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feat(zipkin) new header_type config option
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@kikito
kikito committed Apr 22, 2020
1 parent 7c278a8 commit c2e5676
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Showing 7 changed files with 655 additions and 374 deletions.
2 changes: 1 addition & 1 deletion kong-plugin-zipkin-1.0.0-1.rockspec
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Original file line number Diff line number Diff line change
Expand Up @@ -24,7 +24,7 @@ build = {
["kong.plugins.zipkin.handler"] = "kong/plugins/zipkin/handler.lua",
["kong.plugins.zipkin.reporter"] = "kong/plugins/zipkin/reporter.lua",
["kong.plugins.zipkin.span"] = "kong/plugins/zipkin/span.lua",
["kong.plugins.zipkin.parse_http_req_headers"] = "kong/plugins/zipkin/parse_http_req_headers.lua",
["kong.plugins.zipkin.tracing_headers"] = "kong/plugins/zipkin/tracing_headers.lua",
["kong.plugins.zipkin.schema"] = "kong/plugins/zipkin/schema.lua",
},
}
36 changes: 5 additions & 31 deletions kong/plugins/zipkin/handler.lua
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Original file line number Diff line number Diff line change
@@ -1,9 +1,7 @@
local new_zipkin_reporter = require "kong.plugins.zipkin.reporter".new
local new_span = require "kong.plugins.zipkin.span".new
local to_hex = require "resty.string".to_hex
local parse_http_req_headers = require "kong.plugins.zipkin.parse_http_req_headers"
local utils = require "kong.tools.utils"

local tracing_headers = require "kong.plugins.zipkin.tracing_headers"

local subsystem = ngx.config.subsystem
local fmt = string.format
Expand Down Expand Up @@ -104,8 +102,8 @@ if subsystem == "http" then
initialize_request = function(conf, ctx)
local req = kong.request

local trace_id, span_id, parent_id, should_sample, baggage =
parse_http_req_headers(req.get_headers())
local header_type, trace_id, span_id, parent_id, should_sample, baggage =
tracing_headers.parse(req.get_headers())
local method = req.get_method()

if should_sample == nil then
Expand Down Expand Up @@ -135,6 +133,7 @@ if subsystem == "http" then

ctx.zipkin = {
request_span = request_span,
header_type = header_type,
proxy_span = nil,
header_filter_finished = false,
}
Expand All @@ -161,32 +160,7 @@ if subsystem == "http" then
or ngx_now_mu()
get_or_add_proxy_span(zipkin, access_start)

-- Want to send headers to upstream
local proxy_span = zipkin.proxy_span
local set_header = kong.service.request.set_header

-- Set the W3C Trace Context header
-- TODO: Should W3C traceparent header be set even it wasn't on the incoming request?
set_header("traceparent", "00-".. to_hex(proxy_span.trace_id) .. "-" .. to_hex(proxy_span.span_id) .. "-" ..
tostring(proxy_span.should_sample and "01" or "00"))

-- TODO: Should B3 headers be set even if they weren't on the incoming request?
-- We want to remove headers if already present
set_header("x-b3-traceid", to_hex(proxy_span.trace_id))
set_header("x-b3-spanid", to_hex(proxy_span.span_id))
if proxy_span.parent_id then
set_header("x-b3-parentspanid", to_hex(proxy_span.parent_id))
end
local Flags = kong.request.get_header("x-b3-flags") -- Get from request headers
if Flags then
set_header("x-b3-flags", Flags)
else
set_header("x-b3-sampled", proxy_span.should_sample and "1" or "0")
end
for key, value in proxy_span:each_baggage_item() do
-- XXX: https://github.com/opentracing/specification/issues/117
set_header("uberctx-"..key, ngx.escape_uri(value))
end
tracing_headers.set(conf.header_type, zipkin.header_type, zipkin.proxy_span)
end


