Around Go: command line · 3 MIN READ

Pipelines, exit codes and explicit failure handling

Read pipeline failure behavior and keep configuration and secrets out of command strings.

A script is another program with success and failure paths. A command printing plausible output can still fail. Pipelines complicate this because the last command can succeed even when an earlier producer failed.

Observe the whole pipeline

Bash pipefail makes a pipeline fail when a component fails, instead of using only the final command's status. Check that status explicitly at the workflow boundary. set -e has exceptions in conditionals and other constructs, so it is not a replacement for understanding control flow.

bash

#!/usr/bin/env bash
set -u -o pipefail
if go test ./... | tee test.log; then
    printf "%s\n" "Tests passed"
else
    printf "%s\n" "Tests failed; inspect test.log" >&2
    exit 1
fi

Read the code

tee preserves a log while showing output. With pipefail, a failing go test makes the condition fail even when tee succeeds. This script is for a trusted local project and writes one named log file.

Pass configuration and inspect one setting

A prefix assignment belongs to one child process; export passes a variable to later children from this shell. Check selected non-secret settings instead of dumping the full environment. Already-running services keep their original environment.

bash

APP_ENV=development go run ./cmd/api
export APP_ENV=development
printf "APP_ENV=%s\n" "$APP_ENV"
command -v go

Read the code

The first line runs a foreground API until you stop it; execute the following commands after it exits or in another shell. The example assumes cmd/api exists and does not require a credential. command -v shows which Go executable Bash will resolve.

Make cleanup and retries deliberate

A trap can arrange cleanup of resources a script created, but it cannot roll back an external side effect automatically. Avoid rerunning a deployment simply because its status command timed out. Keep a stable operation identifier and inspect the outcome before retrying. As a script grows, move complex state transitions into a program with tests.

TAKE THIS WITH YOU

A successful last pipeline command does not prove upstream success. Preserve exit status, handle failure explicitly, and avoid exposing configuration secrets.

Check your understanding

Which statement is correct about bash pipefail?

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