API versioning with routing in Nginx - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to route requests to version 1 of the API.

Nginx

location /api/v1/ {
    proxy_pass http://backend[1];
}

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

A/v1

B/v1/

C/v2/

D/

Attempts:

3 left

💡 Hint

Common Mistakes

Omitting the trailing slash in proxy_pass causes incorrect URL forwarding.

Using the wrong version path in proxy_pass.

The proxy_pass directive must include the trailing slash to correctly forward the URI after /api/v1/.

2fill in blank

medium

Complete the code to route requests to version 2 of the API.

Nginx

location /api/v2/ {
    proxy_pass http://backend[1];
}

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

A/v1/

B/v3/

C/v2/

D/

Attempts:

3 left

💡 Hint

Common Mistakes

Using the wrong version number in proxy_pass.

Missing the trailing slash in proxy_pass.

Requests to /api/v2/ should be proxied to the backend's /v2/ path with a trailing slash.

3fill in blank

hard

Fix the error in the location block to correctly route to version 1 API.

Nginx

location /api/v1 {
    proxy_pass http://backend[1];
}

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

A/v2/

B/v1

C/

D/v1/

Attempts:

3 left

💡 Hint

Common Mistakes

Missing trailing slash in location causes partial matching issues.

proxy_pass without trailing slash changes the forwarded URI.

The location block must end with a slash to match the path correctly, and proxy_pass must include the trailing slash.

4fill in blank

hard

Fill both blanks to route requests to version 3 API and set a custom header.

Nginx

location /api/v3/ {
    proxy_pass http://backend[1];
    proxy_set_header X-API-Version [2];
}

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

A/v3/

B"v3"

C"v2"

D/v2/

Attempts:

3 left

💡 Hint

Common Mistakes

Using wrong version path in proxy_pass.

Setting header without quotes causing syntax errors.

The proxy_pass must point to /v3/ to route correctly, and the header should reflect the API version "v3".

5fill in blank

hard

Fill all three blanks to create a map for API version routing and use it in proxy_pass.

Nginx

map $uri $backend_path {
    ~^/api/v1/ /v1/;
    ~^/api/v2/ /v2/;
    default [1];
}

location /api/ {
    proxy_pass http://backend[2];
    proxy_set_header X-API-Version [3];
}

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

A/v3/

B$backend_path

C"dynamic"

D/default/

Attempts:

3 left

💡 Hint

Common Mistakes

Not using the map variable in proxy_pass.

Incorrect default path causing routing errors.

Missing quotes around header value.

The default path in the map is /v3/ for other versions, proxy_pass uses the mapped variable $backend_path, and the header is set to "dynamic" to indicate dynamic routing.

Practice

1. What is the main purpose of using API versioning with routing in nginx?

easy

A. To block all API requests except the latest version

B. To combine all API versions into a single endpoint

C. To run multiple API versions side by side and route requests accordingly

D. To disable routing and serve static files only

Solution

1. Step 1: Understand API versioning concept

   API versioning allows different versions of an API to coexist, so clients using older versions still work.

2. Step 2: Role of nginx routing

   nginx uses location blocks to route requests to the correct API version based on the URL path.

3. Final Answer:

   To run multiple API versions side by side and route requests accordingly -> Option C

4. Quick Check:

   API versioning = multiple versions side by side [OK]

Hint: API versioning means routing requests to different versions [OK]

Common Mistakes:

• Thinking API versioning disables old versions
• Assuming all versions merge into one endpoint
• Confusing routing with blocking requests

2. Which nginx configuration snippet correctly routes requests to API version v1 at path /api/v1/?

easy

A. location /api/v1/ { proxy_pass http://backend_v1; }

B. location /api/v1 { proxy_pass http://backend_v1; }

C. location /api/v1/* { proxy_pass http://backend_v1; }

D. location /api/v1$ { proxy_pass http://backend_v1; }

Solution

1. Step 1: Understand nginx location matching

   Using location /api/v1/ matches all requests starting with /api/v1/, including subpaths.

