Environment configuration in Microservices - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to load environment variables in a microservice.

Microservices

const config = process.env.[1];

Drag options to blanks, or click blank then click option'

ANODE_ENV

BCONFIG_PATH

CPORT

DSERVICE_NAME

Attempts:

3 left

💡 Hint

Common Mistakes

Using a variable that defines port or service name instead of environment.

The NODE_ENV variable is commonly used to determine the environment (development, production, etc.) in microservices.

2fill in blank

medium

Complete the code to read a configuration file path from environment variables.

Microservices

const configPath = process.env.[1] || './config/default.json';

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ACONFIG_FILE

BCONFIG_PATH

CCONFIG_DIR

DCONFIG_LOCATION

Attempts:

3 left

💡 Hint

Common Mistakes

Using variable names that do not clearly indicate a file path.

CONFIG_PATH is a common environment variable name used to specify the path to a configuration file.

3fill in blank

hard

Fix the error in the code to correctly parse environment variables for service port.

Microservices

const port = parseInt(process.env.[1], 10) || 3000;

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APORT

BAPP_PORT

CSERVICE_PORT

DPORT_NUMBER

Attempts:

3 left

💡 Hint

Common Mistakes

Using non-standard or custom variable names that may not be recognized by hosting platforms.

PORT is the standard environment variable name for service port in microservices.

4fill in blank

hard

Fill both blanks to create a dictionary comprehension that filters environment variables starting with 'APP_'.

Microservices

const appEnvVars = Object.fromEntries(Object.entries(process.env).filter(([key, value]) => key.[1]('APP_') === [2]));

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AstartsWith

BindexOf

C0

D-1

Attempts:

3 left

💡 Hint

Common Mistakes

Using indexOf without comparing to 0, or using -1 incorrectly.

Use indexOf('APP_') === 0 which returns true if the key starts with 'APP_'. indexOf returns 0 if the substring starts at the beginning of the string. Alternatively, startsWith('APP_') returns a boolean directly.

5fill in blank

hard

Fill all three blanks to create a function that loads environment variables with defaults.

Microservices

function getEnvVar(name, defaultValue) {
  return process.env[[1]] ?? [2] ?? [3];
}

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Aname

BdefaultValue

C''

Dnull

Attempts:

3 left

💡 Hint

Common Mistakes

Using null as the last fallback instead of an empty string, which may cause issues when expecting strings.

The function returns the environment variable by name. If undefined, it returns defaultValue. If that is also undefined or null, it returns an empty string '' as a fallback.

Practice

1. What is the main purpose of environment configuration in microservices?

easy

A. To write all configuration directly inside the code

B. To hardcode database credentials in the source files

C. To separate settings from code for easier management

D. To avoid using any configuration for faster deployment

Solution

1. Step 1: Understand environment configuration role

   Environment configuration means keeping settings like URLs, credentials, and flags outside the code.

2. Step 2: Identify benefits of separating settings

   This separation allows the same code to run in different environments (dev, test, prod) safely and easily.

3. Final Answer:

   To separate settings from code for easier management -> Option C

4. Quick Check:

   Settings separate from code = B [OK]

Hint: Settings outside code means environment configuration [OK]

Common Mistakes:

• Confusing configuration with code logic
• Hardcoding sensitive data inside source files
• Ignoring environment differences

2. Which of the following is the correct way to access an environment variable named DB_HOST in a microservice?

easy

A. getEnv('DB_HOST')

B. config.get('DB_HOST')

C. env.DB_HOST()

D. process.env.DB_HOST

Solution

1. Step 1: Identify common environment variable access syntax

   In many microservice platforms, environment variables are accessed via process.env.VARIABLE_NAME.

2. Step 2: Match the correct syntax for DB_HOST

   The correct way is process.env.DB_HOST, which reads the variable from the environment.

3. Final Answer:

   process.env.DB_HOST -> Option D

4. Quick Check:

   Environment variables use process.env = A [OK]

Hint: Use process.env.VAR to read environment variables [OK]

Common Mistakes:

• Using function calls instead of direct access
• Confusing config libraries with environment variables
• Using incorrect object names like env or getEnv

3. Given this code snippet in a microservice:

const port = process.env.PORT || 3000;
console.log(port);

If the environment variable PORT is set to 8080, what will be printed?

medium

A. 8080

B. undefined

C. null

D. 3000

Solution

1. Step 1: Understand the fallback logic

   The code uses process.env.PORT || 3000, meaning if PORT is set, use it; otherwise, use 3000.

2. Step 2: Apply the given environment variable value

   Since PORT is set to 8080, the variable port will be 8080.

3. Final Answer:

   8080 -> Option A

4. Quick Check:

   PORT set to 8080 means output 8080 [OK]

Hint: If env var exists, use it; else fallback value [OK]

Common Mistakes:

• Assuming fallback value always prints
• Confusing undefined with fallback
• Ignoring environment variable presence

4. A microservice fails to read environment variables after deployment. Which is the most likely cause?

medium

A. Environment variables were not set in the deployment environment

B. The code uses process.env to read variables

C. The microservice has no network connection

D. The source code has syntax errors unrelated to config

Solution

1. Step 1: Identify common reasons for missing environment variables

   If the microservice cannot read environment variables, often they were not set or loaded properly in the deployment environment.

2. Step 2: Eliminate other options

   Using process.env is correct syntax; network issues or unrelated syntax errors won't cause missing env vars.

3. Final Answer:

   Environment variables were not set in the deployment environment -> Option A

4. Quick Check:

   Missing env vars usually mean not set in environment [OK]

Hint: Check if env vars are set in deployment environment [OK]

Common Mistakes:

• Blaming code syntax for missing env vars
• Ignoring deployment environment setup
• Assuming network issues cause env var problems

5. You want to deploy the same microservice code to development, staging, and production environments. Which approach best uses environment configuration to handle different database URLs safely?

hard

A. Hardcode all database URLs in the source code and comment/uncomment as needed

B. Use environment variables to set the database URL for each environment separately

C. Store all database URLs in a single config file checked into source control

D. Use a random database URL generated at runtime

Solution

1. Step 1: Understand the need for environment-specific settings

   Each environment (dev, staging, prod) has different database URLs for safety and isolation.

2. Step 2: Choose a method that separates config from code and supports environment differences

   Using environment variables allows setting different URLs without changing code or risking secrets in source control.

3. Step 3: Evaluate other options

   Hardcoding or single config files risk errors and security issues; random URLs are impractical.

4. Final Answer:

   Use environment variables to set the database URL for each environment separately -> Option B

5. Quick Check:

   Env vars per environment = safe config management [OK]

Hint: Use env vars for environment-specific secrets and URLs [OK]

Common Mistakes:

• Hardcoding secrets in code
• Checking sensitive config into source control
• Using random or unsafe config values