Initial app setup.

Author: cristiangreco

.github/dependabot.yml

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+version: 2
+updates:
+  - package-ecosystem: 'bundler'
+    directory: '/'
+    schedule:
+      interval: 'daily'
+  - package-ecosystem: 'github-actions'
+    directory: '/'
+    schedule:
+      interval: 'daily'

Dockerfile

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+FROM ruby:2.7.2-alpine
+
+COPY Gemfile Gemfile.lock app.rb config.ru /srv/app/
+WORKDIR /srv/app
+RUN bundle install
+
+EXPOSE 9292
+
+CMD ["bundle", "exec", "rackup", "--host", "0.0.0.0"]

Gemfile

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+source "https://rubygems.org"
+
+ruby "2.7.2"
+
+gem "sinatra"
+gem "prometheus-client"

Gemfile.lock

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+GEM
+  remote: https://rubygems.org/
+  specs:
+    mustermann (1.1.1)
+      ruby2_keywords (~> 0.0.1)
+    prometheus-client (2.1.0)
+    rack (2.2.3)
+    rack-protection (2.1.0)
+      rack
+    ruby2_keywords (0.0.4)
+    sinatra (2.1.0)
+      mustermann (~> 1.0)
+      rack (~> 2.2)
+      rack-protection (= 2.1.0)
+      tilt (~> 2.0)
+    tilt (2.0.10)
+
+PLATFORMS
+  ruby
+
+DEPENDENCIES
+  prometheus-client
+  sinatra
+
+RUBY VERSION
+   ruby 2.7.2p137
+
+BUNDLED WITH
+   2.1.4

README.md

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+# Sinatra app
+
+Example Sinatra app with Prometheus instrumentation.
+
+Run with:
+
+```sh
+$ bundle exec rackup
+```
+
+The app will run at `http://localhost:9292`.
+
+You can check the output of the default `/` route with `curl`:
+
+```sh
+$ curl http://localhost:9292
+Hello world!
+```
+
+Prometheus metrics are exposed at `http://localhost:9292/metrics`.

app.rb

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+# frozen_string_literal: true
+
+require "sinatra"
+
+get "/" do
+  "Hello world!"
+end

config.ru

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+# frozen_string_literal: true
+
+require "./app"
+
+require "prometheus/middleware/collector"
+require "prometheus/middleware/exporter"
+
+use Prometheus::Middleware::Collector
+use Prometheus::Middleware::Exporter
+
+run Sinatra::Application