Expand Down
2 changes: 2 additions & 0 deletions kong/plugins/zipkin/schema.lua
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Original file line number Diff line number Diff line change
Expand Up @@ -13,6 +13,8 @@ return {
{ default_service_name = { type = "string", default = nil } },
{ include_credential = { type = "boolean", required = true, default = true } },
{ traceid_byte_count = { type = "integer", required = true, default = 16, one_of = { 8, 16 } } },
{ header_type = { type = "string", required = true, default = "preserve",
one_of = { "preserve", "b3", "b3-single", "w3c" } } },
},
}, },
},
Expand Down
160 changes: 122 additions & 38 deletions ...plugins/zipkin/parse_http_req_headers.lua → kong/plugins/zipkin/tracing_headers.lua
View file
Original file line number Diff line number Diff line change
@@ -1,7 +1,10 @@
local to_hex = require "resty.string".to_hex

local unescape_uri = ngx.unescape_uri
local char = string.char
local match = string.match
local gsub = string.gsub
local fmt = string.format


local baggage_mt = {
Expand Down Expand Up @@ -47,7 +50,7 @@ local function parse_jaeger_baggage_headers(headers)
end


local function parse_zipkin_b3_headers(headers)
local function parse_zipkin_b3_headers(headers, b3_single_header)
local warn = kong.log.warn

-- X-B3-Sampled: if an upstream decided to sample this request, we do too.
Expand All @@ -74,28 +77,10 @@ local function parse_zipkin_b3_headers(headers)
local had_invalid_id = false

-- B3 single header
-- The docs for this header are located here:
-- https://github.com/openzipkin/b3-propagation/blob/master/RATIONALE.md#b3-single-header-format
--
-- This code makes some assumptions about edge cases not covered on those docs:
-- * X-B3-Sampled and X-B3-Flags can be used in conjunction with B3 single. This doesn't raise any errors.
-- * The id headers (X-B3-TraceId, X-B3-SpanId, X-B3-ParentId) can also be used along with B3 but:
-- * When both the single header an a id header specify an id, the single header "wins" (overrides)
-- * All provided id headers are parsed (even those overriden by B3 single)
-- * An erroneous formatting on *any* header (even those overriden by B3 single) results
-- in rejection (ignoring) of all headers. This rejection is logged.
-- * The "sampled" section activates sampling with both "1" and "d". This is to match the
-- behavior of the X-B3-Flags header
-- * For speed, the "-" separators between sampled and parent_id are optional on this implementation
-- This is not guaranteed to happen in future versions and won't be considered a breaking change
local b3_single_header = headers["b3"]
if not b3_single_header then
local tracestate_header = headers["tracestate"]
if tracestate_header then
b3_single_header = match(tracestate_header, "^b3=(.+)$")
end
end

-- * The "sampled" section activates sampling with both "1" and "d". This is to match the
-- behavior of the X-B3-Flags header
if b3_single_header and type(b3_single_header) == "string" then
if b3_single_header == "1" or b3_single_header == "d" then
should_sample = true
Expand Down Expand Up @@ -166,21 +151,18 @@ local function parse_zipkin_b3_headers(headers)
return trace_id, span_id, parent_id, should_sample
end

local function parse_w3c_trace_context_headers(headers)

local function parse_w3c_trace_context_headers(w3c_header)
-- allow testing to spy on this.
local warn = kong.log.warn

local version, trace_id, parent_id, trace_flags
local should_sample = false

local w3c_trace_context_header = headers["traceparent"]

-- no W3C trace context
if w3c_trace_context_header == nil or type(w3c_trace_context_header) ~= "string" then
if type(w3c_header) ~= "string" then
return nil, nil, nil, should_sample
end

version, trace_id, parent_id, trace_flags = match(w3c_trace_context_header, W3C_TRACECONTEXT_PATTERN)
local version, trace_id, parent_id, trace_flags = match(w3c_header, W3C_TRACECONTEXT_PATTERN)

-- values are not parsable hexidecimal and therefore invalid.
if version == nil or trace_id == nil or parent_id == nil or trace_flags == nil then
Expand Down Expand Up @@ -218,28 +200,130 @@ local function parse_w3c_trace_context_headers(headers)
parent_id = from_hex(parent_id)

