mesh-catalog/modules/mesh-build-go/buildstep/seatgen/clients.go

package seatgen

import (
	"encoding/json"
	"fmt"
	"go/ast"
	"go/parser"
	"go/token"
	"os"
	"path/filepath"
	re "regexp"
	"sort"
	"strconv"
	"strings"

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

// ClientRoot is where a seat's hand-written client packages live (ADR 0625 §4, §5; ADR 0627): one directory per
// client, `go/clients/<seat without hyphens>client`, a Go module of its own (ADR 0625 §3), so the seat set's importers
// never import a client and a client's import of mesh-sdk forms no cycle. Compare leaves the tree to CheckClients.
const ClientRoot = "go/clients"

// RuntimeModule is mesh-sdk's Go module: the one module beside its own seat's contract a client may import (ADR 0625
// §3, §4).
const RuntimeModule = "git.novox.be/novox/mesh-sdk/go"

// ClientGoModule is the Go module of a seat's client, beside its contract's.
func ClientGoModule(root, seat string) string { return root + "/clients/" + pkgName(seat) + "client" }

// a module's tool address (`<module>.<tool_name>`) or call (`<module>.<tool>` written with an underscore).
var toolAddress = re.MustCompile(`^[a-z][a-z0-9-]*\.[a-z0-9]+_[a-z0-9_]+$`)

// CheckClients is ADR 0627 §3's catalog check of the clients, and ADR 0625 §5's rule for the files beside them: every
// directory under ClientRoot is the client of one seat defined whole, a Go module of its own at ClientGoModule; it
// imports only the standard library, its own seat's contract module and mesh-sdk's runtime (never another seat's
// contract or client); and no string in it names a module's subject (`mesh.mod.`), a module's tool, or another seat
// (its name, its subjects, its `seat:` call). Each problem is named once, sorted.
func CheckClients(dir string, m *Module) ([]string, error) {
	var out []string
	entries, err := os.ReadDir(filepath.Join(dir, ClientRoot))
	if os.IsNotExist(err) {
		return nil, nil
	}
	if err != nil {
		return nil, err
	}
	bySeatPkg := map[string]string{}
	for name, d := range m.Seats {
		if d.Grain == seatdef.Whole {
			bySeatPkg[pkgName(name)+"client"] = name
		}
	}
	for _, e := range entries {
		at := ClientRoot + "/" + e.Name()
		if !e.IsDir() {
			out = append(out, at+": a file under the clients' root, in no client")
			continue
		}
		seat, ok := bySeatPkg[e.Name()]
		if !ok {
			out = append(out, at+": the client of no seat defined whole (a client is `<seat without hyphens>client`)")
			continue
		}
		mod, err := os.ReadFile(filepath.Join(dir, at, "go.mod"))
		want := "module " + ClientGoModule(m.GoModule, seat)
		if err != nil || strings.SplitN(string(mod), "\n", 2)[0] != want {
			out = append(out, at+"/go.mod: not "+strconv.Quote(want)+": a client is a Go module of its own (ADR 0625 §3)")
		}
		problems, err := checkClient(dir, at, seat, m)
		if err != nil {
			return nil, err
		}
		out = append(out, problems...)
	}
	sort.Strings(out)
	return out, nil
}

