Slack message implementation

These changes add and configure Slack Poster to the application,
so it notifies the owners of the affected gems via their team's Slack channels.

.github/workflows/version_checker.yml

@@ -3,7 +3,10 @@ name: "Gem Version Checker"
 on:
   workflow_dispatch: {}
   schedule:
-    - cron:  '00 10 * * 1-5' # Runs at 10:00, Monday through Friday.
+    - cron:  '00 13 * * 3' # Runs at 13:00, Every Wednesday.
+
+env:
+  SLACK_WEBHOOK: ${{ secrets.SLACK_WEBHOOK }}
 
 jobs:
   gem-version-checker:

Gemfile

@@ -4,6 +4,7 @@ source "https://rubygems.org"
 
 gem "octokit"
 gem "rake"
+gem "slack-poster"
 gem "webmock"
 
 group :development, :test do

Gemfile.lock

@@ -101,6 +101,8 @@ GEM
     sawyer (0.9.2)
       addressable (>= 2.3.5)
       faraday (>= 0.17.3, < 3)
+    slack-poster (2.2.2)
+      faraday (>= 1.0.0)
     tzinfo (2.0.6)
       concurrent-ruby (~> 1.0)
     unicode-display_width (2.5.0)
@@ -117,6 +119,7 @@ DEPENDENCIES
   rake
   rspec
   rubocop-govuk
+  slack-poster
   webmock
 
 BUNDLED WITH

lib/version_checker.rb

@@ -4,29 +4,45 @@
 require "net/http"
 require "json"
 require "octokit"
+require "slack/poster"
 
 class HttpError < RuntimeError
 end
 
 class VersionChecker
   GEMS_API = URI("https://docs.publishing.service.gov.uk/gems.json")
 
+  def slack_options(team)
+    {
+      icon_emoji: ":gem:",
+      username: "Gem Release Bot",
+      channel: team.to_s,
+    }
+  end
+
   def print_version_discrepancies
     all_govuk_gems.group_by { |gem| gem["team"] }.each do |team, gems|
-      message = gems.filter_map { |gem|
-        repo_name = gem["app_name"]
-        rubygems_version = fetch_rubygems_version(repo_name)
-        if !rubygems_version.nil? &&
-            files_changed_since_tag(repo_name, "v#{rubygems_version}").any? { |path| path_built_into_gem?(path) }
-          "  #{repo_name} has unreleased changes since v#{rubygems_version}"
-        end
-      }.join("\n")
+      message = message_builder(gems)
+
+      puts "team: #{team}\n#{message}"
 
-      puts team
-      puts message
+      poster = Slack::Poster.new(ENV["SLACK_WEBHOOK"], slack_options(team))
+      poster.send_message(message.to_s) unless message.nil?
     end
   end
 
+  def message_builder(gems)
+    gems.filter_map { |gem|
+      repo_name = gem["app_name"]
+      repo_url = gem["links"]["repo_url"]
+      rubygems_version = fetch_rubygems_version(repo_name)
+      if !rubygems_version.nil? &&
+          files_changed_since_tag(repo_name, "v#{rubygems_version}").any? { |path| path_built_into_gem?(path) }
+        "  <#{repo_url}|#{repo_name}> has unreleased changes since v#{rubygems_version}"
+      end
+    }.join("\n")
+  end
+
   def all_govuk_gems
     res = Net::HTTP.get_response(GEMS_API)
     if res.is_a?(Net::HTTPSuccess)

spec/version_checker_spec.rb

@@ -6,27 +6,35 @@
 RSpec.describe VersionChecker do
   subject(:version_checker) { described_class.new }
 
+  let(:webhook_url) { "https://slack/webhook" }
+
+  before do
+    ENV["SLACK_WEBHOOK"] = webhook_url
+  end
+
   it "fetches version number of a gem from rubygems" do
     stub_rubygems_call("6.0.1")
 
     expect(version_checker.fetch_rubygems_version("example")).to eq("6.0.1")
   end
 
   it "detects when there are no files changed since the last release that are built into the gem" do
+    stub_slack_poster_call_with_no_changes
     stub_devdocs_call
     stub_rubygems_call("1.2.3")
     stub_files_changed_since_tag(["README.md"])
 
-    expect { version_checker.print_version_discrepancies }.to output("#platform-security-reliability-team\n\n").to_stdout
+    expect { version_checker.print_version_discrepancies }.to output("team: #platform-security-reliability-team\n").to_stdout
   end
 
   it "detects when there are files changed since the last release that are built into the gem" do
+    stub_slack_poster_call_with_changes
     stub_devdocs_call
     stub_rubygems_call("1.2.2")
     stub_files_changed_since_tag(["lib/foo.rb"])
 
     expect { version_checker.print_version_discrepancies }.to output(
-      "#platform-security-reliability-team\n  example has unreleased changes since v1.2.2\n",
+      "team: #platform-security-reliability-team\n  <https://example.com|example> has unreleased changes since v1.2.2\n",
     ).to_stdout
   end
 
@@ -45,8 +53,36 @@ def stub_rubygems_call(version)
   end
 
   def stub_devdocs_call
-    repo = [{ "app_name": "example", "team": "#platform-security-reliability-team" }]
+    repo = [{ "app_name": "example", "team": "#platform-security-reliability-team", "links": { "repo_url": "https://example.com" } }]
     stub_request(:get, "https://docs.publishing.service.gov.uk/gems.json")
       .to_return(status: 200, body: repo.to_json, headers: {})
   end
+
+  def stub_slack_poster_call_with_changes
+    stub_request(:post, "https://slack/webhook")
+    .with(
+      body: { "payload" => "{\"icon_emoji\":\":gem:\",\"username\":\"Gem Release Bot\",\"channel\":\"#platform-security-reliability-team\",\"text\":\"  <https://example.com|example> has unreleased changes since v1.2.2\"}" },
+      headers: {
+        "Accept" => "*/*",
+        "Accept-Encoding" => "gzip;q=1.0,deflate;q=0.6,identity;q=0.3",
+        "Content-Type" => "application/x-www-form-urlencoded",
+        "User-Agent" => "Faraday v2.7.11",
+      },
+    )
+    .to_return(status: 200, body: "", headers: {})
+  end
+
+  def stub_slack_poster_call_with_no_changes
+    stub_request(:post, "https://slack/webhook")
+         .with(
+           body: { "payload" => "{\"icon_emoji\":\":gem:\",\"username\":\"Gem Release Bot\",\"channel\":\"#platform-security-reliability-team\",\"text\":\"\"}" },
+           headers: {
+             "Accept" => "*/*",
+             "Accept-Encoding" => "gzip;q=1.0,deflate;q=0.6,identity;q=0.3",
+             "Content-Type" => "application/x-www-form-urlencoded",
+             "User-Agent" => "Faraday v2.7.11",
+           },
+         )
+         .to_return(status: 200, body: "", headers: {})
+  end
 end