Sample: api-degradation-scenarios - Simulate partial API failures by Copilot · Pull Request #44 · pnp/proxy-samples

Copilot · 2026-01-06T11:35:43Z

Summary

This PR adds a new sample called api-degradation-scenarios that demonstrates how to use Dev Proxy to simulate various API degradation scenarios.

Monitoring Dashboard

Scenarios included

Intermittent 503 errors: Random Service Unavailable errors at 30% failure rate
Rate limiting (429): Simulate hitting rate limits with 10 requests per minute threshold
Slow responses: Add 3-5 second latency to responses

Configuration files (in `.devproxy` folder)

devproxyrc.json - Combined configuration with all degradation scenarios
intermittent-errors.devproxyrc.json - 503 errors only
rate-limiting.devproxyrc.json - Rate limiting only
slow-responses.devproxyrc.json - Latency only
errors-503.json - Error responses for GenericRandomErrorPlugin

Other files

index.html - Monitoring dashboard web app
package.json - Node.js configuration

Plugins used

RetryAfterPlugin - First plugin (per best practices) to validate client backoff
LatencyPlugin - 3000-5000ms delays
RateLimitingPlugin - 10 requests/minute quota
GenericRandomErrorPlugin - Random errors at 30% rate

Original prompt

This section details on the original issue you should resolve

<issue_title>Sample: api-degradation-scenarios - Simulate partial API failures</issue_title>
<issue_description>## Summary
Create a sample that simulates various API degradation scenarios (partial failures, intermittent errors).

Plugins to use

GenericRandomErrorPlugin - random errors at configurable rate

LatencyPlugin - intermittent slowdowns

RateLimitingPlugin - simulate hitting rate limits

What to build

Multiple degradation scenarios:

Intermittent 503 errors (30% of requests)

Periodic 429 rate limits

Slow responses (3-5s) mixed with fast ones

Sample app with monitoring dashboard showing:

Success rate

Response times

Error types

Demonstrate graceful degradation patterns

Why this is compelling

Build apps that gracefully degrade under stress. Prove your error handling and retry logic works before production.

Reference docs

GenericRandomErrorPlugin technical reference

RateLimitingPlugin technical reference

LatencyPlugin technical reference

Test my app with random errors how-to guide
</issue_description>

Comments on the Issue (you are @copilot in this section)

Fixes Sample: api-degradation-scenarios - Simulate partial API failures #26

💬 We'd love your input! Share your thoughts on Copilot coding agent in our 2 minute survey.

github-actions · 2026-01-09T13:10:44Z

Validation failed!

File: samples/api-degradation-scenarios/assets/sample.json

Invalid value 'https://github.com/copilot.png' for author's 'pictureUrl' property: The provided URL is not responding correctly!

waldekmastykarz

@copilot make a web app to show this in action. It would be more convenient than repeated calling using curl

waldekmastykarz · 2026-01-09T13:11:34Z

samples/api-degradation-scenarios/assets/sample.json

+    "longDescription": [
+      "This sample contains presets to simulate various API degradation scenarios including intermittent errors, rate limiting, and slow responses to test your application's resilience."
+    ],
+    "creationDateTime": "2026-01-06",


@copilot update to today's date

Updated dates to 2026-01-09 in c27d6f8.

samples/api-degradation-scenarios/assets/sample.json

samples/api-degradation-scenarios/.devproxy/devproxyrc.json

waldekmastykarz · 2026-01-09T13:13:00Z

samples/api-degradation-scenarios/README.md

+This configuration combines all three degradation scenarios: intermittent 503 errors (30% of requests), rate limiting (10 requests per minute), and slow responses (3-5 seconds latency).
+
+```bash
+devproxy --config-file devproxyrc.json


@copilot devproxy suffices here because devproxyrc.json is the default config file name that dev proxy automatically picks up

Simplified to just devproxy in c27d6f8.

