Verified Commit ef55ba01 authored by Sean McGivern's avatar Sean McGivern 🔴
Browse files

Allow converting a context to headers 

`Labkit::Context#to_headers` works like `#to_h`, but:

1. Excludes the correlation ID (which will already be set in another
   header).
2. Has keys suitable for use in HTTP headers, prefixed with
   `Labkit::Context::HEADER_PREFIX`. Because the keys go through
   `.log_key`, this means it will mostly be `X-Gitlab-Meta-` as a
   prefix.
parent 6cf38f1a

lib/labkit/context.rb

+11 −0
Original line number Diff line number Diff line
@@ -21,6 +21,7 @@ module Labkit 
    LOG_KEY = "meta"

    CORRELATION_ID_KEY = "correlation_id"

    RAW_KEYS = [CORRELATION_ID_KEY].freeze

    HEADER_PREFIX = "X-Gitlab-"

    KNOWN_KEYS = %w[user project root_namespace subscription_plan caller_id

                    related_class feature_category].freeze
@@ -67,6 +68,10 @@ module Labkit 
        @known_log_keys ||= (KNOWN_KEYS.map(&method(:log_key)) + RAW_KEYS).freeze

      end



      def header_name(name)

        HEADER_PREFIX + log_key(name).titlecase(keep_id_suffix: true).gsub(/\W/, "-")

      end



      private



      def contexts
@@ -95,6 +100,12 @@ module Labkit 
      data[CORRELATION_ID_KEY]

    end



    def to_headers

      to_h.except(CORRELATION_ID_KEY).transform_keys do |key|

        self.class.header_name(key)

      end

    end



    protected



    def assign_attributes(attributes)

spec/labkit/context_spec.rb

+45 −0
Original line number Diff line number Diff line
@@ -107,6 +107,25 @@ describe Labkit::Context do 
    end

  end



  describe ".header_name" do

    using RSpec::Parameterized::TableSyntax



    where(:value, :result) do

      :caller_id | "X-Gitlab-Meta-Caller-Id"

      :root_namespace | "X-Gitlab-Meta-Root-Namespace"

      :user | "X-Gitlab-Meta-User"

      :unknown | "X-Gitlab-Meta-Unknown"

      "meta.user" | "X-Gitlab-Meta-User"

      described_class::CORRELATION_ID_KEY | "X-Gitlab-Correlation-Id"

    end



    with_them do

      it do

        expect(described_class.header_name(value)).to eq(result)

      end

    end

  end



  describe "#to_h" do

    let(:expected_hash) do

      log_hash(user: "user",
@@ -159,6 +178,32 @@ describe Labkit::Context do 
    end

  end



  describe "#to_headers" do

    it "returns a hash of header names to values, excluding correlation ID" do

      context = described_class.new(

        user: -> { "user" },

        root_namespace: -> { "namespace" },

        project: -> { "project" },

        caller_id: "ProjectsController#show",

      )



      expect(context.to_headers).to include("X-Gitlab-Meta-User" => "user",

                                            "X-Gitlab-Meta-Root-Namespace" => "namespace",

                                            "X-Gitlab-Meta-Project" => "project",

                                            "X-Gitlab-Meta-Caller-Id" => "ProjectsController#show")

    end



    it "does not include empty values" do

      context = described_class.new(

        user: -> { },

        root_namespace: nil,

        project: "",

      )



      expect(context.to_headers).to be_empty

    end

  end



  describe "#initialize" do

    it "assigns only known keys as strings" do

      context = described_class.new(