Survey the machine, and say what an install would do to it

The first two pieces of the installer, and deliberately the two that change
nothing: what this machine is, and what would happen to it.

The survey is the floor under every later choice -- a component can only
offer a container shape if Docker answers for this user, or a host shape on
a systemd machine with what that shape needs. It reports what it could not
establish as unknown rather than guessing: an unprivileged probe of port 25
means "I may not bind this", not "something is listening", and reporting
the first as the second is a lie an operator would act on.

The plan is one list, and it will have three readers: --dry-run prints it,
the interface will show it before anything happens, and apply will walk it.
What you are shown is what runs.

Tested on a fresh Debian 13 in qemu, which has neither Docker nor Node and
so exercises every unavailable shape: 23 checks, including that nothing was
created by any of it. The lab that machine runs in is in e2e/vm.
This commit is contained in:
2026-09-22 17:56:20 -07:00
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// SPDX-FileCopyrightText: 2026 Coffey Labs
// SPDX-License-Identifier: AGPL-3.0-or-later
// Package plan turns what the operator chose, and what the machine is, into
// the list of things that would happen -- before any of them do.
//
// Everything the installer does goes through a plan. The interface shows it
// on its fifth screen, `--dry-run` prints it and stops, and apply walks it.
// One list, three readers: what you are shown is what runs.
package plan
import (
"fmt"
"strings"
"git.coffeylabs.org/inbuxa/inbuxa-installer/internal/host"
)
// Component is one of the three programs.
type Component string
const (
Server Component = "server"
Console Component = "console"
Webmail Component = "webmail"
)
// Shape is how a component is installed here.
type Shape string
const (
Skip Shape = "skip"
Container Shape = "container"
Host Shape = "host"
)
// Names as they are shown to a person. The programs have names; the
// components have jobs.
var names = map[Component]string{
Server: "inbuxa-server (the mail server)",
Console: "inbuxa Admin (the console)",
Webmail: "inbuxa webmail",
}
// Choice is one row of the matrix.
type Choice struct {
Component Component
Shape Shape
}
// Options is everything the six screens collect.
type Options struct {
Domain string
MailHost string
ConsoleHost string
WebmailHost string
ACMEEmail string
Local bool // loopback evaluation: no public ports, no certificates
Dir string
Proxy string // "caddy", "snippets", "none"
Choices []Choice
}
// Shape returns what was chosen for a component.
func (o Options) Shape(c Component) Shape {
for _, ch := range o.Choices {
if ch.Component == c {
return ch.Shape
}
}
return Skip
}
// Defaults fills in the names that follow from the domain, leaving anything
// the operator set alone.
func (o *Options) Defaults() {
if o.Domain == "" {
return
}
if o.MailHost == "" {
o.MailHost = "mail." + o.Domain
}
if o.ConsoleHost == "" {
o.ConsoleHost = "admin." + o.Domain
}
if o.WebmailHost == "" {
o.WebmailHost = "webmail." + o.Domain
}
if o.ACMEEmail == "" {
o.ACMEEmail = "postmaster@" + o.Domain
}
if o.Dir == "" {
o.Dir = "/var/lib/inbuxa"
}
if o.Proxy == "" {
o.Proxy = "caddy"
}
}
// Availability says whether a shape can be chosen for a component on this
// machine, and why not when it cannot. The interface dims what it cannot
// offer and shows the reason beside it; a flag that asks for it anyway gets
// the same sentence as an error.
type Availability struct {
OK bool
Why string
}
// Available answers for one cell of the matrix.
func Available(f host.Facts, c Component, s Shape) Availability {
switch s {
case Skip:
return Availability{OK: true}
case Container:
if !f.Docker.Present {
return Availability{Why: "docker is not installed"}
}
if !f.Docker.Usable {
return Availability{Why: f.Docker.Why}
}
return Availability{OK: true}
case Host:
if !f.Systemd {
return Availability{Why: "a host install needs systemd, which is not running this machine"}
}
switch c {
case Server:
return Availability{OK: true}
case Console:
return Availability{OK: true}
case Webmail:
if !f.Node.Present {
return Availability{Why: "a host install of the webmail needs Node 22 or newer; none is installed"}
}
if f.Node.Major < 22 {
return Availability{Why: fmt.Sprintf("a host install of the webmail needs Node 22 or newer; found %s", f.Node.Version)}
}
return Availability{OK: true}
}
}
return Availability{Why: "unknown shape"}
}
// Step is one thing the installer will do, in the order it will do it.
