv1.2 "
+          : "",
+      },
+    } as Template, logger);
+
+    return mongo;
+  } catch (err) {
+    logger.error("Error occurred during startup: %s", err);
+    process.exit(1);
+  }
+};
+
+/**
+ * Callback for NodeJS `process.on()` to handle shutdown signals
+ * and close open connections.
+ */
+export const handleShutdown =
+  (mongo: MongoClient, server: Server, logger: winston.Logger) =>
+  async (signal: NodeJS.Signals): Promise<void> => {
+    logger.warn("%s signal received. Closing shop.", signal);
+
+    try {
+      await mongo.close();
+      logger.info("MongoDB client connection closed.");
+
+      // must await for callback - wrapped in Promise
+      await new Promise((res, rej) => server.close((err) => {
+        logger.info("Express down.");
+        (err ? rej : res)(err);
+      }));
+
+      process.exit(0);
+    } catch (e) {
+      process.exit(1);
+    }
+  };