Add API support for deployment frequency

**app/models/deployment.rb:**
Select deployments that were created within a datetime range.

**ee/app/finders/analytics/deployments_finder.rb:**
Find successful deployments for a project within a datetime range.

**ee/changelogs/unreleased/api-support-for-deployment-frequency.yml:**
Changelog.

**ee/lib/api/analytics/project_deployment_frequency.rb:**
API for getting deployment frequencies for projects.

**ee/lib/ee/api/api.rb:**
Mount the new deployment frequency API.

**ee/lib/ee/api/entities/analytics/deployment_frequency.rb:**
Shape of deployment frequency API responses.

**ee/spec/requests/api/analytics/project_deployment_frequency_spec.rb:**
Test API.

**ee/spec/finders/analytics/deployments_finder_spec.rb:**
Test deployments finder.

**spec/models/deployment_spec.rb:**
Test created_between method.

**doc/user/project/index.md:**
Adds some docs for the new licensed feature flag.

**doc/api/project_analytics.md:**
Adds some docs for the API.

**ee/app/models/license.rb:**
Adds new licensed feature flag for project analytics.

**ee/app/policies/ee/project_policy.rb:**
Adds new policies for the new project analytics feature flag.

**ee/spec/policies/project_policy_spec.rb:**
Test for new project analytics policy and feature flag.

**db/structure.sql:**
**db/migrate/
20201211042306_add_deployments_finder_by_finished_at_index.rb:**
**db/schema_migrations/20201211042306:**

Adding new index to make the deployments finder query fast.

app/models/deployment.rb

@@ -45,6 +45,12 @@ class Deployment < ApplicationRecord
   scope :older_than, -> (deployment) { where('deployments.id < ?', deployment.id) }
   scope :with_deployable, -> { joins('INNER JOIN ci_builds ON ci_builds.id = deployments.deployable_id').preload(:deployable) }
 
+  scope :finished_between, -> (start_date, end_date = nil) do
+    selected = where('deployments.finished_at >= ?', start_date)
+    selected = selected.where('deployments.finished_at < ?', end_date) if end_date
+    selected
+  end
+
   FINISHED_STATUSES = %i[success failed canceled].freeze
 
   state_machine :status, initial: :created do

changelogs/unreleased/api-support-for-deployment-frequency.yml

+---
+title: Add database index on deployments
+merge_request: 48265
+author:
+type: added

db/migrate/20201211042306_add_deployments_finder_by_finished_at_index.rb

+# frozen_string_literal: true
+
+class AddDeploymentsFinderByFinishedAtIndex < ActiveRecord::Migration[6.0]
+  include Gitlab::Database::MigrationHelpers
+
+  DOWNTIME = false
+  INDEX_NAME = "index_deployments_on_project_and_finished"
+
+  disable_ddl_transaction!
+
+  def up
+    add_concurrent_index :deployments,
+      [:project_id, :finished_at],
+      where: 'status = 2',
+      name: INDEX_NAME
+  end
+
+  def down
+    remove_concurrent_index :deployments,
+      [:project_id, :finished_at],
+      where: 'status = 2',
+      name: INDEX_NAME
+  end
+end

db/schema_migrations/20201211042306

+a4d82ca9610a1426bb026c43a00791bcdae38d49ed3ca59285d5a752124a7f20
\ No newline at end of file

db/structure.sql

@@ -21232,6 +21232,8 @@ CREATE INDEX index_deployments_on_id_and_status_and_created_at ON deployments US
 
 CREATE INDEX index_deployments_on_id_where_cluster_id_present ON deployments USING btree (id) WHERE (cluster_id IS NOT NULL);
 
+CREATE INDEX index_deployments_on_project_and_finished ON deployments USING btree (project_id, finished_at) WHERE (status = 2);
+
 CREATE INDEX index_deployments_on_project_id_and_id ON deployments USING btree (project_id, id DESC);
 
