api: added /version endpoint

With this endpoint clients will be able to fetch:

- Info from the version as stated in the VERSION file.
- Info of the git repository if possible (tag, commit and branch).
- Supported API versions by the server.

Signed-off-by: Miquel Sabaté Solà <msabate@suse.com>

config/initializers/version.rb

@@ -20,6 +20,12 @@ def self.git?
     `git symbolic-ref HEAD 2>/dev/null | cut -d"/" -f 3 2>/dev/null`.chomp
   end
 
+  # Read the version from the file.
+  def self.from_file
+    version = Rails.root.join("VERSION")
+    File.read(version).chomp if File.exist?(version)
+  end
+
   # Version.value returns the app version
   # Priority: git tag > git branch/commit > VERSION file
   def self.value
@@ -32,8 +38,7 @@ def self.value
         COMMIT.to_s
       end
     else
-      version = Rails.root.join("VERSION")
-      File.read(version).chomp if File.exist?(version)
+      Version.from_file
     end
   end
 end

lib/api/root_api.rb

@@ -9,6 +9,7 @@
 require "api/v1/tags"
 require "api/v1/teams"
 require "api/v1/users"
+require "api/version"
 
 module API
   class RootAPI < Grape::API
@@ -52,6 +53,7 @@ class RootAPI < Grape::API
     mount ::API::V1::Tags
     mount ::API::V1::Teams
     mount ::API::V1::Users
+    mount ::API::Version
 
     route :any, "*path" do
       error!("Not found", 404)

lib/api/version.rb

@@ -0,0 +1,28 @@
+module API
+  class Version < Grape::API
+    before do
+      authorization!(force_admin: false)
+    end
+
+    desc "Fetch the version of Portus",
+         tags:   ["version"],
+         detail: "Returns the version of Portus and the supported API versions"
+
+    get "/version" do
+      version = ::Version.from_file
+      git = if ::Version.git?
+        if ::Version::TAG.present?
+          { tag: ::Version::TAG }
+        else
+          { branch: ::Version::BRANCH, commit: ::Version::COMMIT }
+        end
+      end
+
+      {
+        "api-versions": ["v1"],
+        git:            git,
+        version:        version
+      }
+    end
+  end
+end

spec/api/grape_api/v1/version_spec.rb

@@ -0,0 +1,44 @@
+require "rails_helper"
+
+describe API::Version do
+  let!(:admin) { create(:admin) }
+  let!(:token) { create(:application_token, user: admin) }
+
+  before :each do
+    @header = build_token_header(token)
+  end
+
+  context "GET /api/version" do
+    it "returns the proper versioning" do
+      expect(::Version).to receive(:git?).and_return(true)
+
+      get "/api/version", nil, @header
+
+      resp = JSON.parse(response.body)
+      expect(resp["api-versions"]).to eq(["v1"])
+      expect(resp["version"]).to eq(::Version.from_file)
+      expect(resp["git"]).to_not include("tag")
+    end
+
+    it "returns the tag when present" do
+      expect(::Version).to receive(:git?).and_return(true)
+      expect(::Version::TAG).to receive(:present?).and_return(true)
+
+      get "/api/version", nil, @header
+
+      resp = JSON.parse(response.body)
+      expect(resp["git"]).to include("tag")
+    end
+
+    it "returns a null git on stable releases" do
+      expect(::Version).to receive(:git?).and_return(false)
+
+      get "/api/version", nil, @header
+
+      resp = JSON.parse(response.body)
+      expect(resp["api-versions"]).to eq(["v1"])
+      expect(resp["version"]).to eq(::Version.from_file)
+      expect(resp["git"]).to be_nil
+    end
+  end
+end