Module opentracing¶

set_global_tracer (tracer)¶

Set global tracer

Parameters:

• tracer: (table)

get_global_tracer ()¶

Get global tracer

Returns:

(table) tracer

start_span (name, opts)¶

Start root span

Parameters:

• name: (string)
• opts: table specifying modifications to make to thenewly created span. The following parameters are supported: trace_id , references ,a list of referenced spans; start_time , the time to mark when the spanbegins (in microseconds since epoch); tags , a table of tags to add tothe created span.
  • trace_id: (optional string)
  • child_of: (optional table)
  • references: (optional table)
  • tags: (optional table)

Returns:

(table) span

start_span_from_context (context, name)¶

Start new child span from context

Parameters:

• context: (table)
• name: (string)

Returns:

(table) span

trace_with_context (name, ctx, fun, …)¶

Trace function with context by global tracer This function starts span from global tracer and finishes it after execution

Parameters:

• name: (string) span name
• ctx: (table) context
• fun: (function) wrapped function
• …: (vararg) function’s arguments

Returns:

(vararg) result

Or

(nil) nil

(string) err error message

Usage:¶

-- Process HTTP request
local ctx = opentracing.extractors.http(req.headers)
local result, err = opentracing.trace_with_context('process_data', ctx, process_data, req.body)
-- Wrap functions. In example we create root span that generates two child spans
local span = opentracing.start_span()
local result, err = opentracing.trace_with_context('format_string', span:context(), format, str)
if not result ~= nil then
    print('Error: ', err)
end
opentracing.trace_with_context('print_string', span:context(), print, result)
span:finish()

trace (name, fun, …)¶

Trace function by global tracer This function starts span from global tracer and finishes it after execution

Parameters:

• name: (string) span name
• fun: (function) wrapped function
• …: (vararg) function’s arguments

Returns:

(vararg) result

Or

(nil) nil

(string) err error message

Usage:¶

local result, err = opentracing.trace_with_context('process_data', process_data, req.body)