 CREATE UNIQUE INDEX index_deployments_on_project_id_and_iid ON deployments USING btree (project_id, iid);

doc/api/project_analytics.md

+---
+stage: Release
+group: Release
+info: To determine the technical writer assigned to the Stage/Group associated with this page, see https://about.gitlab.com/handbook/engineering/ux/technical-writing/#assignments
+type: reference, api
+---
+
+# Project Analytics API **(ULTIMATE ONLY)**
+
+> [Introduced](https://gitlab.com/gitlab-org/gitlab/-/issues/279039) in [GitLab Ultimate](https://about.gitlab.com/pricing/) 13.7.
+
+All methods require reporter authorization.
+
+## List project deployment frequencies
+
+Get a list of all project aliases:
+
+```plaintext
+GET /projects/:id/analytics/deployment_frequency?environment=:environment&from=:from&to=:to&interval=:interval
+```
+
+| Attribute    | Type   | Required | Description           |
+|--------------|--------|----------|-----------------------|
+| `id`         | string | yes      | The ID of the project |
+
+| Parameter    | Type   | Required | Description           |
+|--------------|--------|----------|-----------------------|
+| `environment`| string | yes      | The name of the environment to filter by |
+| `from`       | string | yes      | Datetime range to start from, inclusive, ISO 8601 format (`YYYY-MM-DDTHH:MM:SSZ`) |
+| `to`         | string | no       | Datetime range to end at, exclusive, ISO 8601 format (`YYYY-MM-DDTHH:MM:SSZ`) |
+| `interval`   | string | no       | The bucketing interval (`all`, `monthly`, `daily`) |
+
+```shell
+curl --header "PRIVATE-TOKEN: <your_access_token>" "https://gitlab.example.com/api/v4/projects/:id/analytics/deployment_frequency?from=:from&to=:to&interval=:interval"
+```
+
+Example response:
+
+```json
+[
+  {
+    "from": "2017-01-01",
+    "to": "2017-01-02",
+    "value": 106
+  },
+  {
+    "from": "2017-01-02",
+    "to": "2017-01-03",
+    "value": 55
+  }
+]
+```

doc/user/project/index.md

@@ -374,6 +374,16 @@ project `https://gitlab.com/gitlab-org/gitlab`), the repository can be cloned
 using the alias (e.g `git clone git@gitlab.com:gitlab.git` instead of
 `git clone git@gitlab.com:gitlab-org/gitlab.git`).
 
+## Project activity analytics overview **(ULTIMATE ONLY)**
+
+> [Introduced](https://gitlab.com/gitlab-org/gitlab/-/issues/279039) in GitLab [Ultimate](https://about.gitlab.com/pricing/) 13.7 as a [Beta feature](https://about.gitlab.com/handbook/product/gitlab-the-product/#beta).
+
+Project details include the following analytics:
+
+- Deployment Frequency
+
+For more information, see [Project Analytics API](../../api/project_analytics.md).
+
 ## Project APIs
 
 There are numerous [APIs](../../api/README.md) to use with your projects:
@@ -394,3 +404,4 @@ There are numerous [APIs](../../api/README.md) to use with your projects:
 - [Traffic](../../api/project_statistics.md)
 - [Variables](../../api/project_level_variables.md)
 - [Aliases](../../api/project_aliases.md)
+- [Analytics](../../api/project_analytics.md)

ee/app/finders/analytics/deployments_finder.rb

+# frozen_string_literal: true
+
+module Analytics
+  class DeploymentsFinder
+    def initialize(project:, environment_name:, from:, to: nil)
+      @project = project
+      @environment_name = environment_name
+      @from = from
+      @to = to
+    end
+
+    attr_reader :project, :environment_name, :from, :to
+
+    def execute
+      filter_deployments(project.deployments)
+    end
+
+    private
+
+    def filter_deployments(all_deployments)
+      deployments = filter_by_time(all_deployments)
+      deployments = filter_by_success(deployments)
+      deployments = filter_by_environment_name(deployments)
+      # rubocop: disable CodeReuse/ActiveRecord
+      deployments = deployments.order('finished_at')
+      # rubocop: enable CodeReuse/ActiveRecord
+      deployments
+    end
+
+    def filter_by_time(deployments)
+      deployments.finished_between(from, to)
+    end
+
+    def filter_by_success(deployments)
+      deployments.success
+    end
+
+    def filter_by_environment_name(deployments)
+      deployments.for_environment_name(environment_name)
+    end
+  end
+end

