currentconfigstore

pkg/controller/currentconfigstore

In-memory cache of the parsed HAProxy currentConfig exposed to templates.

Overview

Templates can reference the previously-deployed HAProxy configuration to keep server-slot ordering stable across rolling deploys (so connections don't migrate when an unrelated backend changes). This package provides the cache that holds that pre-parsed config: the HAProxyCfg CRD watcher feeds it raw resource bytes, and the renderer reads back a *parserconfig.StructuredConfig that templates consume via the currentConfig runtime variable.

This is a utility component — direct calls, no event loop, no goroutine. It's safe for concurrent reads and serialised writes via an internal sync.RWMutex.

Quick Start

import "gitlab.com/haproxy-haptic/haptic/pkg/controller/currentconfigstore"

store, err := currentconfigstore.New(logger)
if err != nil { /* parser construction failed */ }

// Watcher's OnChange callback feeds the raw resource (or nil on delete)
store.Update(unstructuredHAProxyCfg)

// Renderer pulls the parsed value
cfg := store.Get() // *parserconfig.StructuredConfig (nil if not yet populated)

Hot-Path Optimisations

Update is called every time the HAProxyCfg CRD changes, including no-op status updates. Two short-circuits keep the parsing cost bounded:

1. Generation check — if metadata.generation matches the last-seen value, the spec hasn't changed and the cached config is returned without re-parsing.
2. Content hash — if the generation moved, a spec.checksum field (set by the config-publisher) is compared against the cached hash; if it matches, parsing is skipped without even decompressing. If no spec.checksum is present the content is decompressed and SHA-256'd, and parsing is skipped if the hash matches.

A single *parser.Parser is reused across calls to avoid the per-call parser.New() overhead.

See Also

• pkg/dataplane/parser — the client-native wrapper that produces *StructuredConfig
• pkg/controller/renderer — the consumer that exposes Get() to templates as currentConfig
• pkg/compression — handles the optional zstd+base64-encoded payload of large HAProxyCfg resources (above controller.configPublishing.compressionThreshold, default 1 MiB)

License

Apache-2.0 — see root LICENSE.