mesh-sdk/go/compose/render.go

package compose

import (
	"fmt"
	"sort"
	"strings"

	"git.novox.be/novox/mesh-sdk/go/catalogue"
)

// Rendered is everything a node's declaration is composed with (plan.go renderingFor), over an Input: the place half (Places)
// and the credential half. Nothing was allocated, made, kept or written; what a send would do is returned for the caller to do.
type Rendered struct {
	Rendering catalogue.Rendering
	// ForeseenPorts are the ports the mesh may assign that the Input holds none for ("<module>:<port>").
	ForeseenPorts []string
	// Foreseen are the stand-ins the composition used for what the Input does not hold: an own secret the next send makes
	// ("<module>/<name>"), a grant's sealed copy, the certificate and the bus's user list.
	Foreseen []string
	// CoreBoxesWanted are the core credentials whose box the send must ask the vault for and keep.
	CoreBoxesWanted []CoreBoxWanted
	// Withheld are the consumers the grants leave out because their identity overflows the provision's bound (novox/hq ADR 0225),
	// and Unbound those whose credential from this node is on record and whose own resolution binds them elsewhere (issue
	// 274). The controller says them; a check refuses a change that adds one (ADR 0446 clause 1).
	Withheld []catalogue.Overflow
	Unbound  []catalogue.Unbound
	// Said are the lines the controller says while composing (the bus users left out for want of a credential).
	Said []string
}

// Render composes the rendering of a node: the grants it must create, where it puts its ports, its own secrets, the vault's boxes,
// its certificate, the names of the mesh, the bus's user list and its membership. The refusals are the controller's, in its words;
// where more than one fault stands, the first reported may differ from the controller's, which interleaves the halves.
func Render(in Input, node string, mode Mode) (Rendered, error) {
	return newComposer(in).render(node, mode)
}

func (c *composer) render(nodeName string, mode Mode) (Rendered, error) {
	resolved, err := c.planFor(nodeName)
	if err != nil {
		return Rendered{}, err
	}
	node, err := c.in.node(nodeName)
	if err != nil {
		return Rendered{}, err
	}
	plan := resolved.Plan
	var out Rendered
	foreseen := func(s string) { out.Foreseen = append(out.Foreseen, s) }

	grants, withheld, unbound, grantsForeseen, err := c.grantsFor(nodeName)
	if err != nil {
		return Rendered{}, err
	}
	placed, err := c.places(nodeName, resolved)
	if err != nil {
		return Rendered{}, err
	}
	r := placed.Rendering
	out.ForeseenPorts = placed.ForeseenPorts
	r.Grants, r.Withheld, r.Unbound = grants, withheld, unbound
	out.Withheld, out.Unbound = withheld, unbound
	for _, g := range grantsForeseen {
		foreseen(g)
	}

	// And each module's own secrets: a module handed to the provisioner has its secrets from the vault through the client.
	handing := catalogue.Rendering{Hands: r.Hands, Provisioner: r.Provisioner}
	needed, foreseenOwn, err := c.ownSecretsFor(node, plan, handing, mode)
	if err != nil {
		return Rendered{}, err
	}
	r.Needed = needed
	if mode == Foreseeing || len(foreseenOwn) > 0 {
		r.Foreseen = foreseenOwn
	}
	var names []string
	for module, secrets := range foreseenOwn {
		for name := range secrets {
			names = append(names, module+"/"+name)
		}
	}
	sort.Strings(names)
	for _, n := range names {
		foreseen(n)
	}

	// The core's own credentials as the vault sealed them, for an engine that opens the vault's box.
	if node.Stated && node.Contract >= VaultBoxContract {
		sealed, notPlaced, wanted := c.coreBoxesFor(node, plan.Modules, handing)
		r.VaultSealed, r.NotPlaced = sealed, notPlaced
		out.CoreBoxesWanted = wanted
	}

	// And a certificate for this machine's name inside the mesh, when anything on it asks.
	for _, m := range plan.Modules {
		if m.Certificate == nil {
			continue
		}
		certificate, authority, stood, err := c.certificateFor(node)
		if err != nil {
			return Rendered{}, err
		}
		r.Certificate, r.Authority = certificate, authority
		if stood {
			foreseen("the certificate and the authority of " + nodeName)
		}
		break
	}

	// The bus's user list, for the machine that runs the bus: names and hashes the Input carries, never passwords.
	if holdsTheBus(plan.Modules) {
		r.BusUsers = c.in.BusUsers
		if r.BusUsers == "" {
			r.BusUsers = ForeseenBusUsers
			foreseen("the bus's user list")
		}
		if len(c.in.BusMissing) > 0 {
			out.Said = append(out.Said, fmt.Sprintf("the bus's user list leaves out %d user(s) the mesh has minted no credential "+
				"for: %s. Each is a user that cannot connect until one is issued", len(c.in.BusMissing), strings.Join(c.in.BusMissing, ", ")))
		}
	}
	r.BusMembership = c.in.BusMemberships[nodeName]
	out.Rendering = r
	return out, nil
}