type Step struct {
Title string // shown as a line in the plan and ticked off during apply
Detail []string // the files, units, containers and ports it touches
}
// Plan is the whole of it.
type Plan struct {
Options Options
Steps []Step
Ports []int // what will be bound, once, across every component
DNS []string // records the domain needs for this shape
Warnings []string // things that are not refusals but should be read
}
// Build works out what would happen. It does not touch the machine: every
// fact it needs is in the survey it was given.
func Build(f host.Facts, o Options) (Plan, error) {
o.Defaults()
p := Plan{Options: o}
if o.Domain == "" && !o.Local {
return p, fmt.Errorf("a domain is needed (or --local for a loopback evaluation)")
}
chosen := 0
for _, c := range []Component{Server, Console, Webmail} {
s := o.Shape(c)
if s == Skip {
continue
}
chosen++
if a := Available(f, c, s); !a.OK {
return p, fmt.Errorf("%s as a %s install: %s", names[c], s, a.Why)
}
}
if chosen == 0 {
return p, fmt.Errorf("nothing chosen: pick at least one component")
}
if !f.Root {
p.Warnings = append(p.Warnings, "not running as root: installing units, users and files under /etc will fail")
}
if f.MemoryMB > 0 && f.MemoryMB < 2048 {
p.Warnings = append(p.Warnings, fmt.Sprintf("%d MB of memory: a mail server with a full text index wants 2 GB or more", f.MemoryMB))
}
if f.DiskFreeGB > 0 && f.DiskFreeGB < 10 {
p.Warnings = append(p.Warnings, fmt.Sprintf("%d GB free: mail, indexes and images need room to grow", f.DiskFreeGB))
}
if f.Existing != "" {
p.Warnings = append(p.Warnings, "an install is already recorded in "+f.Existing+": this run will converge it, not duplicate it")
}
p.Steps = append(p.Steps, Step{
Title: "Write the deployment directory",
Detail: []string{o.Dir + "/ (configuration, state and the credentials file)"},
})
if s := o.Shape(Server); s != Skip {
p.Ports = append(p.Ports, 25, 465, 993, 995, 4190)
switch s {
case Container:
p.Steps = append(p.Steps, Step{
Title: "Start the mail server as a container",
Detail: []string{
"image: registry.coffeylabs.org/inbuxa/inbuxa-server (pinned by digest)",
"volumes: inbuxa-data, inbuxa-etc",
"ports: 25, 465, 993, 995, 4190, and 8081 on loopback for the proxy",
},
})
case Host:
p.Steps = append(p.Steps, Step{
Title: "Install the mail server on this machine",
Detail: []string{
"binary: /usr/local/bin/inbuxa-server, from the release on git.coffeylabs.org",
"user: inbuxa (system, no login), data in " + o.Dir + "/server",
"unit: /etc/systemd/system/inbuxa-server.service",
},
})
}
p.Steps = append(p.Steps, Step{
Title: "First boot",
Detail: []string{
"bootstrap over JMAP, then set the front-end URLs, which registers both first-party OAuth clients",
"turn on ACME, trust the proxy, create the first account",
"write " + o.Dir + "/credentials and " + o.Dir + "/dns.zone",
},
})
}
if s := o.Shape(Console); s != Skip {
switch s {
case Container:
p.Steps = append(p.Steps, Step{
Title: "Start the console as a container",
Detail: []string{
"image: registry.coffeylabs.org/inbuxa/inbuxa-admin (pinned by digest)",
"port: 8082 on loopback, behind the proxy",
},
})
case Host:
p.Steps = append(p.Steps, Step{
Title: "Install the console on this machine",
Detail: []string{
"files: " + o.Dir + "/console (static, served by the proxy)",
"no service: it is a page, not a program",
},
})
}
}
if s := o.Shape(Webmail); s != Skip {
switch s {
case Container:
p.Steps = append(p.Steps, Step{
Title: "Start the webmail as a container",
Detail: []string{
"image: registry.coffeylabs.org/inbuxa/ihasmail-inbuxa (pinned by digest)",
"port: 8080 on loopback, behind the proxy",
"secret: the OAuth client secret from first boot, written once",
},
})
case Host:
