This example adds configuration inspection and a custom greet command to a small application. It uses local fixtures and in-memory defaults, with no external services. See module selection for dependencies and Go requirements. Use Go 1.27.0 on PATH for this checkout.

From the repository root:

cd integrations/ckconfig/examples/simple
export GOWORK=off GOTOOLCHAIN=local
go run . config show

The output includes the default greeting, Hello, and schema version 2. This example can run against its declared released dependencies with the workspace disabled.

Inspect and override a value

# Discover configuration paths under schema.
go run . config explain --list --under /schema
# Change the greeting for this invocation and show just that value.
go run . config show --path /greeting --set '/greeting="Hi"'

The second command prints Hi. It does not edit a file.

Compare configurations

go run . config diff --config fixtures/before.yml --against-config fixtures/after.yml

The report includes changes.greeting: Goodbye.

# Expected status 3: the overridden greeting differs from the ordinary default.
go run . config diff --set '/greeting="Hi"' --details --check

This compares the overridden left side with ordinary configuration on the right. go run prints exit status 3 and itself exits with status 1; a built executable returns the application's status 3 directly.

Inspect warnings and failed loads

# Schema version 1 produces a warning, visible in verbose mode.
go run . config show --config fixtures/before.yml --verbose
# Quiet mode hides the configuration report and warning.
go run . config show --config fixtures/before.yml --quiet

Ordinary mode hides the warning but still displays configuration.

# Intentional failure: show detailed validation findings for the invalid fixture.
go run . config validate --config fixtures/invalid.yml --details --severity error
# Intentional failure: still show the source recorded before loading failed.
go run . config sources --config fixtures/invalid.yml --source-id source-1

Both commands retain the load failure. source-1 belongs to this fixture's load; other configurations can have different source IDs. See the CLI reference for report and status rules.

Try a custom command

go run . greet
go run . greet --count=0 --tag=first --tag second

The handler reports its greeting, count, and tags. It distinguishes an omitted count from an explicitly supplied zero and preserves repeated tag order.

How it is wired

One ConfigKit scope supplies the standard config commands. Without --config, its loader uses an in-memory default. Supplied configuration and overlay values are passed to ConfigKit unchanged. The scope enables temporary overrides and passes them into its ordinary ConfigKit load. The consumer guide explains loader and scope setup.

Run GOWORK=off GOTOOLCHAIN=local go test ./... from this example directory to check it against its declared dependencies.