Refactor the kpt `printer` package

[mozesl-nokia]

Refactor the kpt printer package

Present

There are currently 2 copies of the printer package pkg/printer.printer and pkg/lib/kptops.packagePrinter
with the difference that the latter uses klog to print.

kpt itself never uses packagePrinter, but Porch does. The two have drifted in output in the past.

Proposal

• Create a new, exported printer implementation that can handle both cases.
  • Discuss if a klog adapter should live in kpt or Porch.
• Instead of the current weird way of passing the opts to OptPrintf, have the opts as state inside the printer object.
• Things such as the package name, image/executable name (or function ID) should be printed with every log line.
  • We could include additional, client-defined metadata (key-value pairs) that could be passed to the printer. For example, request ID, user, etc. from Porch.

Example

Old

Package "wordpress/mysql":
[RUNNING] "ghcr.io/kptdev/krm-functions-catalog/set-labels:latest" on package "wordpress/mysql"
[PASS] "ghcr.io/kptdev/krm-functions-catalog/set-labels:latest" in 311ms
  [Results]:
    [info]: set 7 labels in total

Package "wordpress":
[RUNNING] "ghcr.io/kptdev/krm-functions-catalog/set-annotations:latest" on 2 resource(s) on package "wordpress"
[PASS] "ghcr.io/kptdev/krm-functions-catalog/set-annotations:latest" in 223ms
  [Results]:
    [info] metadata.annotations: set annotations: {"tier":"mysql"}
    [info] metadata.annotations: set annotations: {"tier":"mysql"}
    [info] spec.template.metadata.annotations: set annotations: {"tier":"mysql"}
[RUNNING] "ghcr.io/kptdev/krm-functions-catalog/set-labels:latest" on package "wordpress"
[PASS] "ghcr.io/kptdev/krm-functions-catalog/set-labels:latest" in 204ms
  [Results]:
    [info]: set 14 labels in total
[RUNNING] "ghcr.io/kptdev/krm-functions-catalog/kubeconform:latest" on package "wordpress"
[PASS] "ghcr.io/kptdev/krm-functions-catalog/kubeconform:latest" in 431ms

Successfully executed 4 function(s) in 2 package(s).

New in kpt CLI (conceptually)

[RUNNING] image="set-labels" tag="latest" package="wordpress/wordpress-mysql"
[PASS] image="set-labels" tag="latest" package="wordpress/wordpress-mysql" time="311ms"
  [Results]:
    [info]: set 7 labels in total

[RUNNING] image="set-annotations" tag="latest" package="wordpress" resourceCount=2
[PASS] image="set-annotations" tag="latest" package="wordpress" time="223ms"
  [Results]:
    [info] metadata.annotations: set annotations: {"tier":"mysql"}
    [info] metadata.annotations: set annotations: {"tier":"mysql"}
    [info] spec.template.metadata.annotations: set annotations: {"tier":"mysql"}
[RUNNING] image="set-labels" tag="latest" package="wordpress"
[PASS] image="set-labels" tag="latest" package="wordpress" time="204ms"
  [Results]:
    [info]: set 14 labels in total
[RUNNING] image="kubeconform" tag="latest" package="wordpress"
[PASS] image="kubeconform" tag="latest" package="wordpress" time="431ms"

Successfully executed 4 function(s) in 2 package(s).

New in Porch (conceptually)

