Examples.

The guides use ./server to stand for your own app. To try a guide before you have instrumented anything, use shop: a small Go program in demo/workloads/shop that places four orders across four in-process services (web, checkout, inventory, payments). It exports OTLP traces and writes JSON logs tagged with trace and span IDs. It is the same app the recordings in the guides are made from.

Two of its orders are there to be found:

Set up

From the repository root, with Go installed:

go install ./cmd/praytel
(cd demo/workloads/shop && go install .)

Both binaries land in $(go env GOPATH)/bin. shop also runs without praytel, exporting nothing, so you can compare the two.

There is one example per release, in release order. Each uses only what that release and the ones before it provide.

1. Traces and logs

Traces

praytel --tui -- shop

Four traces fill in, one per order, each rooted at Orders.Create. Type gift to narrow to the order that failed, and follow the × marks down to Gateway.Bank.Authorize. Esc clears the search; Ctrl-C quits.

Guide: View traces from a running app.

Logs

First see what the app prints on its own, then the same lines joined:

shop -pace 50ms | head -4
praytel -- shop -pace 50ms

In the joined stream each line gains the name of the span that emitted it:

stdout Gateway.Bank.Authorize 4a2aac9c... 18e4b9ff... {"level":"ERROR","msg":"authorization refused", ...}

shop: taking orders carries no IDs, so it is reported as an orphan. Under praytel --tui -- shop, press Tab and type refused to search log bodies.

Guide: View logs correlated to traces.

2. Overview

praytel --tui -- shop

Press Ctrl-G. There is one box per span name, labelled with its service: web.Orders.Create calls checkout.Orders.Place, which fans out to inventory.Stock.Reserve, payments.Gateway.Charge and checkout.Orders.Repo.Save. Compare it with the calls in main.go. The arrow into checkout.Orders.Repo.Save reads ×3, not ×4: one order never saved. Type gift and the graph shrinks to what that order touched, with inventory.Stock.Release in place of the save.

Guide: Get an overview of a system.