2. Step 2: Check syntax correctness

   location /api/v1/ { proxy_pass http://backend_v1; } uses correct syntax without wildcards or regex, which nginx does not support in this form.

3. Final Answer:

   location /api/v1/ { proxy_pass http://backend_v1; } -> Option A

4. Quick Check:

   Trailing slash in location matches subpaths [OK]

Hint: Use trailing slash in location to match all subpaths [OK]

Common Mistakes:

• Using wildcards (*) in location which nginx does not support
• Missing trailing slash causing partial matches
• Using regex syntax without ~

3. Given this nginx config snippet, what backend will handle a request to /api/v2/users?

location /api/v1/ {
  proxy_pass http://backend_v1;
}
location /api/v2/ {
  proxy_pass http://backend_v2;
}

medium

A. http://backend_v2

B. No backend, 404 error

C. http://backend_v1

D. Both backends in round-robin

Solution

1. Step 1: Match request path to location blocks

   The request path /api/v2/users starts with /api/v2/, so it matches the second location block.

2. Step 2: Determine proxy backend

   The matching location proxies to http://backend_v2, so this backend handles the request.

3. Final Answer:

   http://backend_v2 -> Option A

4. Quick Check:

   Request path prefix matches location prefix [OK]

Hint: Match URL prefix to location prefix to find backend [OK]

Common Mistakes:

• Choosing backend_v1 for /api/v2/ path
• Assuming nginx load balances both backends automatically
• Thinking unmatched paths cause proxy to backend_v1

4. Identify the error in this nginx config for API versioning:

location /api/v1 {
  proxy_pass http://backend_v1;
}
location /api/v2/ {
  proxy_pass http://backend_v2;
}

medium

A. proxy_pass must use IP address, not hostname

B. proxy_pass URLs must include trailing slash

C. location blocks cannot be adjacent

D. Missing trailing slash in first location causes incorrect routing

Solution

1. Step 1: Check location path consistency

   The first location uses /api/v1 without trailing slash, which matches only exact path or prefix differently than /api/v1/.

2. Step 2: Understand routing impact

   Requests like /api/v1/users won't match the first location correctly, causing routing errors.

3. Final Answer:

   Missing trailing slash in first location causes incorrect routing -> Option D

4. Quick Check:

   Trailing slash in location matters for prefix matching [OK]

Hint: Always use trailing slash in location for API version prefixes [OK]

Common Mistakes:

• Ignoring trailing slash difference in location paths
• Thinking proxy_pass URL must have trailing slash
• Believing location blocks cannot be next to each other

5. You want to support API versions v1 and v2 in nginx, but also redirect any request to /api/ without version to v2 by default. Which config snippet achieves this correctly?

hard

A. location /api/ { proxy_pass http://backend_v2; }
location /api/v1/ { proxy_pass http://backend_v1; }

B. location /api/v1/ { proxy_pass http://backend_v1; }
location /api/v2/ { proxy_pass http://backend_v2; }
location /api/ { return 301 /api/v2/; }

C. location /api/ { proxy_pass http://backend_v1; }
location /api/v2/ { proxy_pass http://backend_v2; }

D. location /api/v1/ { proxy_pass http://backend_v1; }
location /api/v2/ { proxy_pass http://backend_v2; }
location /api/ { proxy_pass http://backend_v2; }

Solution

1. Step 1: Define explicit version locations

   Locations for /api/v1/ and /api/v2/ proxy requests to respective backends.

2. Step 2: Redirect base /api/ to default version

   Using return 301 /api/v2/; in /api/ location sends clients to v2 URL, ensuring default version usage.

3. Final Answer:

   location /api/v1/ { proxy_pass http://backend_v1; } location /api/v2/ { proxy_pass http://backend_v2; } location /api/ { return 301 /api/v2/; } -> Option B

4. Quick Check:

   Redirect base path to default version with return 301 [OK]

Hint: Use return 301 to redirect base API path to default version [OK]

Common Mistakes:

• Proxying /api/ directly instead of redirecting
• Overlapping location blocks causing conflicts
• Using proxy_pass in /api/ without redirect