ee/app/models/license.rb

@@ -132,27 +132,29 @@ class License < ApplicationRecord
   EEP_FEATURES.freeze
 
   EEU_FEATURES = EEP_FEATURES + %i[
+    api_fuzzing
     auto_rollback
+    cilium_alerts
     container_scanning
     coverage_fuzzing
     credentials_inventory
-    cilium_alerts
     dast
     dependency_scanning
     devops_adoption
+    enforce_pat_expiration
     enterprise_templates
-    api_fuzzing
+    environment_alerts
     group_level_compliance_dashboard
     incident_management
     insights
     issuable_health_status
     license_scanning
     personal_access_token_expiration_policy
-    enforce_pat_expiration
+    project_activity_analytics
     prometheus_alerts
     pseudonymizer
+    quality_management
     release_evidence_test_artifacts
-    environment_alerts
     report_approver_rules
     requirements
     sast
@@ -164,7 +166,6 @@ class License < ApplicationRecord
     subepics
     threat_monitoring
     vulnerability_auto_fix
-    quality_management
   ]
   EEU_FEATURES.freeze
 

ee/app/policies/ee/project_policy.rb

@@ -54,6 +54,11 @@ module EE
           ::Gitlab::CurrentSettings.prevent_merge_requests_committers_approval
       end
 
+      with_scope :subject
+      condition(:project_activity_analytics_available) do
+        @subject.feature_available?(:project_activity_analytics)
+      end
+
       condition(:project_merge_request_analytics_available) do
         @subject.feature_available?(:project_merge_request_analytics)
       end
@@ -351,6 +356,9 @@ module EE
 
       rule { can?(:read_merge_request) & code_review_analytics_enabled }.enable :read_code_review_analytics
 
+      rule { reporter & project_activity_analytics_available }
+        .enable :read_project_activity_analytics
+
       rule { reporter & project_merge_request_analytics_available }
         .enable :read_project_merge_request_analytics
 

ee/changelogs/unreleased/api-support-for-deployment-frequency.yml

+---
+title: Adds API support for Project Deployment Frequency
+merge_request: 48265
+author:
+type: added