I0806 10:34:XX.YYYYY       1 runner.go:ZZZ] [RUNNING] image="set-labels" tag="latest" package="deployments.wordpress.wordpress-mysql.packagevariant-1" requestID="12d800e0-0ebe-4e92-8fee-3f6f58b5b59a" user="system:serviceaccount:porch-system:porch-controller"
I0806 10:34:XX.YYYYY       1 runner.go:ZZZ] [PASS] image="set-labels" tag="latest" package="deployments.wordpress.wordpress-mysql.packagevariant-1" time="311ms" requestID="12d800e0-0ebe-4e92-8fee-3f6f58b5b59a" user="system:serviceaccount:porch-system:porch-controller"
I0806 10:34:XX.YYYYY       1 runner.go:ZZZ]   [Results]:
I0806 10:34:XX.YYYYY       1 runner.go:ZZZ]     [info]: set 7 labels in total
I0806 10:34:XX.YYYYY       1 runner.go:ZZZ] [RUNNING] image="set-annotations" tag="latest" package="deployments.wordpress.packagevariant-1" resourceCount=2 requestID="12d800e0-0ebe-4e92-8fee-3f6f58b5b59a" user="system:serviceaccount:porch-system:porch-controller"
I0806 10:34:XX.YYYYY       1 runner.go:ZZZ] [PASS] image="set-annotations" tag="latest" package="deployments.wordpress.packagevariant-1" time="223ms" requestID="12d800e0-0ebe-4e92-8fee-3f6f58b5b59a" user="system:serviceaccount:porch-system:porch-controller"
I0806 10:34:XX.YYYYY       1 runner.go:ZZZ]   [Results]:
I0806 10:34:XX.YYYYY       1 runner.go:ZZZ]     [info] metadata.annotations: set annotations: {"tier":"mysql"}
I0806 10:34:XX.YYYYY       1 runner.go:ZZZ]     [info] metadata.annotations: set annotations: {"tier":"mysql"}
I0806 10:34:XX.YYYYY       1 runner.go:ZZZ]     [info] spec.template.metadata.annotations: set annotations: {"tier":"mysql"}
I0806 10:34:XX.YYYYY       1 runner.go:ZZZ] [RUNNING] image="set-labels" tag="latest" package="deployments.wordpress.packagevariant-1" requestID="12d800e0-0ebe-4e92-8fee-3f6f58b5b59a" user="system:serviceaccount:porch-system:porch-controller"
I0806 10:34:XX.YYYYY       1 runner.go:ZZZ] [PASS] image="set-labels" tag="latest" package="deployments.wordpress.packagevariant-1" time="204ms" requestID="12d800e0-0ebe-4e92-8fee-3f6f58b5b59a" user="system:serviceaccount:porch-system:porch-controller"
I0806 10:34:XX.YYYYY       1 runner.go:ZZZ]   [Results]:
I0806 10:34:XX.YYYYY       1 runner.go:ZZZ]     [info]: set 14 labels in total
I0806 10:34:XX.YYYYY       1 runner.go:ZZZ] [RUNNING] image="kubeconform" tag="latest" package="deployments.wordpress.packagevariant-1" requestID="12d800e0-0ebe-4e92-8fee-3f6f58b5b59a" user="system:serviceaccount:porch-system:porch-controller"
I0806 10:34:XX.YYYYY       1 runner.go:ZZZ] [PASS] image="kubeconform" tag="latest" package="deployments.wordpress.packagevariant-1" time="431ms" requestID="12d800e0-0ebe-4e92-8fee-3f6f58b5b59a" user="system:serviceaccount:porch-system:porch-controller"
I0806 10:34:XX.YYYYY       1 render_executor.go:ZZZ] Successfully executed 4 function(s) in 2 package(s) time="1.17s" requestID="12d800e0-0ebe-4e92-8fee-3f6f58b5b59a" user="system:serviceaccount:porch-system:porch-controller"

[SurbhiAgarwal1]

Hi @mozesl-nokia, I would like to work on this refactoring. Here is my proposed design and implementation plan:

Proposed Solution: Unified Stateful Printer Package

1. Problem Overview

Currently, pkg/printer (used by the kpt CLI) and pkg/lib/kptops.packagePrinter (used by Porch via klog) duplicate printing logic. Passing ad-hoc Options structs into OptPrintf leads to output drifting over time and lacks a clean way to attach structured contextual metadata (image, tag, package, requestID, user, time).

This proposal consolidates both implementations into a single, stateful, context-aware Printer interface under pkg/printer.

---

2. Architecture & Design

A. Stateful Printer Interface (pkg/printer/printer.go)

Instead of passing Options down call stacks, the printer maintains stateful key-value attributes and produces scoped sub-printers:

package printer

import (
	"io"
	"time"
)

// ContextualFields holds key-value metadata pairs (e.g. image, tag, package, requestID, user)
type ContextualFields map[string]string

type Printer interface {
	// Contextual scoping
	WithField(key, value string) Printer
	WithFields(fields ContextualFields) Printer
	WithPackage(pkgName string) Printer
	WithFunction(image, tag string) Printer

	// Lifecycle events for function execution
	PrintRunning(fnRef string, resourceCount int)
	PrintPass(fnRef string, duration time.Duration)
	PrintFail(fnRef string, duration time.Duration, err error)
	PrintResult(severity, msg string, targetRef string)
	PrintSummary(executedFnCnt, pkgCnt int, totalTime time.Duration)

	// Stream accessors
	OutStream() io.Writer
	ErrStream() io.Writer
}