add debug messages for environment variables and show exports in .env…

….example so users can more easily run datagen from a different directory from the .env file (#102)

.env.example

@@ -1,20 +1,20 @@
 # Kafka
-KAFKA_BROKERS=
+export KAFKA_BROKERS=
 
 # Kafka SASL Authentication
-SASL_USERNAME=
-SASL_PASSWORD=
-SASL_MECHANISM=
+export SASL_USERNAME=
+export SASL_PASSWORD=
+export SASL_MECHANISM=
 
 # Kafka SSL Authentication
-SSL_CA_LOCATION=
-SSL_CERT_LOCATION=
-SSL_KEY_LOCATION=
+export SSL_CA_LOCATION=
+export SSL_CERT_LOCATION=
+export SSL_KEY_LOCATION=
 
 # Schema Registry if producing Avro
-SCHEMA_REGISTRY_URL=
-SCHEMA_REGISTRY_USERNAME=
-SCHEMA_REGISTRY_PASSWORD=
+export SCHEMA_REGISTRY_URL=
+export SCHEMA_REGISTRY_USERNAME=
+export SCHEMA_REGISTRY_PASSWORD=
 
 # Postgres
 export POSTGRES_HOST=

README.md

@@ -42,32 +42,33 @@ Create a file called `.env` with the following environment variables
 
 ```bash
 # Kafka Brokers
-KAFKA_BROKERS=
+export KAFKA_BROKERS=
 
 # For Kafka SASL Authentication:
-SASL_USERNAME=
-SASL_PASSWORD=
-SASL_MECHANISM=
+export SASL_USERNAME=
+export SASL_PASSWORD=
+export SASL_MECHANISM=
 
 # For Kafka SSL Authentication:
-SSL_CA_LOCATION=
-SSL_CERT_LOCATION=
-SSL_KEY_LOCATION=
+export SSL_CA_LOCATION=
+export SSL_CERT_LOCATION=
+export SSL_KEY_LOCATION=
 
 # Connect to Schema Registry if using '--format avro'
-SCHEMA_REGISTRY_URL=
-SCHEMA_REGISTRY_USERNAME=
-SCHEMA_REGISTRY_PASSWORD=
+export SCHEMA_REGISTRY_URL=
+export SCHEMA_REGISTRY_USERNAME=
+export SCHEMA_REGISTRY_PASSWORD=
 
 # Postgres
-POSTGRES_HOST=
-POSTGRES_PORT=
-POSTGRES_DB=
-POSTGRES_USER=
-POSTGRES_PASSWORD=
+export POSTGRES_HOST=
+export POSTGRES_PORT=
+export POSTGRES_DB=
+export POSTGRES_USER=
+export POSTGRES_PASSWORD=
 ```
 
 The `datagen` program will read the environment variables from `.env` in the current working directory.
+If you are running `datagen` from a different directory, you can first `source /path/to/your/.env` before running the command.
 
 
 ## Usage

src/formats/avroFormat.ts

@@ -10,7 +10,7 @@ export class AvroFormat implements OutputFormat {
     private registry: SchemaRegistry;
 
     static async create(): Promise<AvroFormat> {
-        const url = Env.required("SCHEMA_REGISTRY_URL");
+        const url = Env.optional("SCHEMA_REGISTRY_URL", "http://localhost:8081");
         const username = Env.optional("SCHEMA_REGISTRY_USERNAME", null);
         const password = Env.optional("SCHEMA_REGISTRY_PASSWORD", null);
 

src/kafka/cleanKafka.ts

@@ -4,7 +4,7 @@ import alert from 'cli-alerts';
 import { Env } from '../utils/env.js';
 
 async function deleteSchemaSubjects(topics: any): Promise<void> {
-    const schemaRegistryUrl = Env.required("SCHEMA_REGISTRY_URL");
+    const schemaRegistryUrl = Env.optional("SCHEMA_REGISTRY_URL", "http://localhost:8081");
 
     for await (const topic of topics) {
         const url = `${schemaRegistryUrl}/subjects/${topic}-value?permanent=false`;

src/utils/env.ts

@@ -1,4 +1,5 @@
 import dotenv from 'dotenv';
+import alert from 'cli-alerts';
 
 export class Env {
 
@@ -11,7 +12,10 @@ export class Env {
         if (!value) {
             alert({
                 type: `error`,
-                name: `Missing required environment variable ${name}`
+                name:
+                    `Missing required environment variable ${name}\n
+                    Provide environment variable inline or export it to your environment.
+                    `
             });
             process.exit(1);
         }
@@ -20,6 +24,20 @@ export class Env {
     }
 
     static optional(name: string, orElse: string): string {
-        return process.env[name] ?? orElse;
+        const value = process.env[name];
+        if (!value && global.debug) {
+            alert({
+                type: `warning`,
+                name: `Environment variables`,
+                msg:
+                    `\nEnvironment variable ${name} not found.
+                    Using default alternative.
+                    If you meant to include this environment variable, export it or
+                    run this command from a directory with a .env file that includes it.
+                    See https://github.com/MaterializeInc/datagen/ for more detail.
+                    `
+            })
+        }
+        return value ?? orElse;
     }
 }