Multi Span Traces

TLDR: Prefer to read code? See the GitLab sample pipeline for a working example.

tracepusher v0.5.0 and above supports tracing any arbitrarily complex multi-span trace. It does so by allowing users to generate and pass in their own trace-id and span-id.

Consider the following batch script:

#!/bin/bash

main_time_start=0

counter=1
limit=5

while [ $counter -le $limit ]
do
  echo "in a loop. interation ${counter}" # 1, 2, 3, 4, 5
done

main_time_end=$SECONDS
duration=$(( main_time_end - main_time_start ))

As a trace, this would be represented as 1 parent span (that lasts for 5 seconds). "Inside" that parent span would be 5 sub spans, each denoting "once around the loop".

In the default mode, tracepusher will auto-generate trace and span IDs but you can generate your own and pass them in. For example:

# trace_id is 32 digits
# span_id is 16
trace_id=$(openssl rand -hex 16)
span_id=$(openssl rand -hex 8)

The parent span would look like the following. Notice the --time-shift=true parameter is set. If this was not set, the timings would not make sense.

For more information, see time shifting

Parent Span Example

python3 tracepusher.py \
    --endpoint http://localhost:4318 \
    --service-name "serviceA" \
    --span-name "main_span" \
    --duration ${duration} \
    --trace-id ${trace_id} \
    --span-id ${span_id} \
    --time-shift True

Sub Span Example

# Note: subspan time is tracked independently to "main" span time
while [ $counter -lt $limit ]
do
  # Calculate unique ID for this span
  sub_span_id=$(openssl rand -hex 8)
  sub_span_time_start=$SECONDS

  # Do real work here...
  sleep 1

  subspan_time_end=$SECONDS
  duration=$$(( $time_end - $time_start ))
  counter=$(( $counter + 1 ))

  python3 tracepusher.py \
    --endpoint http://localhost:4318 \
    --service-name serviceA \
    --span-name "subspan${counter}" \
    --duration ${duration} \
    --trace-id ${trace_id} \
    --parent-span-id ${span_id} \
    --span-id ${subspan_id} \
    --time-shift True
done