Files
gotenberg/internal/pkg/prinery/chrome.go
2019-09-23 18:29:24 +02:00

328 lines
9.0 KiB
Go

package prinery
import (
"context"
"fmt"
"io/ioutil"
"time"
"github.com/mafredri/cdp"
"github.com/mafredri/cdp/devtool"
"github.com/mafredri/cdp/protocol/network"
"github.com/mafredri/cdp/protocol/page"
"github.com/mafredri/cdp/protocol/target"
"github.com/mafredri/cdp/rpcc"
"github.com/thecodingmachine/gotenberg/internal/pkg/xerrgroup"
"github.com/thecodingmachine/gotenberg/internal/pkg/xerror"
"github.com/thecodingmachine/gotenberg/internal/pkg/xlog"
"github.com/thecodingmachine/gotenberg/internal/pkg/xtime"
)
type chromeProcess struct {
devtPort uint
}
func newChromeProcesses(nInstances int64) []process {
processes := make([]process, nInstances)
var i int64
var currentPort uint = 9222
for i = 0; i < nInstances; i++ {
processes[i] = chromeProcess{
devtPort: currentPort,
}
currentPort++
}
return processes
}
func (p chromeProcess) id() string {
return fmt.Sprintf("%s-%d", p.binary(), p.port())
}
func (p chromeProcess) host() string {
return "127.0.0.1"
}
func (p chromeProcess) port() uint {
return p.devtPort
}
func (p chromeProcess) spec() processSpec {
return p
}
func (p chromeProcess) binary() string {
return "google-chrome-stable"
}
func (p chromeProcess) args() []string {
return []string{
"--no-sandbox",
"--headless",
// see https://github.com/GoogleChrome/puppeteer/issues/2410.
"--font-render-hinting=medium",
fmt.Sprintf("--remote-debugging-port=%d", p.port()),
"--disable-gpu",
"--disable-translate",
"--disable-extensions",
"--disable-background-networking",
"--safebrowsing-disable-auto-update",
"--disable-sync",
"--disable-default-apps",
"--hide-scrollbars",
"--metrics-recording-only",
"--mute-audio",
"--no-first-run",
}
}
func (p chromeProcess) warmupTime() time.Duration {
return 10 * time.Second
}
func (p chromeProcess) viabilityFunc() func(logger xlog.Logger) bool {
const op string = "prinery.chromeProcess.viabilityFunc"
return func(logger xlog.Logger) bool {
ctx, cancel := context.WithCancel(context.Background())
defer cancel()
endpoint := fmt.Sprintf("http://%s:%d" /*p.host()*/, "localhost", p.port())
logger.DebugfOp(
op,
"checking '%s' viability via endpoint '%s/json/version'",
p.id(),
endpoint,
)
v, err := devtool.New(endpoint).Version(ctx)
if err != nil {
logger.ErrorfOp(
op,
"'%s' is not viable as endpoint returned '%v'",
p.id(),
err,
)
return false
}
logger.DebugfOp(
op,
"'%s' is viable as endpoint returned '%v'",
p.id(),
v,
)
return true
}
}
type chromePrinter struct {
logger xlog.Logger
url string
opts ChromePrintOptions
}
func (p chromePrinter) print(ctx context.Context, spec processSpec, dest string) error {
const op string = "prinery.chromePrinter.print"
resolver := func() error {
devtEndpoint := fmt.Sprintf("http://%s:%d", spec.host(), spec.port())
devt, err := devtool.New(devtEndpoint).Version(ctx)
if err != nil {
return err
}
// connect to WebSocket URL (page) that speaks the Chrome DevTools Protocol.
devtConn, err := rpcc.DialContext(ctx, devt.WebSocketDebuggerURL)
if err != nil {
return err
}
defer devtConn.Close() // nolint: errcheck
// create a new CDP Client that uses conn.
devtClient := cdp.NewClient(devtConn)
newContextTarget, err := devtClient.Target.CreateBrowserContext(ctx)
if err != nil {
return err
}
/*
close the browser context when done.
we're not using the "default" context
as it may timeout before actually closing
the browser context.
see: https://github.com/mafredri/cdp/issues/101#issuecomment-524533670
*/
disposeBrowserContextArgs := target.NewDisposeBrowserContextArgs(newContextTarget.BrowserContextID)
defer devtClient.Target.DisposeBrowserContext(context.Background(), disposeBrowserContextArgs) // nolint: errcheck
// create a new blank target with the new browser context.
createTargetArgs := target.
NewCreateTargetArgs("about:blank").
