feat: agent metadata with custom collectors

internal/agent/metadata/collector/buildinfo/collector.go

@@ -0,0 +1,31 @@
+package buildinfo
+
+import (
+	"context"
+	"runtime/debug"
+
+	"forge.cadoles.com/Cadoles/emissary/internal/agent/metadata"
+	"github.com/pkg/errors"
+)
+
+const (
+	MetadataBuildInfo = "buildinfo"
+)
+
+type Collector struct{}
+
+// Collect implements agent.MetadataCollector
+func (c *Collector) Collect(ctx context.Context) (string, string, error) {
+	buildInfo, ok := debug.ReadBuildInfo()
+	if !ok {
+		return "", "", errors.WithStack(metadata.ErrMetadataNotAvailable)
+	}
+
+	return MetadataBuildInfo, buildInfo.String(), nil
+}
+
+func NewCollector() *Collector {
+	return &Collector{}
+}
+
+var _ metadata.Collector = &Collector{}