mesh-delivery/modules/mesh-delivery-builder/internal/build/waits.go

package build

import (
	"context"
	"encoding/json"
	"errors"
	"fmt"
	"strings"
	"time"

	"git.novox.be/novox/mesh-delivery/contracts/go/seats/meshcatalog"
	"git.novox.be/novox/mesh-delivery/modules/mesh-delivery-builder/builds"
	sdkstep "git.novox.be/novox/mesh-delivery/sdk/buildstep"
)

// **The builder's toolchain wait** (design 47 G §672, §267, §276): the builder holds an entry while its fingerprint names a
// toolchain version of its language other than the one the agreed toolchain of that language names.
const (
	// WaitsTool is builder_waits, which reads the waits; ReleaseTool is builder_release, which builds the entry with the
	// running build module (§276), a hand act written in the hand-act log.
	WaitsTool   = "builder_waits"
	ReleaseTool = "builder_release"
	// WaitsState is the builder's old state section of the waits, one key <module>.<fingerprint>.
	WaitsState  = "waits"
	WaitsBucket = builds.BuilderModule + "_" + WaitsState
	// ModeRelease is the Mode of a reasks value of builder_release.
	ModeRelease = "release"
	// WaitRan ends a wait when a toolchain-agreed names the version; WaitReleased when builder_release ended it.
	WaitRan      = "ran"
	WaitReleased = "released"
)

// ToolchainWait is one wait: the entry's module and fingerprint, and the toolchain it waits for.
type ToolchainWait struct {
	Module      string    `json:"module"`
	Fingerprint string    `json:"fingerprint"`
	Language    string    `json:"language"`
	Version     string    `json:"version"`
	Since       time.Time `json:"since"`
}

// On is what the wait waits for, as the wait's `on` says it.
func (w ToolchainWait) On() string { return "toolchain:" + w.Language + "@" + w.Version }

// Waits keeps the builder's waits: Hold writes one in the state waits and says wait-held, once per wait; End deletes it and
// says wait-ended with how, and answers whether one was held.
type Waits interface {
	Hold(ctx context.Context, w ToolchainWait)
	End(ctx context.Context, module, fp, how string) bool
}

// toolchainWait is the toolchain wait of a module's fingerprint, or false when no language of its plan names a version
// other than the agreed one (a language with no agreed toolchain is not a wait of §672).
func (b *Builder) toolchainWait(module string, m meshcatalog.ModulesByModuleValue, plan Plan) (ToolchainWait, bool) {
	for _, bm := range plan.Modules() {
		if !plan.NeedsToolchain(bm) {
			continue
		}
		language, _ := b.Seats.LanguageOf(bm)
		ag := sdkstep.ToolchainAgreement(b.Toolchains.Entries(language))
		if want, ok := m.Toolchains[language]; ag.Wait == "" && ok && want.Version != ag.Toolchain.Version {
			return ToolchainWait{Module: module, Fingerprint: m.Fp2, Language: language, Version: want.Version, Since: b.now()}, true
		}
	}
	return ToolchainWait{}, false
}

// Release builds the held entry of module at fp with the running build module, now, and ends its wait released (design 47
// G §276, §672). It answers why nothing was done, or empty.
func (b *Builder) Release(ctx context.Context, module, fp, why, by string) string {
	b.init()
	key, err := builds.BuilderBuildKey(module, fp)
	if err != nil {
		return err.Error()
	}
	if b.Waits == nil {
		return "this builder keeps no waits"
	}
	b.mu.Lock()
	m, known := b.known[module]
	b.mu.Unlock()
	if !known || m.Fp2 != fp || m.Manifest == "" {
		return fmt.Sprintf("module %s does not have the fingerprint %s now: the builder builds the module's current fingerprint", module, fp)
	}
	b.mu.Lock()
	if b.released == nil {
		b.released = map[string]bool{}
	}
	b.released[key] = true
	b.mu.Unlock()
	if !b.Waits.End(ctx, module, fp, WaitReleased) {
		b.mu.Lock()
		delete(b.released, key)
		b.mu.Unlock()
		return fmt.Sprintf("%s holds no toolchain wait: %s builds a failed key again", key, BuildAgainTool)
	}
	b.logf("%s: released by %s (%s): built with the running build module", key, by, why)
	b.startOnce(ctx, key, module, m)
	return ""
}

func (b *Builder) isReleased(key string) bool {
	b.mu.Lock()
	defer b.mu.Unlock()
	return b.released[key]
}

func (b *Builder) unrelease(key string) {
	b.mu.Lock()
	delete(b.released, key)
	b.mu.Unlock()
}

// NewRelease is the value builder_release writes for a module's fingerprint: its key and the value.
func NewRelease(module, fp, why, by string, at time.Time) (string, []byte, error) {
	key, err := builds.BuilderBuildKey(module, fp)
	if err != nil {
		return "", nil, err
	}
	if strings.TrimSpace(why) == "" {
		return "", nil, errors.New("say why the entry is released (why)")
	}
	data, err := json.Marshal(ReAsk{V: 1, Why: strings.TrimSpace(why), By: by, At: at.UTC(), Mode: ModeRelease, Module: module, FP: fp})
	return key, data, err
}