SetBrowserContextID(newContextTarget.BrowserContextID)
newTarget, err := devtClient.Target.CreateTarget(ctx, createTargetArgs)
if err != nil {
return err
}
// connect the client to the new target.
newTargetWsURL := fmt.Sprintf("ws://%s:%d/devtools/page/%s", spec.host(), spec.port(), newTarget.TargetID)
newContextConn, err := rpcc.DialContext(ctx, newTargetWsURL)
if err != nil {
return err
}
defer newContextConn.Close() // nolint: errcheck
// create a new CDP Client that uses newContextConn.
targetClient := cdp.NewClient(newContextConn)
/*
close the target when done.
we're not using the "default" context
as it may timeout before actually closing
the target.
see: https://github.com/mafredri/cdp/issues/101#issuecomment-524533670
*/
closeTargetArgs := target.NewCloseTargetArgs(newTarget.TargetID)
defer targetClient.Target.CloseTarget(context.Background(), closeTargetArgs) // nolint: errcheck
// enable all events.
if err := p.enableEvents(ctx, targetClient); err != nil {
return err
}
// listen for all events.
if err := p.listenEvents(ctx, targetClient); err != nil {
return err
}
// apply a wait delay (if any).
if p.opts.WaitDelay > 0.0 {
// wait for a given amount of time (useful for javascript delay).
p.logger.DebugfOp(op, "applying a wait delay of '%.2fs'...", p.opts.WaitDelay)
time.Sleep(xtime.Duration(p.opts.WaitDelay))
} else {
p.logger.DebugOp(op, "no wait delay to apply, moving on...")
}
// print the page to PDF.
print, err := targetClient.Page.PrintToPDF(
ctx,
page.NewPrintToPDFArgs().
SetPaperWidth(p.opts.PaperWidth).
SetPaperHeight(p.opts.PaperHeight).
SetMarginTop(p.opts.MarginTop).
SetMarginBottom(p.opts.MarginBottom).
SetMarginLeft(p.opts.MarginLeft).
SetMarginRight(p.opts.MarginRight).
SetLandscape(p.opts.Landscape).
SetDisplayHeaderFooter(true).
SetHeaderTemplate(p.opts.HeaderHTML).
SetFooterTemplate(p.opts.FooterHTML).
SetPrintBackground(true),
)
if err != nil {
return err
}
if err := ioutil.WriteFile(dest, print.Data, 0644); err != nil {
return err
}
return nil
}
if err := resolver(); err != nil {
return xerror.New(op, err)
}
return nil
}
func (p chromePrinter) enableEvents(ctx context.Context, client *cdp.Client) error {
const op string = "prinery.chromePrinter.enableEvents"
// enable all the domain events that we're interested in.
if err := xerrgroup.Run(
func() error { return client.DOM.Enable(ctx) },
func() error { return client.Network.Enable(ctx, network.NewEnableArgs()) },
func() error { return client.Page.Enable(ctx) },
func() error {
return client.Page.SetLifecycleEventsEnabled(ctx, page.NewSetLifecycleEventsEnabledArgs(true))
},
func() error { return client.Runtime.Enable(ctx) },
); err != nil {
return xerror.New(op, err)
}
return nil
}
func (p chromePrinter) listenEvents(ctx context.Context, client *cdp.Client) error {
const op string = "prinery.chromePrinter.listenEvents"
resolver := func() error {
// make sure Page events are enabled.
if err := client.Page.Enable(ctx); err != nil {
return err
}
// make sure Network events are enabled.
if err := client.Network.Enable(ctx, nil); err != nil {
return err
}
// create all clients for events.
domContentEventFired, err := client.Page.DOMContentEventFired(ctx)
if err != nil {
return err
}
defer domContentEventFired.Close() // nolint: errcheck
loadEventFired, err := client.Page.LoadEventFired(ctx)
if err != nil {
return err
}
defer loadEventFired.Close() // nolint: errcheck
lifecycleEvent, err := client.Page.LifecycleEvent(ctx)
if err != nil {
return err
}
defer lifecycleEvent.Close() // nolint: errcheck
loadingFinished, err := client.Network.LoadingFinished(ctx)
if err != nil {
return err
}
defer loadingFinished.Close() // nolint: errcheck
if _, err := client.Page.Navigate(ctx, page.NewNavigateArgs(p.url)); err != nil {
return err
}
// wait for all events.
return xerrgroup.Run(
func() error {
_, err := domContentEventFired.Recv()
if err != nil {
return err
}
p.logger.DebugOp(op, "event 'domContentEventFired' received")
return nil
},
func() error {
_, err := loadEventFired.Recv()
if err != nil {
return err
}
p.logger.DebugOp(op, "event 'loadEventFired' received")
return nil
},
func() error {
const networkIdleEventName string = "networkIdle"
for {
ev, err := lifecycleEvent.Recv()
if err != nil {
return err
}
p.logger.DebugfOp(op, "event '%s' received", ev.Name)
if ev.Name == networkIdleEventName {
break
}
}
return nil
},
func() error {
_, err := loadingFinished.Recv()
if err != nil {
return err
}
p.logger.DebugOp(op, "event 'loadingFinished' received")
return nil
},
)
}
if err := resolver(); err != nil {
return xerror.New(op, err)
}
return nil
}
// Compile-time checks to ensure type implements desired interfaces.
var (
_ = processSpec(new(chromeProcess))
_ = process(new(chromeProcess))
_ = printer(new(chromePrinter))
)