Add latest changes from gitlab-org/gitlab@master

1 files changed, 130 insertions, 0 deletions

diff --git a/lib/grafana/time_window.rb b/lib/grafana/time_window.rb
new file mode 100644
index 00000000000..111e3ab7de2
--- /dev/null
+++ b/lib/grafana/time_window.rb
@@ -0,0 +1,130 @@
+# frozen_string_literal: true
+
+module Grafana
+  # Allows for easy formatting and manipulations of timestamps
+  # coming from a Grafana url
+  class TimeWindow
+    include ::Gitlab::Utils::StrongMemoize
+
+    def initialize(from, to)
+      @from = from
+      @to = to
+    end
+
+    def formatted
+      {
+        start: window[:from].formatted,
+        end: window[:to].formatted
+      }
+    end
+
+    def in_milliseconds
+      window.transform_values(&:to_ms)
+    end
+
+    private
+
+    def window
+      strong_memoize(:window) do
+        specified_window
+      rescue Timestamp::Error
+        default_window
+      end
+    end
+
+    def specified_window
+      RangeWithDefaults.new(
+        from: Timestamp.from_ms_since_epoch(@from),
+        to: Timestamp.from_ms_since_epoch(@to)
+      ).to_hash
+    end
+
+    def default_window
+      RangeWithDefaults.new.to_hash
+    end
+  end
+
+  # For incomplete time ranges, adds default parameters to
+  # achieve a complete range. If both full range is provided,
+  # range will be returned.
+  class RangeWithDefaults
+    DEFAULT_RANGE = 8.hours
+
+    # @param from [Grafana::Timestamp, nil] Start of the expected range
+    # @param to [Grafana::Timestamp, nil] End of the expected range
+    def initialize(from: nil, to: nil)
+      @from = from
+      @to = to
+
+      apply_defaults!
+    end
+
+    def to_hash
+      { from: @from, to: @to }.compact
+    end
+
+    private
+
+    def apply_defaults!
+      @to ||= @from ? relative_end : Timestamp.new(Time.now)
+      @from ||= relative_start
+    end
+
+    def relative_start
+      Timestamp.new(DEFAULT_RANGE.before(@to.time))
+    end
+
+    def relative_end
+      Timestamp.new(DEFAULT_RANGE.since(@from.time))
+    end
+  end
+
+  # Offers a consistent API for timestamps originating from
+  # Grafana or other sources, allowing for formatting of timestamps
+  # as consumed by Grafana-related utilities
+  class Timestamp
+    Error = Class.new(StandardError)
+
+    attr_accessor :time
+
+    # @param timestamp [Time]
+    def initialize(time)
+      @time = time
+    end
+
+    # Formats a timestamp from Grafana for compatibility with
+    # parsing in JS via `new Date(timestamp)`
+    def formatted
+      time.utc.strftime('%FT%TZ')
+    end
+
+    # Converts to milliseconds since epoch
+    def to_ms
+      time.to_i * 1000
+    end
+
+    class << self
+      # @param time [String] Representing milliseconds since epoch.
+      #                      This is what JS "decided" unix is.
+      def from_ms_since_epoch(time)
+        return if time.nil?
+
+        raise Error.new('Expected milliseconds since epoch') unless ms_since_epoch?(time)
+
+        new(cast_ms_to_time(time))
+      end
+
+      private
+
+      def cast_ms_to_time(time)
+        Time.at(time.to_i / 1000.0)
+      end
+
+      def ms_since_epoch?(time)
+        ms = time.to_i
+
+        ms.to_s == time && ms.bit_length < 64
+      end
+    end
+  end
+end