ee/lib/api/analytics/project_deployment_frequency.rb

+# frozen_string_literal: true
+
+module API
+  module Analytics
+    class ProjectDeploymentFrequency < ::API::Base
+      include Gitlab::Utils::StrongMemoize
+      include PaginationParams
+
+      QUARTER_DAYS = 3.months / 1.day
+      DEPLOYMENT_FREQUENCY_INTERVAL_ALL = 'all'.freeze
+      DEPLOYMENT_FREQUENCY_INTERVAL_MONTHLY = 'monthly'.freeze
+      DEPLOYMENT_FREQUENCY_INTERVAL_DAILY = 'daily'.freeze
+      DEPLOYMENT_FREQUENCY_DEFAULT_INTERVAL = DEPLOYMENT_FREQUENCY_INTERVAL_ALL
+      VALID_INTERVALS = [
+        DEPLOYMENT_FREQUENCY_INTERVAL_ALL,
+        DEPLOYMENT_FREQUENCY_INTERVAL_MONTHLY,
+        DEPLOYMENT_FREQUENCY_INTERVAL_DAILY
+      ].freeze
+
+      feature_category :planning_analytics
+
+      before do
+        authenticate!
+      end
+
+      helpers do
+        def environment_name
+          params[:environment]
+        end
+
+        def start_date
+          params[:from]
+        end
+
+        def end_date
+          params[:to] || DateTime.current
+        end
+
+        def days_between
+          (end_date - start_date).to_i
+        end
+
+        def interval
+          params[:interval] || DEPLOYMENT_FREQUENCY_DEFAULT_INTERVAL
+        end
+
+        def deployments
+          strong_memoize(:deployments) do
+            ::Analytics::DeploymentsFinder.new(
+              project: user_project,
+              environment_name: environment_name,
+              from: start_date,
+              to: end_date
+            ).execute
+          end
+        end
+
+        def deployments_grouped
+          strong_memoize(:deployments_grouped) do
+            case interval
+            when DEPLOYMENT_FREQUENCY_INTERVAL_ALL
+              { start_date => deployments }
+            when DEPLOYMENT_FREQUENCY_INTERVAL_MONTHLY
+              deployments.group_by { |d| d.finished_at.beginning_of_month }
+            when DEPLOYMENT_FREQUENCY_INTERVAL_DAILY
+              deployments.group_by { |d| d.finished_at.to_date }
+            end
+          end
+        end
+
+        def deployments_grouped_end_date(deployments_grouped_start_date)
+          case interval
+          when DEPLOYMENT_FREQUENCY_INTERVAL_ALL
+            end_date
+          when DEPLOYMENT_FREQUENCY_INTERVAL_MONTHLY
+            deployments_grouped_start_date + 1.month
+          when DEPLOYMENT_FREQUENCY_INTERVAL_DAILY
+            deployments_grouped_start_date + 1.day
+          end
+        end
+
+        def deployment_frequencies
+          strong_memoize(:deployment_frequencies) do
+            deployments_grouped.map do |grouped_start_date, grouped_deploys|
+              {
+                value: grouped_deploys.count,
+                from: grouped_start_date,
+                to: deployments_grouped_end_date(grouped_start_date)
+              }
+            end
+          end
+        end
+      end
+
+      params do
+        requires :id, type: String, desc: 'The ID of the project'
+      end
+
+      resource :projects, requirements: API::NAMESPACE_OR_PROJECT_REQUIREMENTS do
+        namespace ':id/analytics' do
+          desc 'List analytics for the project'
+
+          params do
+            requires :environment, type: String, desc: 'Name of the environment to filter by'
+            requires :from, type: DateTime, desc: 'Datetime to start from, inclusive'
+            optional :to, type: DateTime, desc: 'Datetime to end at, exclusive'
+            optional :interval, type: String, desc: 'Interval to roll-up data by', values: VALID_INTERVALS
+            use :pagination
+          end
+
+          get 'deployment_frequency' do
+            bad_request!("Parameter `to` is before the `from` date") if start_date > end_date
+            bad_request!("Date range is greater than #{QUARTER_DAYS} days") if days_between > QUARTER_DAYS
+            authorize! :read_project_activity_analytics, user_project
+            present paginate(::Kaminari.paginate_array(deployment_frequencies)),
+                    with: EE::API::Entities::Analytics::DeploymentFrequency
+          end
+        end
+      end
+    end
+  end
+end

ee/lib/ee/api/api.rb

@@ -42,6 +42,7 @@ module EE
         mount ::API::VisualReviewDiscussions
         mount ::API::Analytics::CodeReviewAnalytics
         mount ::API::Analytics::GroupActivityAnalytics
+        mount ::API::Analytics::ProjectDeploymentFrequency
         mount ::API::ProtectedEnvironments
         mount ::API::ResourceWeightEvents
         mount ::API::ResourceIterationEvents

ee/lib/ee/api/entities/analytics/deployment_frequency.rb

+# frozen_string_literal: true
+
+module EE
+  module API
+    module Entities
+      module Analytics
+        class DeploymentFrequency < Grape::Entity
+          expose :value
+          expose :from
+          expose :to
+        end
+      end
+    end
+  end
+end

