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tomasbasham/span_context.rb

Created May 6, 2021 08:45
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  1. tomasbasham created this gist May 6, 2021.
    25 changes: 25 additions & 0 deletions span_context.rb
    View file
    Original file line number Diff line number Diff line change
    @@ -0,0 +1,25 @@
    require 'base64'

    class SpanContext
    def initialize(trace_id: '', span_id: '')
    raise RuntimeError 'trace_id must be 16 bytes' unless trace_id.size == 16
    raise RuntimeError 'span_id must be 8 bytes' unless span_id.size == 8

    @version = [0]
    @trace_id = [0] + trace_id.bytes # field id 0 + trace_id
    @span_id = [1] + span_id.bytes # field id 1 + span_id
    @options = [2, 1] # field id 2 + trace options
    end

    def to_bytes
    @version + @trace_id + @span_id + @options
    end

    def pack
    to_bytes.pack('C*')
    end
    end

    span_context = SpanContext.new(trace_id: '@ABCDEFGHIJKLMNO', span_id: 'abcdefgh')
    print Base64.urlsafe_encode64(span_context.pack, padding: false)
    print "\n"