feat(tracing): Add instana header support in propagation

changelog/unreleased/kong/instana-header-support.yml

@@ -0,0 +1,4 @@
+message: |
+    **OpenTelemetry**: include instana header support in propagation
+type: feature
+scope: Plugin

kong-3.9.0-0.rockspec

@@ -682,6 +682,7 @@ build = {
     ["kong.observability.tracing.propagation.extractors.gcp"] = "kong/observability/tracing/propagation/extractors/gcp.lua",
     ["kong.observability.tracing.propagation.extractors.aws"] = "kong/observability/tracing/propagation/extractors/aws.lua",
     ["kong.observability.tracing.propagation.extractors.datadog"] = "kong/observability/tracing/propagation/extractors/datadog.lua",
+    ["kong.observability.tracing.propagation.extractors.instana"] = "kong/observability/tracing/propagation/extractors/instana.lua",
     ["kong.observability.tracing.propagation.injectors._base"] = "kong/observability/tracing/propagation/injectors/_base.lua",
     ["kong.observability.tracing.propagation.injectors.w3c"] = "kong/observability/tracing/propagation/injectors/w3c.lua",
     ["kong.observability.tracing.propagation.injectors.b3"] = "kong/observability/tracing/propagation/injectors/b3.lua",
@@ -691,6 +692,7 @@ build = {
     ["kong.observability.tracing.propagation.injectors.gcp"] = "kong/observability/tracing/propagation/injectors/gcp.lua",
     ["kong.observability.tracing.propagation.injectors.aws"] = "kong/observability/tracing/propagation/injectors/aws.lua",
     ["kong.observability.tracing.propagation.injectors.datadog"] = "kong/observability/tracing/propagation/injectors/datadog.lua",
+    ["kong.observability.tracing.propagation.injectors.instana"] = "kong/observability/tracing/propagation/injectors/instana.lua",
     ["kong.observability.tracing.request_id"] = "kong/observability/tracing/request_id.lua",
     ["kong.observability.tracing.tracing_context"] = "kong/observability/tracing/tracing_context.lua",
 

kong/observability/tracing/propagation/extractors/instana.lua

@@ -0,0 +1,57 @@
+local _EXTRACTOR        = require "kong.observability.tracing.propagation.extractors._base"
+local propagation_utils = require "kong.observability.tracing.propagation.utils"
+local from_hex          = propagation_utils.from_hex
+
+local INSTANA_EXTRACTOR = _EXTRACTOR:new({
+  headers_validate = {
+    any = {
+      "x-instana-t",
+      "x-instana-s",
+      "x-instana-l",
+    }
+  }
+})
+
+function INSTANA_EXTRACTOR:get_context(headers)
+
+  local trace_id = headers["x-instana-t"]
+  local span_id = headers["x-instana-s"]
+  local level_id = headers["x-instana-l"] 
+
+  if trace_id then
+    trace_id = trace_id:match("^(%x+)")
+    if not trace_id then
+      kong.log.warn("x-instana-t header invalid; ignoring.")
+    end
+  end
+
+  if span_id then
+    span_id = span_id:match("^(%x+)")
+    if not span_id then
+      kong.log.warn("x-instana-s header invalid; ignoring.")
+    end
+  end
+
+  if level_id then
+    -- the flag can come in as "0" or "1" 
+    -- or something like the following format
+    -- "1,correlationType=web;correlationId=1234567890abcdef"
+    -- here we only care about the first value
+    level_id = level_id:match("^([0-1])$") 
+              or level_id:match("^([0-1]),correlationType=(.-);correlationId=(.*)")
+  end
+  local should_sample = level_id or "1"
+
+
+
+  trace_id = from_hex(trace_id) or nil
+  span_id = from_hex(span_id) or nil
+
+  return {
+    trace_id      = trace_id,
+    span_id       = span_id,
+    should_sample = should_sample,
+  }
+end
+
+return INSTANA_EXTRACTOR

kong/observability/tracing/propagation/init.lua

@@ -47,7 +47,7 @@ local function get_plugin_params(config)
         formats.DATADOG,
         formats.AWS,
         formats.GCP,
-
+        formats.INSTANA
       }
       propagation_config.inject = { "preserve" }
 
@@ -63,6 +63,7 @@ local function get_plugin_params(config)
         formats.DATADOG,
         formats.AWS,
         formats.GCP,
+        formats.INSTANA,
       }
       propagation_config.inject = {
         -- the old logic used to propagate the "found" incoming format

kong/observability/tracing/propagation/injectors/instana.lua

@@ -0,0 +1,31 @@
+local _INJECTOR = require "kong.observability.tracing.propagation.injectors._base"
+local to_hex    = require "resty.string".to_hex
+
+local INSTANA_INJECTOR = _INJECTOR:new({
+  name = "instana",
+  context_validate = {}, -- all fields are optional
+  trace_id_allowed_sizes = { 16 },
+  span_id_size_bytes = 16,
+})
+
+
+function INSTANA_INJECTOR:create_headers(out_tracing_ctx)
+  local headers = {
+    ["x-instana-t"] = to_hex(out_tracing_ctx.trace_id) or nil, 
+    ["x-instana-s"] = to_hex(out_tracing_ctx.span_id) or nil,
+  }
+
+  if out_tracing_ctx.should_sample ~= nil then
+    headers["x-instana-l"] = out_tracing_ctx.should_sample and "1" or "0"
+  end
+
+  return headers
+end
+
+
+function INSTANA_INJECTOR:get_formatted_trace_id(trace_id)
+  return { instana = to_hex(trace_id) }
+end
+
+
+return INSTANA_INJECTOR

kong/observability/tracing/propagation/utils.lua

@@ -18,6 +18,7 @@ local FORMATS = {
   DATADOG   = "datadog",
   AWS       = "aws",
   GCP       = "gcp",
+  INSTANA   = "instana",
 }
 
 local function hex_to_char(c)

kong/plugins/opentelemetry/schema.lua

@@ -78,7 +78,7 @@ return {
                 old_default = "preserve" },
               required = false,
               default = "preserve",
-              one_of = { "preserve", "ignore", "b3", "b3-single", "w3c", "jaeger", "ot", "aws", "gcp", "datadog" } } },
+              one_of = { "preserve", "ignore", "b3", "b3-single", "w3c", "jaeger", "ot", "aws", "gcp", "datadog", "instana" } } },
         { sampling_rate = {
           description = "Tracing sampling rate for configuring the probability-based sampler. When set, this value supersedes the global `tracing_sampling_rate` setting from kong.conf.",
           type = "number",