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fix: Enforce baggage limits on the Jaeger extract path #2299

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fix: Enforce baggage limits on the Jaeger extract path #2299

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e8112ad
fix: Enforce baggage limits on the Jaeger extract path
serhiy-bzhezytskyy Aug 18, 2026
c0c2ec6
Trim the comments on the Jaeger baggage caps
serhiy-bzhezytskyy Aug 18, 2026
406be37
Skip Jaeger baggage headers that carry no value
serhiy-bzhezytskyy Aug 18, 2026
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24 changes: 19 additions & 5 deletions propagator/jaeger/lib/opentelemetry/propagator/jaeger/text_map_propagator.rb
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Original file line number Diff line number Diff line change
Expand Up @@ -26,10 +26,15 @@ class TextMapPropagator
FIELDS = [IDENTITY_KEY].freeze
TRACE_SPAN_IDENTITY_REGEX = /\A(?<trace_id>(?:[0-9a-f]){1,32}):(?<span_id>(?:[0-9a-f]){1,16}):(?:[0-9a-f]){1,16}:(?<sampling_flags>[0-9a-f]{1,2})\z/
ZERO_ID_REGEX = /^0+$/
BAGGAGE_KEY_PREFIX = 'uberctx-'
MAX_BAGGAGE_ENTRIES = 180
MAX_BAGGAGE_ENTRY_BYTES = 4096
MAX_BAGGAGE_TOTAL_BYTES = 8192

private_constant \
:IDENTITY_KEY, :DEFAULT_FLAG_BIT, :SAMPLED_FLAG_BIT, :DEBUG_FLAG_BIT,
:FIELDS, :TRACE_SPAN_IDENTITY_REGEX, :ZERO_ID_REGEX
:FIELDS, :TRACE_SPAN_IDENTITY_REGEX, :ZERO_ID_REGEX, :BAGGAGE_KEY_PREFIX,
:MAX_BAGGAGE_ENTRIES, :MAX_BAGGAGE_ENTRY_BYTES, :MAX_BAGGAGE_TOTAL_BYTES

# Extract trace context from the supplied carrier.
# If extraction fails, the original context will be returned
Expand Down Expand Up @@ -103,15 +108,24 @@ def build_span(match, sampling_flags)
end

def context_with_extracted_baggage(carrier, context, getter)
baggage_key_prefix = 'uberctx-'
OpenTelemetry::Baggage.build(context: context) do |b|
count = 0
total_bytes = 0
getter.keys(carrier).each do |carrier_key|
baggage_key = carrier_key.start_with?(baggage_key_prefix) && carrier_key[baggage_key_prefix.length..]
break unless count < MAX_BAGGAGE_ENTRIES

baggage_key = carrier_key.start_with?(BAGGAGE_KEY_PREFIX) && carrier_key[BAGGAGE_KEY_PREFIX.length..]
next unless baggage_key

raw_value = getter.get(carrier, carrier_key)

@xuan-cao-swi xuan-cao-swi Aug 18, 2026

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Maybe add next unless raw_value to ignore the case when raw_value=nil?
This can also prevent the undefined method 'bytesize' issue when raw_value is nil

@serhiy-bzhezytskyy serhiy-bzhezytskyy Aug 18, 2026

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Thanks, you're right. Fixed and covered it with a test.

Rubocop then hit 8/7 on Metrics/CyclomaticComplexity and 101/100 on Metrics/ClassLength, so the limit check moved into within_baggage_limits? and the private_constant list is reflowed. bundle exec rake is green.

value = URI.decode_uri_component(raw_value)
b.set_value(baggage_key, value)
# Limits are byte-denominated, not character-denominated.
entry_bytes = baggage_key.bytesize + raw_value.bytesize
next unless entry_bytes <= MAX_BAGGAGE_ENTRY_BYTES &&
total_bytes + entry_bytes <= MAX_BAGGAGE_TOTAL_BYTES

b.set_value(baggage_key, URI.decode_uri_component(raw_value))
count += 1
total_bytes += entry_bytes
end
end
end
Expand Down
43 changes: 43 additions & 0 deletions propagator/jaeger/test/text_map_propagator_test.rb
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Original file line number Diff line number Diff line change
Expand Up @@ -140,6 +140,49 @@ def extracted_context_must_equal_parent_context(header)
_(OpenTelemetry::Baggage.value('key-2', context: context)).must_equal('value2')
end

it 'enforces the max of 180 baggage entries, keeping the first ones' do
carrier = { 'uber-trace-id' => '80f198ee56343ba864fe8b2a57d3eff7:e457b5a2e4d86bd1:0:1' }
200.times { |i| carrier["uberctx-k#{i}"] = "v#{i}" }
context = propagator.extract(carrier, context: OpenTelemetry::Context.empty)
_(OpenTelemetry::Baggage.values(context: context).size).must_equal(180)
_(OpenTelemetry::Baggage.value('k0', context: context)).must_equal('v0')
_(OpenTelemetry::Baggage.value('k180', context: context)).must_be_nil
end

it 'drops a baggage entry over 4096 bytes, keeping the rest' do
carrier = {
'uber-trace-id' => '80f198ee56343ba864fe8b2a57d3eff7:e457b5a2e4d86bd1:0:1',
'uberctx-ok' => 'value',
'uberctx-big' => 'x' * 5000
}
context = propagator.extract(carrier, context: OpenTelemetry::Context.empty)
_(OpenTelemetry::Baggage.value('ok', context: context)).must_equal('value')
_(OpenTelemetry::Baggage.value('big', context: context)).must_be_nil
end

it 'measures the per-entry limit in bytes, not characters' do
carrier = {
'uber-trace-id' => '80f198ee56343ba864fe8b2a57d3eff7:e457b5a2e4d86bd1:0:1',
'uberctx-ok' => 'value',
# 2100 multibyte chars = 4200 bytes: under 4096 chars, over 4096 bytes
'uberctx-u' => 'é' * 2100
}
context = propagator.extract(carrier, context: OpenTelemetry::Context.empty)
_(OpenTelemetry::Baggage.value('ok', context: context)).must_equal('value')
_(OpenTelemetry::Baggage.value('u', context: context)).must_be_nil
end

it 'enforces the max total of 8192 bytes, keeping the earlier entries' do
carrier = { 'uber-trace-id' => '80f198ee56343ba864fe8b2a57d3eff7:e457b5a2e4d86bd1:0:1' }
100.times { |i| carrier["uberctx-k#{i}"] = 'y' * 200 } # ~100 * ~205 bytes = ~20k
context = propagator.extract(carrier, context: OpenTelemetry::Context.empty)
size = OpenTelemetry::Baggage.values(context: context).size
_(size).must_be(:positive?)
_(size).must_be(:<, 100)
_(OpenTelemetry::Baggage.value('k0', context: context)).wont_be_nil
_(OpenTelemetry::Baggage.value('k99', context: context)).must_be_nil
end

it 'handles trace ids and span ids that are too long' do
extracted_context_must_equal_parent_context(
'80f198ee56343ba864fe8b2a57d3eff7eff7:e457b5a2e4d86bd1:0:1'
Expand Down