ee/spec/finders/analytics/deployments_finder_spec.rb

+# frozen_string_literal: true
+
+require 'spec_helper'
+
+RSpec.describe Analytics::DeploymentsFinder do
+  let_it_be(:project) { create(:project, :repository) }
+  let_it_be(:prod) { create(:environment, project: project, name: "prod") }
+  let_it_be(:dev) { create(:environment, project: project, name: "dev") }
+  let_it_be(:other_project) { create(:project, :repository) }
+  let_it_be(:start_time) { DateTime.new(2017) }
+  let_it_be(:end_time) { DateTime.new(2019) }
+
+  def make_deployment(finished_at, env)
+    create(:deployment,
+           status: :success,
+           project: project,
+           environment: env,
+           finished_at: finished_at)
+  end
+
+  let_it_be(:deployment_2016) { make_deployment(DateTime.new(2016), prod) }
+  let_it_be(:deployment_2017) { make_deployment(DateTime.new(2017), prod) }
+  let_it_be(:deployment_2018) { make_deployment(DateTime.new(2018), prod) }
+  let_it_be(:dev_deployment_2018) { make_deployment(DateTime.new(2018), dev) }
+  let_it_be(:deployment_2019) { make_deployment(DateTime.new(2019), prod) }
+  let_it_be(:deployment_2020) { make_deployment(DateTime.new(2020), prod) }
+
+  describe '#execute' do
+    it 'returns successful deployments for the given project and datetime range' do
+      travel_to(start_time) do
+        create(:deployment, status: :running, project: project, environment: prod)
+        create(:deployment, status: :failed, project: project, environment: prod)
+        create(:deployment, status: :canceled, project: project, environment: prod)
+        create(:deployment, status: :skipped, project: project, environment: prod)
+        create(:deployment, status: :success, project: other_project, environment: prod)
+        create(:deployment, status: :success, project: other_project, environment: prod)
+      end
+
+      expect(described_class.new(
+        project: project,
+        environment_name: prod.name,
+        from: start_time,
+        to: end_time
+      ).execute).to contain_exactly(deployment_2017, deployment_2018)
+
+      expect(described_class.new(
+        project: project,
+        environment_name: prod.name,
+        from: start_time
+      ).execute).to contain_exactly(
+        deployment_2017,
+        deployment_2018,
+        deployment_2019,
+        deployment_2020
+      )
+
+      expect(described_class.new(
+        project: project,
+        environment_name: dev.name,
+        from: start_time
+      ).execute).to contain_exactly(dev_deployment_2018)
+    end
+  end
+end

ee/spec/policies/project_policy_spec.rb

@@ -1221,6 +1221,26 @@ RSpec.describe ProjectPolicy do
     it { is_expected.to be_disallowed(:read_group_timelogs) }
   end
 
+  context 'when project activity analytics is available' do
+    let(:current_user) { developer }
+
+    before do
+      stub_licensed_features(project_activity_analytics: true)
+    end
+
+    it { is_expected.to be_allowed(:read_project_activity_analytics) }
+  end
+
+  context 'when project activity analytics is not available' do
+    let(:current_user) { developer }
+
+    before do
+      stub_licensed_features(project_activity_analytics: false)
+    end
+
+    it { is_expected.not_to be_allowed(:read_project_activity_analytics) }
+  end
+
   describe ':read_code_review_analytics' do
     let(:project) { private_project }
 

