CI/CD pipeline setup in Deno - Cheat Sheet & Quick Revision

Recall & Review

beginner

What does CI/CD stand for in software development?

CI/CD stands for Continuous Integration and Continuous Delivery (or Continuous Deployment). It is a practice to frequently merge code changes and automatically deliver them to production or testing environments.

beginner

Why is a CI/CD pipeline important for a Deno project?

A CI/CD pipeline automates testing, building, and deploying your Deno project. This helps catch errors early, speeds up delivery, and ensures consistent quality without manual steps.

beginner

Which command runs tests in a Deno project?

The command is deno test. It runs all test files in the project to check if the code works as expected.

beginner

What is a simple example of a CI step for a Deno project?

A simple CI step runs deno test to check code correctness every time new code is pushed to the repository.

beginner

Name one popular tool to create CI/CD pipelines that can work with Deno projects.

GitHub Actions is a popular tool that can automate CI/CD pipelines for Deno projects by running workflows on code changes.

What is the first step in a typical CI/CD pipeline for a Deno project?

A Merge code to main branch

B Run tests using <code>deno test</code>

C Deploy to production

D Write documentation

The first step is usually to run tests to ensure the code works before deploying or merging.

Which file is commonly used to define GitHub Actions workflows for CI/CD?

A deno.json

B package.json

C .github/workflows/*.yml

D Dockerfile

GitHub Actions workflows are defined in YAML files inside the .github/workflows directory.

What command installs dependencies in a Deno project?

A deno cache

B deno install

C npm install

D deno get

deno cache downloads and caches remote dependencies for faster runs.

In CI/CD, what does 'Continuous Delivery' mean?

A Running tests continuously

B Automatically deploying code to production after tests pass

C Writing code continuously

D Manually deploying code after tests pass

Continuous Delivery means code is automatically prepared for deployment and can be deployed manually after passing tests.

Which of these is NOT a benefit of using CI/CD pipelines?

A Manual error-prone deployments

B Reduced integration problems

C Consistent build and test process

D Faster feedback on code changes

Manual error-prone deployments are what CI/CD pipelines help to avoid, not a benefit.

Describe the main steps you would include in a CI/CD pipeline for a Deno project.

Think about testing, preparing code, and delivering it automatically.

Explain why automating testing and deployment is helpful when working on software projects.

Consider how automation helps teams work better and faster.

Practice

1. What is the main purpose of setting up a CI/CD pipeline for a Deno project?

easy

A. To automate testing and deployment processes

B. To write code faster manually

C. To increase the size of the project files

D. To disable automatic updates

Solution

1. Step 1: Understand CI/CD pipeline purpose

   A CI/CD pipeline automates repetitive tasks like testing and deployment to save time and reduce errors.

2. Step 2: Match purpose to options

   Only To automate testing and deployment processes describes automation of testing and deployment, which is the main goal.

3. Final Answer:

   To automate testing and deployment processes -> Option A

4. Quick Check:

   CI/CD automates testing and deployment = A [OK]

Hint: CI/CD means automating build, test, and deploy steps [OK]

Common Mistakes:

• Thinking CI/CD is about writing code manually
• Confusing CI/CD with increasing file size
• Believing CI/CD disables updates

2. Which of the following is the correct command to run tests in a Deno CI/CD pipeline?

easy

A. deno test

B. deno run test

C. deno build test

D. deno deploy test

Solution

1. Step 1: Recall Deno test command

   The official command to run tests in Deno is deno test.

2. Step 2: Compare options with correct syntax

   Only deno test matches the correct command syntax for running tests.

3. Final Answer:

   deno test -> Option A

4. Quick Check:

   Run tests with 'deno test' = A [OK]

Hint: Use 'deno test' to run tests, not 'deno run test' [OK]

Common Mistakes:

• Using 'deno run test' which runs a script, not tests
• Confusing build or deploy commands with test command
• Adding extra words like 'build' or 'deploy' incorrectly

3. Given this CI step in a Deno pipeline:

steps:
  - name: Run tests
    run: deno test --unstable
  - name: Bundle code
    run: deno bundle mod.ts bundle.js

What will be the result if tests fail?

medium

A. The pipeline skips tests and bundles code

B. The pipeline stops and does not bundle the code

C. The pipeline continues and bundles the code anyway

D. The pipeline deletes the bundle.js file

Solution

1. Step 1: Understand default pipeline behavior on failure

   In most CI/CD systems, if a test step fails, the pipeline stops to prevent deploying broken code.

2. Step 2: Apply to given steps

   If deno test --unstable fails, the next step to bundle code will not run.

3. Final Answer:

   The pipeline stops and does not bundle the code -> Option B

4. Quick Check:

   Failed tests stop pipeline = C [OK]

Hint: Failed tests usually stop pipeline to avoid bad deploys [OK]

Common Mistakes:

• Assuming pipeline continues after test failure
• Thinking tests are skipped automatically
• Believing files get deleted on test failure

4. You wrote this pipeline step:

steps:
  - name: Bundle code
    run: deno bundle mod.ts -o bundle.js

But the pipeline fails with an error. What is the likely cause?

medium

A. The pipeline requires 'deno test' before bundling

B. The file 'mod.ts' does not exist

C. The 'run' keyword is misspelled

D. The '-o' flag is not valid for 'deno bundle'

Solution

1. Step 1: Check 'deno bundle' syntax

   The correct syntax to specify output file is: deno bundle input.ts output.js without '-o' flag.

2. Step 2: Identify error cause

   Using '-o' causes an error because 'deno bundle' does not support it.

3. Final Answer:

   The '-o' flag is not valid for 'deno bundle' -> Option D

4. Quick Check:

   Output file is positional, no '-o' flag = D [OK]

Hint: Use positional output filename, not '-o', with deno bundle [OK]

Common Mistakes:

• Adding '-o' flag like other bundlers
• Assuming file existence without checking
• Thinking 'run' keyword is wrong
• Believing tests must run before bundling always

5. You want to create a CI/CD pipeline that runs tests, bundles code, and then deploys only if tests pass. Which YAML snippet correctly represents this sequence?

hard

A. steps:
- run: deno bundle mod.ts bundle.js
- run: deno test
- run: deploy.sh

B. steps:
- run: deploy.sh
- run: deno test
- run: deno bundle mod.ts bundle.js

C. steps:
- run: deno test
- run: deno bundle mod.ts bundle.js
- run: deploy.sh

D. steps:
- run: deno test
- run: deploy.sh
- run: deno bundle mod.ts bundle.js

Solution

1. Step 1: Determine correct order for CI/CD steps

   Tests must run first to verify code, then bundle code, then deploy if tests pass.

2. Step 2: Match order with options

   Only steps: - run: deno test - run: deno bundle mod.ts bundle.js - run: deploy.sh runs tests first, then bundles, then deploys.

3. Final Answer:

   Tests first, then bundle, then deploy -> Option C

4. Quick Check:

   Test -> Bundle -> Deploy = B [OK]

Hint: Test first, then bundle, then deploy in pipeline steps [OK]

Common Mistakes:

• Deploying before tests run
• Bundling before tests
• Changing step order incorrectly