p.Steps = append(p.Steps, Step{
Title: "Install the webmail on this machine",
Detail: []string{
"files: " + o.Dir + "/webmail, from the release tarball",
"user: inbuxa-webmail (system, no login)",
"unit: /etc/systemd/system/inbuxa-webmail.service, listening on 127.0.0.1:8080",
},
})
}
}
if !o.Local {
switch o.Proxy {
case "caddy":
p.Ports = append(p.Ports, 80, 443)
p.Steps = append(p.Steps, Step{
Title: "Put a proxy in front, with certificates",
Detail: []string{
"caddy, managed by the installer",
"names: " + strings.Join(o.hostnames(), ", "),
"ports: 80 and 443",
},
})
case "snippets":
p.Steps = append(p.Steps, Step{
Title: "Write proxy configuration for the web server already here",
Detail: []string{
o.Dir + "/proxy/nginx-inbuxa.conf and " + o.Dir + "/proxy/Caddyfile.fragment",
"nothing is loaded or restarted: that stays yours",
},
})
}
}
p.Steps = append(p.Steps, Step{
Title: "Check it works",
Detail: []string{
"the server answers JMAP and reports its version",
"each front end answers, and points at the server it was configured with",
"the ports that should be open are, and the ones that should not are not",
},
})
p.DNS = o.dnsRecords()
for _, held := range f.PortsHeld(p.Ports...) {
who := held.Holder
if who == "" {
who = "something this user cannot see"
}
p.Warnings = append(p.Warnings, fmt.Sprintf("port %d (%s) is held by %s", held.Number, held.For, who))
}
return p, nil
}
func (o Options) hostnames() []string {
var names []string
if o.Shape(Server) != Skip {
names = append(names, o.MailHost)
}
if o.Shape(Console) != Skip {
names = append(names, o.ConsoleHost)
}
if o.Shape(Webmail) != Skip {
names = append(names, o.WebmailHost)
}
return names
}
func (o Options) dnsRecords() []string {
if o.Local || o.Domain == "" {
return nil
}
var r []string
if o.Shape(Server) != Skip {
r = append(r,
fmt.Sprintf("%-28s MX 10 %s.", o.Domain+".", o.MailHost),
fmt.Sprintf("%-28s A this machine", o.MailHost+"."),
fmt.Sprintf("%-28s TXT \"v=spf1 mx -all\"", o.Domain+"."),
fmt.Sprintf("%-28s TXT the DKIM key first boot generates", "*._domainkey."+o.Domain+"."),
fmt.Sprintf("%-28s TXT \"v=DMARC1; p=reject; rua=mailto:postmaster@%s\"", "_dmarc."+o.Domain+".", o.Domain),
)
}
if o.Shape(Console) != Skip {
r = append(r, fmt.Sprintf("%-28s A this machine", o.ConsoleHost+"."))
}
if o.Shape(Webmail) != Skip {
r = append(r, fmt.Sprintf("%-28s A this machine", o.WebmailHost+"."))
}
r = append(r, "(first boot writes the exact records, including the keys, to dns.zone)")
return r
}
// String renders the plan the way the fifth screen and --dry-run show it.
func (p Plan) String() string {
var b strings.Builder
o := p.Options
fmt.Fprintf(&b, "Plan for %s\n\n", describe(o))
for i, s := range p.Steps {
fmt.Fprintf(&b, "%2d. %s\n", i+1, s.Title)
for _, d := range s.Detail {
fmt.Fprintf(&b, " %s\n", d)
}
}
if len(p.Ports) > 0 {
fmt.Fprintf(&b, "\nPorts it will bind: %s\n", joinInts(p.Ports))
}
if len(p.DNS) > 0 {
b.WriteString("\nThe domain will need:\n")
for _, r := range p.DNS {
fmt.Fprintf(&b, " %s\n", r)
}
}
if len(p.Warnings) > 0 {
b.WriteString("\nWorth reading first:\n")
for _, w := range p.Warnings {
fmt.Fprintf(&b, " - %s\n", w)
}
}
return b.String()
}
func describe(o Options) string {
var parts []string
for _, c := range []Component{Server, Console, Webmail} {
if s := o.Shape(c); s != Skip {
parts = append(parts, fmt.Sprintf("%s as a %s install", names[c], s))
}
}
where := o.Domain
if o.Local {
where = "a loopback evaluation"
}
return strings.Join(parts, ", ") + " -- " + where
}
func joinInts(n []int) string {
seen := map[int]bool{}
var out []string
for _, i := range n {
if seen[i] {
continue
}
seen[i] = true
out = append(out, fmt.Sprint(i))
}
return strings.Join(out, ", ")
}