ee/spec/requests/api/analytics/project_deployment_frequency_spec.rb

+# frozen_string_literal: true
+
+require 'spec_helper'
+
+RSpec.describe API::Analytics::ProjectDeploymentFrequency do
+  let_it_be(:group) { create(:group, :private) }
+  let_it_be(:project) { create(:project, :repository, namespace: group) }
+  let_it_be(:prod) { create(:environment, project: project, name: "prod") }
+  let_it_be(:dev) { create(:environment, project: project, name: "dev") }
+  let_it_be(:anonymous_user) { create(:user) }
+  let_it_be(:reporter) { create(:user).tap { |u| project.add_reporter(u) } }
+
+  def make_deployment(finished_at, env)
+    create(:deployment,
+           status: :success,
+           project: project,
+           environment: env,
+           finished_at: finished_at)
+  end
+
+  let_it_be(:deployment_2020_01_01) { make_deployment(DateTime.new(2020, 1, 1), prod) }
+  let_it_be(:deployment_2020_01_02) { make_deployment(DateTime.new(2020, 1, 2), prod) }
+  let_it_be(:deployment_2020_01_03) { make_deployment(DateTime.new(2020, 1, 3), dev) }
+  let_it_be(:deployment_2020_01_04) { make_deployment(DateTime.new(2020, 1, 4), prod) }
+  let_it_be(:deployment_2020_01_05) { make_deployment(DateTime.new(2020, 1, 5), prod) }
+
+  let_it_be(:deployment_2020_02_01) { make_deployment(DateTime.new(2020, 2, 1), prod) }
+  let_it_be(:deployment_2020_02_02) { make_deployment(DateTime.new(2020, 2, 2), prod) }
+  let_it_be(:deployment_2020_02_03) { make_deployment(DateTime.new(2020, 2, 3), dev) }
+  let_it_be(:deployment_2020_02_04) { make_deployment(DateTime.new(2020, 2, 4), prod) }
+  let_it_be(:deployment_2020_02_05) { make_deployment(DateTime.new(2020, 2, 5), prod) }
+
+  let_it_be(:deployment_2020_03_01) { make_deployment(DateTime.new(2020, 3, 1), prod) }
+  let_it_be(:deployment_2020_03_02) { make_deployment(DateTime.new(2020, 3, 2), prod) }
+  let_it_be(:deployment_2020_03_03) { make_deployment(DateTime.new(2020, 3, 3), dev) }
+  let_it_be(:deployment_2020_03_04) { make_deployment(DateTime.new(2020, 3, 4), prod) }
+  let_it_be(:deployment_2020_03_05) { make_deployment(DateTime.new(2020, 3, 5), prod) }
+
+  let_it_be(:deployment_2020_04_01) { make_deployment(DateTime.new(2020, 4, 1), prod) }
+  let_it_be(:deployment_2020_04_02) { make_deployment(DateTime.new(2020, 4, 2), prod) }
+  let_it_be(:deployment_2020_04_03) { make_deployment(DateTime.new(2020, 4, 3), dev) }
+  let_it_be(:deployment_2020_04_04) { make_deployment(DateTime.new(2020, 4, 4), prod) }
+  let_it_be(:deployment_2020_04_05) { make_deployment(DateTime.new(2020, 4, 5), prod) }
+
+  let(:project_activity_analytics_enabled) { true }
+  let(:current_user) { reporter }
+  let(:params) { { from: Time.now, to: Time.now, interval: "all", environment: prod.name } }
+  let(:path) { api("/projects/#{project.id}/analytics/deployment_frequency", current_user) }
+  let(:request) { get path, params: params }
+  let(:request_time) { nil }
+
+  before do
+    stub_licensed_features(project_activity_analytics: project_activity_analytics_enabled)
+
+    if request_time
+      travel_to(request_time) { request }
+    else
+      request
+    end
+  end
+
+  context 'when user has access to the project' do
+    it 'returns `ok`' do
+      expect(response).to have_gitlab_http_status(:ok)
+    end
+  end
+
+  context 'with params: from 2017 to 2019' do
+    let(:params) { { environment: prod.name, from: DateTime.new(2017), to: DateTime.new(2019) } }
+
+    it 'returns `bad_request` with expected message' do
+      expect(response.parsed_body).to eq({
+        "message" => "400 (Bad request) \"Date range is greater than 91 days\" not given"
+      })
+    end
+  end
+
+  context 'with params: from 2019 to 2017' do
+    let(:params) do
+      { environment: prod.name, from: DateTime.new(2019), to: DateTime.new(2017) }
+    end
+
+    it 'returns `bad_request` with expected message' do
+      expect(response.parsed_body).to eq({
+        "message" => "400 (Bad request) \"Parameter `to` is before the `from` date\" not given"
+      })
+    end
+  end
+
+  context 'with params: from 2020/04/01 to request time' do
+    let(:request_time) { DateTime.new(2020, 4, 4) }
+    let(:params) { { environment: prod.name, from: DateTime.new(2020, 4, 2) } }
+
+    it 'returns the expected deployment frequencies' do
+      expect(response.parsed_body).to eq([{
+        "from" => "2020-04-02T00:00:00.000+00:00",
+        "to" => "2020-04-04T00:00:00.000+00:00",
+        "value" => 1
