Add winston, express-winston to handle logging

2 files changed, 59 insertions, 0 deletions

diff --git a/src/util/config.ts b/src/util/config.ts
new file mode 100644
index 0000000..c155e64
--- /dev/null
+++ b/src/util/config.ts
@@ -0,0 +1,38 @@
+import winston from "winston";
+import { MongoClient } from "mongodb";
+import { Server } from "http";
+
+import logger_config from "./logger";
+
+const logger = winston.createLogger(logger_config("ROOT"));
+
+export const config_or_error = (var_name: string) => {
+  if (!process.env[var_name]) {
+    logger.error("%s must be defined", var_name);
+    process.exit(1);
+    return "";
+  } else {
+    return process.env[var_name] || "";
+  }
+};
+
+export const handle_shutdown = (mongo: MongoClient, server: Server) => (
+  signal: NodeJS.Signals
+) => {
+  logger.warn("%s signal received. Closing shop.", signal);
+
+  mongo
+    .close()
+    .then(() => {
+      logger.info("MongoDB client connection closed.");
+      return new Promise((res, rej) =>
+        server.close(err => {
+          logger.info("Express down.");
+          (err ? rej : res)(err);
+        })
+      );
+    })
+    .finally(() => {
+      process.exit(0);
+    });
+};
diff --git a/src/util/logger.ts b/src/util/logger.ts
new file mode 100644
index 0000000..bafb829
--- /dev/null
+++ b/src/util/logger.ts
@@ -0,0 +1,21 @@
+import winston from "winston";
+const { combine, splat, timestamp, label, colorize, printf } = winston.format;
+const { Console } = winston.transports;
+
+const LOG_LEVEL = process.env.LOG_LEVEL || "info";
+
+/**
+ * Provides standard logging format and output for the server.
+ */
+export default (clazz: string, level: string = LOG_LEVEL) => ({
+  format: combine(
+    splat(),
+    timestamp(),
+    label({ label: clazz }),
+    colorize(),
+    printf(({ level, message, label, timestamp }) => {
+      return `${timestamp} [${label}] ${level}: ${message}`;
+    })
+  ),
+  transports: [new Console({ level: level })]
+});