Web Page Replay

Web Page Replay (WprGo) is a performance testing tool written in Golang for recording and replaying web pages. WprGo is currently used in Telemetry for Chrome benchmarking purposes. This requires go 1.8 and above. This has not been tested with earlier versions of go. It is supported on Windows, MacOS and Linux.

For performance tests, this tool is generally not used directly. Instead, we use these instructions to record, and these instructions to replay.

Getting the code

The first way is to use go install. This will use your default GOPATH, which is typically $HOME/go:

go install go.chromium.org/webpagereplay@latest

The second way is to download the repository. Don't just git clone! Use depot_tools to set everything up correctly for you.

• Install Chromium depot_tools.
• Get webpagereplay code with all dependencies:

mkdir webpagereplay
cd webpagereplay
fetch webpagereplay
cd webpagereplay

Sample usage

Record mode

• Terminal 1:

  Start wpr in record mode. By default wpr uses both rsa and ecdsa certificates, or provide your certificate directly with --https-cert-file and --https-key-file parameters.

  cd path/to/webpagereplay
  go run src/wpr.go record --http-port=8080 --https-port=8081 /tmp/archive.wprgo
  

  ...

  Ctrl-C

• Terminal 2:

  google-chrome-beta --user-data-dir=$foo \
   --host-resolver-rules="MAP *:80 127.0.0.1:8080,MAP *:443 127.0.0.1:8081,EXCLUDE localhost"
   --ignore-certificate-errors-spki-list=PhrPvGIaAMmd29hj8BCZOq096yj7uMpRNHpn5PDxI6I=,2HcXCSKKJS0lEXLQEWhpHUfGuojiU0tiT5gOF9LP6IQ=
  

  ... wait for record servers to start

Replay mode

• Terminal 1:

  Start wpr in replay mode.

  cd path/to/webpagereplay
  go run src/wpr.go replay --http-port=8080 --https-port=8081 /tmp/archive.wprgo
  

• Terminal 2:

  google-chrome-beta --user-data-dir=$bar \
   --host-resolver-rules="MAP *:80 127.0.0.1:8080,MAP *:443 127.0.0.1:8081,EXCLUDE localhost"
   --ignore-certificate-errors-spki-list=PhrPvGIaAMmd29hj8BCZOq096yj7uMpRNHpn5PDxI6I=,2HcXCSKKJS0lEXLQEWhpHUfGuojiU0tiT5gOF9LP6IQ=
  

  ... wait for replay servers to start

  load the page

Running on Android

You will need a Linux host machine and an android device.

• Set up reverse port forwarding

adb reverse tcp:8080 tcp:8080
adb reverse tcp:8081 tcp:8081

• Set up command line arguments

build/android/adb_chrome_public_command_line --host-resolver-rules="MAP *:80 127.0.0.1:8080,MAP *:443 127.0.0.1:8081,EXCLUDE localhost" \
  --ignore-certificate-errors-spki-list=PhrPvGIaAMmd29hj8BCZOq096yj7uMpRNHpn5PDxI6I=,2HcXCSKKJS0lEXLQEWhpHUfGuojiU0tiT5gOF9LP6IQ=

• Run wpr.go as usual on the linux machine

(Optional) Installing test root CA

WebPageReplay uses self signed certificates for Https requests. To make Chrome trust these certificates, you can use --ignore-certificate-errors-spki-list like above. If that doesn't work, you may try installing a test certificate authority as a local trust anchor. Note: Please do this with care because installing the test root CA compromises your machine. This is currently only supported on Linux and Android.

Installing the test CA. Specify a --android-device-id if you'd like to install the root CA on an android device.

cd path/to/webpagereplay
go run src/wpr.go installroot

Uninstall the test CA. Specify a --android-device-id if you'd like to remove the root CA from an android device.

cd path/to/webpagereplay
go run src/wpr.go removeroot

Other use cases

Http-to-http2 proxy:

• Terminal 1:

cd path/to/webpagereplay
go run src/wpr.go replay --https-port=8081 --https-to-http-port=8082 \
  /tmp/archive.wprgo

• Terminal 2:

google-chrome-beta --user-data-dir=$foo \
  --host-resolver-rules="MAP *:443 127.0.0.1:8081,EXCLUDE localhost" \
  --ignore-certificate-errors-spki-list=PhrPvGIaAMmd29hj8BCZOq096yj7uMpRNHpn5PDxI6I=,2HcXCSKKJS0lEXLQEWhpHUfGuojiU0tiT5gOF9LP6IQ= \
  --proxy-server=http=https://127.0.0.1:8082 \
  --trusted-spdy-proxy=127.0.0.1:8082

Inspecting an archive

httparchive.go is a convenient script to inspect a wprgo archive. Use ls,cat and edit. Options are available to specify request url host (--host) and path (--full-path).

E.g.

cd path/to/webpagereplay
go run src/httparchive.go ls /tmp/archive.wprgo --host=example.com --full-path=/index.html

Altering an archive

httparchive.go also provides methods to alter a wprgo archive. Use commands such as add, merge and trim. These will add new traffic, merge two archives to create a third, or trim request response pairs by host (--host) or path (--full-path). See --help for more information.

E.g.

cd path/to/webpagereplay
go run src/httparchive.go trim /tmp/archive.wprgo --host=example.com  /tmp/trimmed.wprgo

Running unit tests

Run all tests in a specific file. Use ‘-v’ flag to show results. Note: proxy_test requires more includes than just proxy.go.

cd path/to/webpagereplay/src/webpagereplay
go test archive_test.go archive.go
go test transformers_test.go transformers.go
go test proxy_test.go proxy.go transformers.go archive.go

Run all tests in webpagereplay module.

cd path/to/webpagereplay/src/webpagereplay
go test -run ''

Or

cd path/to/webpagereplay
go test -v go.chromium.org/webpagereplay/src/webpagereplay

Generate public key hash for --ignore-certificate-errors-spki-list

wpr_public_hash.txt is generated from wpr_cert.pem using the command below.

openssl x509 -noout -pubkey -in wpr_cert.pem | \
openssl pkey -pubin -outform der | \
openssl dgst -sha256 -binary | \
base64

Debugging WPR

The run_benchmark and record_wpr tools will build and invoke WPR from this directory if they are run with the --use-local-wpr flag.

Contribute

You can file bugs here. Patches welcome! Please run scripts/upload_new_binaries.py after making changes to go code.