func checkClient(dir, at, seat string, m *Module) ([]string, error) {
	var out []string
	own := SeatGoModule(m.GoModule, seat)
	others := map[string]bool{}
	for name := range m.Seats {
		if name != seat {
			others[name] = true
		}
	}
	namesOther := func(s string) bool {
		if others[s] {
			return true
		}
		for name := range others {
			if strings.HasPrefix(s, "mesh.seat."+name+".") || strings.HasPrefix(s, "seat:"+name+".") {
				return true
			}
		}
		return false
	}
	err := filepath.WalkDir(filepath.Join(dir, at), func(p string, e os.DirEntry, err error) error {
		if err != nil || e.IsDir() || !strings.HasSuffix(p, ".go") {
			return err
		}
		r := rel(dir, p)
		f, err := parser.ParseFile(token.NewFileSet(), p, nil, parser.SkipObjectResolution)
		if err != nil {
			return err
		}
		for _, im := range f.Imports {
			path, _ := strconv.Unquote(im.Path.Value)
			switch {
			case !strings.Contains(strings.SplitN(path, "/", 2)[0], "."):
			case path == own:
			case path == RuntimeModule || strings.HasPrefix(path, RuntimeModule+"/"):
			case strings.HasPrefix(path, m.GoModule+"/clients/"):
				out = append(out, r+": imports "+path+", another seat's client (ADR 0625 §4)")
			case path == m.GoModule || strings.HasPrefix(path, m.GoModule+"/"):
				out = append(out, r+": imports "+path+", not its own seat's contract (ADR 0625 §4)")
			default:
				out = append(out, r+": imports "+path+": a client uses only its seat's contract and mesh-sdk's runtime (ADR 0625 §3)")
			}
		}
		ast.Inspect(f, func(n ast.Node) bool {
			lit, ok := n.(*ast.BasicLit)
			if !ok || lit.Kind != token.STRING {
				return true
			}
			v, err := strconv.Unquote(lit.Value)
			if err != nil {
				return true
			}
			switch {
			case strings.HasPrefix(v, "mesh.mod."):
				out = append(out, fmt.Sprintf("%s: names a module's subject %q (ADR 0625 §4)", r, v))
			case toolAddress.MatchString(v):
				out = append(out, fmt.Sprintf("%s: names a module's tool %q (ADR 0625 §4)", r, v))
			case namesOther(v):
				out = append(out, fmt.Sprintf("%s: names another seat %q (ADR 0625 §4)", r, v))
			}
			return true
		})
		return nil
	})
	return out, err
}

// TSSetArtifact is the seat set's npm package artifact, at ts/.
const TSSetArtifact = "lib"

// CheckArtifacts is the check of module.json's package artifacts against the tree (ADR 0625 §1, §3), per language.
// Go: the root module is the artifact `go` at `go`, each seat defined whole the artifact `go-<seat without hyphens>`
// at its module's directory, each client present the artifact `go-<seat without hyphens>client` at its directory.
// npm: the seat set's package is the artifact `lib` at `ts`, each seat defined whole the artifact
// `ts-<seat without hyphens>` at TSSeatDir. No other package artifact of either language. Each problem is named once,
// sorted.
func CheckArtifacts(dir string, m *Module) ([]string, error) {
	raw, err := os.ReadFile(filepath.Join(dir, "module.json"))
	if err != nil {
		return nil, err
	}
	var mf struct {
		Build struct {
			Artifacts []struct {
				Name     string   `json:"name"`
				Kind     string   `json:"kind"`
				Language string   `json:"language"`
				Paths    []string `json:"paths"`
			} `json:"artifacts"`
		} `json:"build"`
	}
	if err := json.Unmarshal(raw, &mf); err != nil {
		return nil, fmt.Errorf("module.json: %w", err)
	}
	want := map[string]map[string]string{
		"go":         {"go": "go"},
		"typescript": {TSSetArtifact: "ts"},
	}
	for name, d := range m.Seats {
		if d.Grain == seatdef.Whole {
			want["go"]["go-"+pkgName(name)] = "go/seats/" + pkgName(name)
			want["typescript"]["ts-"+pkgName(name)] = TSSeatDir(name)
		}
	}
	if entries, err := os.ReadDir(filepath.Join(dir, ClientRoot)); err == nil {
		for _, e := range entries {
			if e.IsDir() {
				want["go"]["go-"+e.Name()] = ClientRoot + "/" + e.Name()
			}
		}
	}
	said := map[string]string{"go": "Go", "typescript": "npm"}
	var out []string
	seen := map[string]bool{}
	for _, a := range mf.Build.Artifacts {
		paths, lang := want[a.Language]
		if a.Kind != "package" || !lang {
			continue
		}
		seen[a.Language+"/"+a.Name] = true
		path, ok := paths[a.Name]
		switch {
		case !ok:
			out = append(out, "module.json: the "+said[a.Language]+" package artifact "+a.Name+" is no seat's module, no client's and not the seat set's")
		case len(a.Paths) != 1 || a.Paths[0] != path:
			out = append(out, fmt.Sprintf("module.json: the artifact %s's paths are %v, not [%s]", a.Name, a.Paths, path))
		}
	}
	for lang, paths := range want {
		for name, path := range paths {
			if !seen[lang+"/"+name] {
				out = append(out, "module.json: no "+said[lang]+" package artifact "+name+" for "+path)
			}
		}
	}
	sort.Strings(out)
	return out, nil
}