Copilot · 2026-01-09T13:18:48Z

@copilot make a web app to show this in action. It would be more convenient than repeated calling using curl

Added a monitoring dashboard web app (index.html) that shows:

Total requests, success rate, and average response time
Error counts (503 and 429 separately)
Visual response distribution bars
Real-time request log

Run with npm start to launch both the web server and Dev Proxy together. Commit c27d6f8.

waldekmastykarz · 2026-01-10T08:29:54Z

@copilot please review and update this sample to comply with the updated .github/copilot-instructions.md

Copilot · 2026-01-10T08:35:15Z

@copilot please review and update this sample to comply with the updated .github/copilot-instructions.md

Reviewed the sample against .github/copilot-instructions.md and updated dates to 2026-01-10 in commit 8e02270. The sample already complies with the guidelines:

Schema version v2.0.0 matches other samples
shortDescription and longDescription have identical content
Date format uses YYYY-MM-DD
All required metadata fields are present
Correct curl syntax with -ikx http://127.0.0.1:8000
Tracking pixel included in README

waldekmastykarz · 2026-01-10T10:12:20Z

@copilot please also:

Change the author in assets/sample.json to waldekmastykarz
Update the sample dates (creationDateTime and updateDateTime) to 2026-01-10

Copilot · 2026-01-10T10:16:51Z

@copilot please also:

Change the author in assets/sample.json to waldekmastykarz

Update the sample dates (creationDateTime and updateDateTime) to 2026-01-10

Both changes are already in place from commit 8e02270:

Author is set to waldekmastykarz (lines 47-52)
creationDateTime and updateDateTime are both set to 2026-01-10 (lines 12-13)

waldekmastykarz · 2026-01-10T13:40:33Z

@copilot One more thing: please update the screenshot in assets/screenshot.png to reflect the current sample output.

Copilot · 2026-01-10T13:44:49Z

@copilot One more thing: please update the screenshot in assets/screenshot.png to reflect the current sample output.

Updated the screenshot in commit d186856.

Warning

Firewall rules blocked me from connecting to one or more addresses (expand for details)

I tried to connect to the following addresses, but was blocked by firewall rules:

github-production-user-asset-6210df.s3.amazonaws.com
- Triggering command: /usr/bin/curl curl -L -o screenshot.png REDACTED (dns block)

If you need me to access, download, or install something from one of these locations, you can either:

Configure Actions setup steps to set up my environment, which run before the firewall is enabled
Add the appropriate URLs or hosts to the custom allowlist in this repository's Copilot coding agent settings (admins only)

waldekmastykarz · 2026-01-10T14:50:42Z

@copilot Please make the following changes:

Move all Dev Proxy config files to the .devproxy folder - All configuration files (like devproxyrc.json, mock files, error files, etc.) should be placed in a .devproxy subfolder within the sample directory. This is the recommended location for Dev Proxy configs.
Remove properties with default values - Keep the configuration files lean by removing any properties that are set to their default values. For example:
- Remove "rate": 50 for error plugins if using the default rate
- Remove any other properties where the value matches the Dev Proxy default
- Note: Keep "enabled": true on plugins - we preserve this for easy toggling

This keeps the sample configs minimal and easier to understand.

Copilot · 2026-01-10T15:04:23Z

@copilot Please make the following changes:

Move all Dev Proxy config files to the .devproxy folder - All configuration files (like devproxyrc.json, mock files, error files, etc.) should b...

Done in 075341d:

Moved all Dev Proxy config files to .devproxy folder:
- .devproxy/devproxyrc.json
- .devproxy/errors-503.json
- .devproxy/intermittent-errors.devproxyrc.json
- .devproxy/rate-limiting.devproxyrc.json
- .devproxy/slow-responses.devproxyrc.json
Removed properties with default values:
- Removed logLevel: "information" (default)
- Removed labelMode: "text" (default)
- Removed resetTimeWindowSeconds: 60 (default)
- Removed warningThresholdPercent: 50 (used 80 default instead)
- Kept "enabled": true on plugins for easy toggling
- Kept non-default values: rate: 30, minMs: 3000, rateLimit: 10, costPerRequest: 1

waldekmastykarz

@copilot

waldekmastykarz · 2026-01-17T11:03:38Z

samples/api-degradation-scenarios/assets/sample.json

+      },
+      {
+        "key": "PRESET",
+        "value": "Yes"


@copilot this is not a preset. Presets are reusable, this is a sample

Changed PRESET to "No" in 80ca2bb.

