Documentation
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Overview ¶
Package shield reconciles elchi-shield's watched config directory on the edge host to a control-plane-supplied desired state. elchi-shield self-watches that directory (fsnotify + debounce + atomic hot-reload + last-good), so the agent only lands files atomically — it never signals shield to reload.
Sync is two-phase to keep shield's view consistent. PREPARE validates every file and stages it into a sibling temp file (".tmp", which shield's loader ignores by extension) — slow work like downloads happens here, touching no live file, so any error aborts with the directory unchanged. COMMIT then renames the staged temps into place in a fast burst that shield's debounce coalesces into a single reload of the final state.
Index ¶
Constants ¶
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Variables ¶
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Functions ¶
func ConfirmReload ¶ added in v1.3.0
func ConfirmReload(ctx context.Context, before ShieldState, log *logger.Logger) (appliedVersion string, reloadOk bool)
ConfirmReload polls shield after a push and reports the truthful active version + whether the new config actually loaded. It returns ok=true when shield's version advances (new config live) or when nothing changed because the pushed content was identical to what's already loaded; ok=false when shield's reload-failure counter advances (rejected → kept last-good) or shield's state cannot be confirmed.
func ListConfig ¶
func ListConfig(_ *logger.Logger) ([]*client.ShieldFile, error)
ListConfig returns the files currently under shield's config dir (path relative to the root, sha256, octal mode); content is omitted. A missing dir yields an empty list (not an error).
func SyncConfig ¶
SyncConfig reconciles shield's watched config directory (models.ShieldConfigPath) to match cfg. See the package doc for the two-phase model. On full_sync it also removes any managed file not in the set (deletions propagate). On a prepare-phase error the directory is left unchanged; a commit-phase error (rare — only a catastrophic rename failure) may leave earlier files applied, with the rest rolled back, and is reported. The returned changed flag reports whether anything on disk actually changed (a file committed or pruned) — false means the bundle was already fully applied, so shield has nothing to reload and the caller can skip the reload confirmation wait entirely (idempotent re-pushes, e.g. on client reconnect, would otherwise burn the full confirmation timeout per push).
Types ¶
type ShieldState ¶ added in v1.3.0
ShieldState is a snapshot of shield's active-config view captured before a push, so ConfirmReload can distinguish "loaded the new config" (version changed) from "rejected, kept last-good" (failure counter advanced).
func SnapshotState ¶ added in v1.3.0
func SnapshotState(ctx context.Context) ShieldState
SnapshotState reads shield's current active version + reload-failure counter. Best-effort: an unreachable shield yields a zero-value (Reachable=false) state, which ConfirmReload still handles.
Source Files