compression

pkg/compression

Tiny zstd + base64 compression helper used for the HAProxyCfg / HAProxyMapFile / HAProxyGeneralFile / HAProxyCRTListFile CRD payloads.

Overview

Two functions, no state to construct, no goroutines. The package wraps a process-global zstd.Encoder (level SpeedDefault) and zstd.Decoder lazily so callers don't pay the construction cost more than once.

The encoder/decoder are global because compression is always sequential in the controller's hot path — every call holds the encoder for the duration. If concurrent compression ever becomes desirable, switch to a sync.Pool.

API

func Compress(data string) string             // → zstd-compressed bytes, base64-encoded (cannot fail)
func Decompress(data string) (string, error)  // ← base64 → zstd → original string

Decompress(Compress(s)) round-trips. The base64 wrapper is there because the compressed payload lives inside Kubernetes CRD string fields, which can't carry raw binary.

When to Compress

pkg/k8s/configpublisher.PublishConfig switches to compression when the payload exceeds controller.configPublishing.compressionThreshold (default 1 MiB). The CRD then carries spec.compressed: true and consumers know to call Decompress on spec.content.

# Operator-side decompression (using the CLI):
kubectl get haproxycfg <name> -o jsonpath='{.spec.content}' | base64 -d | zstd -d

See Also

• pkg/k8s/configpublisher — primary caller; threshold-driven compression
• docs/site/docs/crd-reference.md — operator-facing description of the compression knob

License

Apache-2.0 — see root LICENSE.