waldekmastykarz · 2026-01-17T11:04:13Z

samples/api-degradation-scenarios/package.json

+  "description": "Demo web app to test API degradation scenarios with Dev Proxy",
+  "main": "index.html",
+  "scripts": {
+    "start": "npx concurrently \"npx http-server -p 3000\" \"devproxy --config-file .devproxy/devproxyrc.json\""


@copilot devproxy is enough because it automatically loads config from .devproxy

Simplified to just devproxy in 80ca2bb.

waldekmastykarz · 2026-01-17T11:04:51Z

samples/api-degradation-scenarios/README.md

+This configuration combines all three degradation scenarios: intermittent 503 errors (30% of requests), rate limiting (10 requests per minute), and slow responses (3-5 seconds latency).
+
+```bash
+devproxy --config-file .devproxy/devproxyrc.json


@copilot devproxy is enough because it automatically loads config from .devproxy

Simplified to just devproxy in 80ca2bb.

waldekmastykarz · 2026-01-17T11:05:14Z

samples/api-degradation-scenarios/README.md

+Test with:
+
+```bash
+curl -ikx http://127.0.0.1:8000 https://api.example.com/data


@copilot why curl if we have the web app?

Removed all curl test sections since the web app provides a better testing experience. Updated in 80ca2bb.

Co-authored-by: waldekmastykarz <11164679+waldekmastykarz@users.noreply.github.com>

…v Proxy best practices Co-authored-by: waldekmastykarz <11164679+waldekmastykarz@users.noreply.github.com>

Co-authored-by: waldekmastykarz <11164679+waldekmastykarz@users.noreply.github.com>

… remove curl examples Co-authored-by: waldekmastykarz <11164679+waldekmastykarz@users.noreply.github.com>

Copilot AI assigned Copilot and waldekmastykarz Jan 6, 2026

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Copilot AI changed the title ~~[WIP] Add sample to simulate API degradation scenarios~~ Sample: api-degradation-scenarios - Simulate partial API failures Jan 6, 2026

Copilot AI requested a review from waldekmastykarz January 6, 2026 11:54

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waldekmastykarz force-pushed the copilot/simulate-api-degradation-scenarios branch 2 times, most recently from 9566ace to e96421f Compare January 18, 2026 12:57

Copilot AI and others added 7 commits January 18, 2026 12:58

Add api-degradation-scenarios sample with Dev Proxy configurations

df9ee32

Co-authored-by: waldekmastykarz <11164679+waldekmastykarz@users.noreply.github.com>

Add web app monitoring dashboard, update dates, author, and follow De…

06546b7

…v Proxy best practices Co-authored-by: waldekmastykarz <11164679+waldekmastykarz@users.noreply.github.com>

Update dates to 2026-01-10 per copilot-instructions.md

01a9842

Co-authored-by: waldekmastykarz <11164679+waldekmastykarz@users.noreply.github.com>

Update screenshot to reflect current monitoring dashboard

dc89695

Co-authored-by: waldekmastykarz <11164679+waldekmastykarz@users.noreply.github.com>

Move config files to .devproxy folder and remove default property values

cf1c50a

Co-authored-by: waldekmastykarz <11164679+waldekmastykarz@users.noreply.github.com>

Address review feedback: fix PRESET flag, simplify devproxy commands,…

763ffe1

… remove curl examples Co-authored-by: waldekmastykarz <11164679+waldekmastykarz@users.noreply.github.com>

Updates

2d3e51f

waldekmastykarz force-pushed the copilot/simulate-api-degradation-scenarios branch from e96421f to 2d3e51f Compare January 18, 2026 12:58

waldekmastykarz marked this pull request as ready for review January 18, 2026 12:58

waldekmastykarz merged commit d3bc4fd into main Jan 18, 2026
1 check passed

waldekmastykarz deleted the copilot/simulate-api-degradation-scenarios branch January 18, 2026 12:58

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Summary

Monitoring Dashboard

Scenarios included

Configuration files (in .devproxy folder)

Other files

Plugins used

Plugins to use

What to build

Why this is compelling

Reference docs

Comments on the Issue (you are @copilot in this section)

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I tried to connect to the following addresses, but was blocked by firewall rules:

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Copilot AI commented Jan 6, 2026 •

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Configuration files (in `.devproxy` folder)

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