return trace_id, parent_id, should_sample
end


-- This plugin understands several tracing header types:
-- * Zipkin B3 headers (X-B3-TraceId, X-B3-SpanId, X-B3-ParentId, X-B3-Sampled, X-B3-Flags)
-- * Zipkin B3 "single header" (a single header called "B3", composed of several fields)
-- * spec: https://github.com/openzipkin/b3-propagation/blob/master/RATIONALE.md#b3-single-header-format
-- * W3C "traceparent" header - also a composed field
-- * spec: https://www.w3.org/TR/trace-context/
--
-- The plugin expects request to be using *one* of these types. If several of them are
-- encountered on one request, only one kind will be transmitted further. The order is
--
-- B3-single > B3 > W3C
--
-- Exceptions:
--
-- * When both B3 and B3-single fields are present, the B3 fields will be "ammalgamated"
-- into the resulting B3-single field. If they present contradictory information (i.e.
-- different TraceIds) then B3-single will "win".
--
-- * The erroneous formatting on *any* header (even those overriden by B3 single) results
-- in rejection (ignoring) of all headers. This rejection is logged.
local function find_header_type(headers)
local b3_single_header = headers["b3"]
if not b3_single_header then
local tracestate_header = headers["tracestate"]
if tracestate_header then
b3_single_header = match(tracestate_header, "^b3=(.+)$")
end
end

if b3_single_header then
return "b3-single", b3_single_header
end

if headers["x-b3-sampled"]
or headers["x-b3-flags"]
or headers["x-b3-traceid"]
or headers["x-b3-spanid"]
or headers["x-b3-parentspanid"]
then
return "b3"
end

local w3c_header = headers["traceparent"]
if w3c_header then
return "w3c", w3c_header
end
end

local function parse_http_req_headers(headers)

local function parse(headers)
-- Check for B3 headers first
local trace_id, span_id, parent_id, should_sample = parse_zipkin_b3_headers(headers)
local header_type, composed_header = find_header_type(headers)
local trace_id, span_id, parent_id, should_sample

-- TODO: Offer the option to configure which headers to use. For now, W3C wins if it's present
-- Check for W3C headers
local w3c_trace_id, w3c_parent_id, w3c_should_sample = parse_w3c_trace_context_headers(headers)
if w3c_trace_id then
trace_id, span_id, parent_id, should_sample = w3c_trace_id, nil, w3c_parent_id, w3c_should_sample
if header_type == "b3" or header_type == "b3-single" then
trace_id, span_id, parent_id, should_sample = parse_zipkin_b3_headers(headers, composed_header)
elseif header_type == "w3c" then
trace_id, parent_id, should_sample = parse_w3c_trace_context_headers(composed_header)
end

if not trace_id then
return trace_id, span_id, parent_id, should_sample
return header_type, trace_id, span_id, parent_id, should_sample
end

local baggage = parse_jaeger_baggage_headers(headers)

return trace_id, span_id, parent_id, should_sample, baggage
return header_type, trace_id, span_id, parent_id, should_sample, baggage
end


local function set(conf_header_type, found_header_type, proxy_span)
local set_header = kong.service.request.set_header

if conf_header_type ~= "preserve" and
found_header_type ~= nil and
conf_header_type ~= found_header_type
then
kong.log.warn("Mismatched header types. conf: " .. conf_header_type .. ". found: " .. found_header_type)
end

if conf_header_type == "b3"
or found_header_type == nil
or found_header_type == "b3"
then
set_header("x-b3-traceid", to_hex(proxy_span.trace_id))
set_header("x-b3-spanid", to_hex(proxy_span.span_id))
if proxy_span.parent_id then
set_header("x-b3-parentspanid", to_hex(proxy_span.parent_id))
end
local Flags = kong.request.get_header("x-b3-flags") -- Get from request headers
if Flags then
set_header("x-b3-flags", Flags)
else
set_header("x-b3-sampled", proxy_span.should_sample and "1" or "0")
end
end

if conf_header_type == "b3-single" or found_header_type == "b3-single" then
set_header("b3", fmt("%s-%s-%s-%s",
to_hex(proxy_span.trace_id),
to_hex(proxy_span.span_id),
proxy_span.should_sample and "1" or "0",
to_hex(proxy_span.parent_id)))
end

if conf_header_type == "w3c" or found_header_type == "w3c" then
set_header("traceparent", fmt("00-%s-%s-%s",
to_hex(proxy_span.trace_id),
to_hex(proxy_span.span_id),
proxy_span.should_sample and "01" or "00"))
end

for key, value in proxy_span:each_baggage_item() do
-- XXX: https://github.com/opentracing/specification/issues/117
set_header("uberctx-"..key, ngx.escape_uri(value))
end
end


return parse_http_req_headers
return {
parse = parse,
set = set,
from_hex = from_hex,
}
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