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Danger: smarter, faster and more
efficient code reviews
Camila Maia
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Who am I? ● Backend Engineer in the Mobile
Squad
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Code Reviews
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Code Reviews:
They take
time!
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How can we make code reviews
smarter, faster and more efficient?
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Automation
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● An automated reviewer
of your code
● Ruby gem
● Runs after your CI
automating your
team's conventions
surrounding code
review
What?
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CI Systems
Peer Review Tools
Source Control
Management (SCM)
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It is as generic as you want
Like Unit Tests, but for your Team
Culture.
Formalize your Pull Request
etiquette.
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Why?
● More precision on PRs
● Take less time on code reviews
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With Danger, you can leave humans
to think about harder problems.
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How does it work?
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Domain Specific Languages (DSL’s)
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# Make it more obvious that a PR is a work in progress and shouldn't be
merged yet
if github.pr_title.downcase.include? "[wip]"
warn("PR is classed as Work in Progress")
end
# Warn when there is a big PR
warn("Big PR") if git.lines_of_code > 500
# Warn if there's no description
warn("Please, provide a description to your PR") if github.pr_body.empty?
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IMPORT FROM A LOCAL FILE REFERENCE
danger.import_plugin("danger/plugins/watch_plugin.rb")
RETURNS THE NAME OF THE CURRENT SCM PROVIDER BEING USED.
danger.scm_provider
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Plugins
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How to integrate it?
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1
INCLUDE DANGER
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CREATE DANGERFILE
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CREATE AN ACCOUNT
FOR DANGER
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CREATE AN ACCESS
TOKEN FOR DANGER
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SETTING UP DANGER TO
RUN ON YOUR CI
Setup
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Include Danger
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Create a Dangerfile
DON'T ALLOW A FILE TO BE DELETED
deleted = git.deleted_files.include? "my/favourite.file"
fail "Don't delete my precious" if deleted
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Create an Account and an Access Token for Danger
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Setting up Danger to Run on your Ci
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Our Experience
● Gradual integration works
better
● The culture is the most
important part
● It takes time to coworkers get
engaged
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Our Experience
● Pair programming
● Check other projects
● It is awesome for open source
projects
● Inheritance might be not that
easy
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Community
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What is next?
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What?
● Hosted Danger
● Typescript
● Danger JS
● It is a really recent project
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Why?
● More flexibility:
○ Scheduler, for example
● Settings are more powerful
○ Composition besides inheritance
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Why?
● Easier to test
● Installation can literally be a
single click on the website
● It is a GitHub App (not an
account)
○ no need to consider scope
for tokens
○ no need to ensure bot has
access to repo
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Stop saying "you forgot to …" in
code review
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THANK YOU
FOR YOUR TIME
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@_camila_maia_ camilamaia
https://loadsmart.com/careers/
WE ARE HIRING!