mod_trace

Introduction

mod_trace enables tracing for requests based on defined rules.

Module Configuration

Description

conf/mod_trace/mod_trace.conf

Basic Configuration

Config Item	Description
Basic.DataPath	String Path of rule configuration
Basic.ServiceName	String Service name
Basic.TraceAgent	String Which trace agent to use (jaeger/zipkin)
Log.OpenDebug	Boolean Debug flag of module

Configuration about Zipkin

Config Item	Description
Zipkin.HTTPEndpoint	String Http endpoint to report traces to
Zipkin.SameSpan	String Whether to use Zipkin SameSpan RPC style traces
Zipkin.ID128Bit	String Whether to use 128 bit root span IDs
Zipkin.SampleRate	Float The rate between 0.0001 and 1.0 of requests to trace

Configuration about Jaeger

Config Item	Description
Jaeger.SamplingServerURL	String The address of jaeger-agent's HTTP sampling server
Jaeger.SamplingType	String The type of the sampler: const, probabilistic, rateLimiting, or remote
Jaeger.SamplingParam	Float Param passed to the sampler
Jaeger.LocalAgentHostPort	String The address of jaeger-agent which receives spans
Jaeger.Propagation	String Which propagation format to use (jaeger/b3)
Jaeger.Gen128Bit	Boolean Whether to use 128 bit root span IDs
Jaeger.TraceContextHeaderName	String The http header name used to propagate tracing context
Jaeger.CollectorEndpoint	String The address of jaeger-collector
Jaeger.CollectorUser	String Basic http authentication when sending spans to jaeger-collector
Jaeger.CollectorPassword	String Basic http authentication when sending spans to jaeger-collector

Configuration about Elastic

Config Item	Description
Elastic.ServerURL	String Set the URL of the Elastic APM server
Elastic.SecretToken	String Set the token used to connect to Elastic APM Server

Example

Example for Zipkin

[Basic]
DataPath = mod_trace/trace_rule.data
ServiceName = bfe

# Which trace agent to use (zipkin, jaeger, elastic)
TraceAgent = zipkin

[Log]
OpenDebug = false

[Zipkin]
# Zipkin, only useful when the TraceAgent is zipkin

# HTTP Endpoint to report traces to
HTTPEndpoint = http://127.0.0.1:9411/api/v2/spans

# Use Zipkin SameSpan RPC style traces
SameSpan = false

# Use Zipkin 128 bit root span IDs
ID128Bit = true

# The rate between 0.0001 and 1.0 of requests to trace
SampleRate = 1.0

Example for Jaeger

[Basic]
DataPath = mod_trace/trace_rule.data
ServiceName = bfe

# Which trace agent to use (zipkin, jaeger, elastic)
TraceAgent = jaeger

[Log]
OpenDebug = false

[Jaeger]
# Jaeger, only useful when the TraceAgent is jaeger

# SamplingServerURL is the address of jaeger-agent's HTTP sampling server
SamplingServerURL = http://127.0.0.1:5778/sampling

# Type specifies the type of the sampler: const, probabilistic, rateLimiting, or remote
SamplingType = const

# Param is a value passed to the sampler.
# Valid values for Param field are:
# - for "const" sampler, 0 or 1 for always false/true respectively
# - for "probabilistic" sampler, a probability between 0 and 1
# - for "rateLimiting" sampler, the number of spans per second
# - for "remote" sampler, param is the same as for "probabilistic"
#   and indicates the initial sampling rate before the actual one
#   is received from the mothership.
SamplingParam = 1.0

# LocalAgentHostPort instructs reporter to send spans to jaeger-agent at this address
LocalAgentHostPort = 127.0.0.1:6831

# Which propagation format to use (jaeger/b3)
Propagation = jaeger

# Use Jaeger 128 bit root span IDs
Gen128Bit = true

# TraceContextHeaderName is the http header name used to propagate tracing context.
TraceContextHeaderName = uber-trace-id

# Instructs reporter to send spans to jaeger-collector at this URL
CollectorEndpoint = ""

# CollectorUser for basic http authentication when sending spans to jaeger-collector
CollectorUser = ""

# CollectorPassword for basic http authentication when sending spans to jaeger-collector
CollectorPassword = ""

Example for Elastic

[Basic]
DataPath = mod_trace/trace_rule.data
ServiceName = bfe

# Which trace agent to use (zipkin, jaeger, elastic)
TraceAgent = elastic

[Log]
OpenDebug = false

[Elastic]
# Elastic, only useful when TraceAgent is elastic

# Set the URL of the Elastic APM server
ServerURL = http://127.0.0.1:8200

# Set the token used to connect to Elastic APM Server
SecretToken = ""

Rule Configuration

Description

conf/mod_trace/trace_rule.data

Config Item	Description
Version	String Version of the config file
Config	Object Trace rules for each product
Config[k]	String Product name
Config[v]	Object A list of trace rules
Config[v][]	Object A trace rule
Config[v][].Cond	String Condition expression, See Condition
Config[v][].Enable	Boolean Enable trace

Example

{
  "Version": "20200218210000",
  "Config": {
    "example_product": [
       {
         "Cond": "req_host_in(\"example.org\")",
         "Enable": true
       }
    ]
  }
}