+      }])
+    end
+  end
+
+  context 'with params: from 2020/02/01 to 2020/04/01 by all' do
+    let(:params) do
+      {
+        environment: prod.name,
+        from: DateTime.new(2020, 2, 1),
+        to: DateTime.new(2020, 4, 1),
+        interval: "all"
+      }
+    end
+
+    it 'returns the expected deployment frequencies' do
+      expect(response.parsed_body).to eq([{
+          "from" => "2020-02-01T00:00:00.000+00:00",
+          "to" => "2020-04-01T00:00:00.000+00:00",
+          "value" => 8
+        }])
+    end
+  end
+
+  context 'with params: from 2020/02/01 to 2020/04/01 by month' do
+    let(:params) do
+      {
+        environment: prod.name,
+        from: DateTime.new(2020, 2, 1),
+        to: DateTime.new(2020, 4, 1),
+        interval: "monthly"
+      }
+    end
+
+    it 'returns the expected deployment frequencies' do
+      expect(response.parsed_body).to eq([
+        { "from" => "2020-02-01T00:00:00.000Z", "to" => "2020-03-01T00:00:00.000Z", "value" => 4 },
+        { "from" => "2020-03-01T00:00:00.000Z", "to" => "2020-04-01T00:00:00.000Z", "value" => 4 }
+      ])
+    end
+  end
+
+  context 'with params: from 2017 to 2019 by day' do
+    let(:params) do
+      {
+        environment: prod.name,
+        from: DateTime.new(2020, 2, 1),
+        to: DateTime.new(2020, 4, 1),
+        interval: "daily"
+      }
+    end
+
+    it 'returns the expected deployment frequencies' do
+      expect(response.parsed_body).to eq([
+        { "from" => "2020-02-01", "to" => "2020-02-02", "value" => 1 },
+        { "from" => "2020-02-02", "to" => "2020-02-03", "value" => 1 },
+        { "from" => "2020-02-04", "to" => "2020-02-05", "value" => 1 },
+        { "from" => "2020-02-05", "to" => "2020-02-06", "value" => 1 },
+        { "from" => "2020-03-01", "to" => "2020-03-02", "value" => 1 },
+        { "from" => "2020-03-02", "to" => "2020-03-03", "value" => 1 },
+        { "from" => "2020-03-04", "to" => "2020-03-05", "value" => 1 },
+        { "from" => "2020-03-05", "to" => "2020-03-06", "value" => 1 }
+      ])
+    end
+  end
+
+  context 'with params: invalid interval' do
+    let(:params) do
+      {
+        environment: prod.name,
+        from: DateTime.new(2020, 1),
+        to: DateTime.new(2020, 2),
+        interval: "invalid"
+      }
+    end
+
+    it 'returns `bad_request`' do
+      expect(response).to have_gitlab_http_status(:bad_request)
+    end
+  end
+
+  context 'with params: missing from' do
+    let(:params) { { environment: prod.name, to: DateTime.new(2019), interval: "all" } }
+
+    it 'returns `bad_request`' do
+      expect(response).to have_gitlab_http_status(:bad_request)
+    end
+  end
+
+  context 'when user does not have access to the project' do
+    let(:current_user) { anonymous_user }
+
+    it 'returns `not_found`' do
+      expect(response).to have_gitlab_http_status(:not_found)
+    end
+  end
+
+  context 'when feature is not available in plan' do
+    let(:project_activity_analytics_enabled) { false }
+
+    context 'when user has access to the project' do
+      it 'returns `forbidden`' do
+        expect(response).to have_gitlab_http_status(:forbidden)
+      end
+    end
+
+    context 'when user does not have access to the project' do
+      let(:current_user) { anonymous_user }
+
+      it 'returns `not_found`' do
+        expect(response).to have_gitlab_http_status(:not_found)
+      end
+    end
+  end
+end

spec/models/deployment_spec.rb

@@ -378,6 +378,22 @@ RSpec.describe Deployment do
       end
     end
 
+    describe 'finished_between' do
+      subject { described_class.finished_between(start_time, end_time) }
+
+      let_it_be(:start_time) { DateTime.new(2017) }
+      let_it_be(:end_time) { DateTime.new(2019) }
+      let_it_be(:deployment_2016) { create(:deployment, finished_at: DateTime.new(2016)) }
+      let_it_be(:deployment_2017) { create(:deployment, finished_at: DateTime.new(2017)) }
+      let_it_be(:deployment_2018) { create(:deployment, finished_at: DateTime.new(2018)) }
+      let_it_be(:deployment_2019) { create(:deployment, finished_at: DateTime.new(2019)) }
+      let_it_be(:deployment_2020) { create(:deployment, finished_at: DateTime.new(2020)) }
+
+      it 'retrieves deployments that finished between the specified times' do
+        is_expected.to contain_exactly(deployment_2017, deployment_2018)
+      end
+    end
+
     describe 'visible' do
       subject { described_class.visible }