path: root/docs/part-2/1_xds-server.md

# XDS - X(cross) Development System Server

`xds-server` is a web server that allows user to remotely cross build applications.

The first goal is to provide a multi-platform cross development tool with
near-zero installation.
The second goal is to keep application sources locally (on user's machine) to
make it compatible with existing IT policies (e.g. corporate backup or SCM),
and let user to continue to work as usual (use his favorite editor,
keep performance while editing/browsing sources).

This powerful and portable webserver (written in [Go](https://golang.org))
exposes a REST interface over HTTP.

`xds-server` uses [Syncthing](https://syncthing.net/) tool to synchronize
projects files from user machine to build server machine or container.

`xds-server` is commonly running on a build server (within a container or not)
and [xds-agent](2_xds-agent.md) must run on the developer/user machine in order
to setup the following connection chain:

```schema
    developer/user machine  |  build server or container
 ---------------------------|-----------------------------
  xds-cli <---> xds-agent <-|-> xds-server
```

**SEE ALSO**: [xds-cli](https://github.com/iotbzh/xds-cli),
a command-line tool that allows you to send commands to `xds-agent / xds-server`
and for example build your application from command-line or from your favorite
IDE (such as Netbeans or Visual Studio Code) through `xds-agent <=> xds-server`.

## How to run

`xds-server` has been designed to easily compile and debug
[AGL](https://www.automotivelinux.org/) applications. That's why `xds-server` has
been integrated into AGL SDK docker container.

>**Note:** For more info about AGL SDK docker container, please refer to
[AGL SDK Quick Setup](http://docs.automotivelinux.org/docs/getting_started/en/dev/reference/setup-sdk-environment.html)

### Get the container

Load the pre-build AGL SDK docker image including `xds-server`:

```bash
seb@laptop ~$ wget -O - http://iot.bzh/download/public/2017/XDS/docker/docker_agl_worker-xds-latest.tar.xz | docker load
```

### List container

You should get `docker.automotivelinux.org/agl/worker-xds:X.Y` image

```bash
# List image that we just built
seb@laptop ~$ docker images | grep worker-xds

docker.automotivelinux.org/agl/worker-xds       3.99.1              786d65b2792c        6 days ago          602MB
```

### Start xds-server within the container

Use provided script to create a new docker image and start a new container:

```bash
# Get script
seb@laptop ~$ wget https://raw.githubusercontent.com/iotbzh/xds-server/master/scripts/xds-docker-create-container.sh

# Create new XDS worker container
seb@laptop ~$ bash ./xds-docker-create-container.sh

# Check that new container is running
seb@laptop ~$ docker ps | grep worker-xds

b985d81af40c        docker.automotivelinux.org/agl/worker-xds:3.99.1       "/usr/bin/wait_for..."   6 days ago           Up 4 hours          0.0.0.0:8000->8000/tcp, 0.0.0.0:69->69/udp, 0.0.0.0:10809->10809/tcp, 0.0.0.0:2222->22/tcp    agl-xds-seb@laptop-0-seb
```

Note that you can also add a new shared directory using `--volume` option in order
to use for example with Path-Mapping folder type.

```bash
# Create new XDS worker container and share extra '$HOME/my-workspace' directory
seb@laptop ~$ bash ./xds-docker-create-container.sh --volume /my-workspace:$HOME/my-workspace
```

This container (ID=0) exposes following ports:

- 8000 : `xds-server` to serve XDS webapp
- 69   : TFTP
- 2222 : ssh

#### Manually setup docker user id

<!-- note -->
**Note:** if you used `xds-docker-create-container.sh` script to create XDS
docker container, user uid/gid inside docker has already been changed by this script.
<!-- endnote -->

If you plan to **use path-mapping sharing type for your projects**, you need to
have the same user id and group id inside and outside docker. By default user
and group name inside docker is set `devel` (id `1664`), use following commands
to replace id `1664` with your user/group id:

```bash
# Set docker container name to use (usually agl-xds-xxx where xxx is USERNAME@MACHINENAME-IDX-NAME)
seb@laptop ~$ export CONTAINER_NAME=agl-xds-seb@laptop-0-seb

# First kill all processes of devel user (including running xds-server)
seb@laptop ~$ docker exec ${CONTAINER_NAME} bash -c "/bin/loginctl kill-user devel"

# Change user and group id inside docker to match your ids
seb@laptop ~$ docker exec ${CONTAINER_NAME} bash -c "usermod -u $(id -u) devel"
seb@laptop ~$ docker exec ${CONTAINER_NAME} bash -c "groupmod -g $(id -g) devel"

# Update some files ownership
seb@laptop ~$ docker exec ${CONTAINER_NAME} bash -c "chown -R devel:devel /home/devel /tmp/xds*"

# Restart devel autologin service
seb@laptop ~$ docker exec ${CONTAINER_NAME} bash -c "systemctl start autologin"

# Restart xds-server as a service (ssh port 2222 may depend on your container ID)
seb@laptop ~$ ssh -p 2222 devel@localhost -- "systemctl --user start xds-server"
```

## Check if xds-server is running (open XDS webapp)

**`xds-server` is automatically started** as a service on container startup.

If the container is running on your localhost, you can access to a basic web
application:

```bash
seb@laptop ~$ xdg-open http://localhost:8000
```

If needed you can status / stop / start  it manually using following commands:

```bash
# Log into docker container
seb@laptop ~$ ssh -p 2222 devel@localhost

# Status XDS server:
devel@docker ~$ systemctl --user status xds-server.service

# Stop XDS server
devel@docker ~$ systemctl --user stop xds-server.service

# Start XDS server
devel@docker ~$ systemctl --user start xds-server.service

# Get XDS server logs
devel@docker ~$ journalctl --user --unit=xds-server.service --output=cat
```

### Manually Start XDS server

XDS server is started as a service by Systemd.

```bash
/lib/systemd/system/xds-server.service
```

This Systemd service starts a bash script `/opt/AGL/xds/server/xds-server-start.sh`

If you needed you can change default setting by defining specific environment
variables in `/etc/default/xds-server`.
For example to control log level, just set LOG_LEVEL env variable knowing that
supported *level* are: panic, fatal, error, warn, info, debug.

```bash
seb@laptop ~$ ssh -p 2222 devel@localhost
devel@docker ~$ echo 'LOG_LEVEL=debug' | sudo tee --append /etc/default/xds-server > /dev/null
devel@docker ~$ systemctl --user restart xds-server.service
devel@docker ~$ tail -f /tmp/xds-server/logs/xds-server.log
```

### Install SDK cross-toolchain

`xds-server` uses SDK cross-toolchain installed into directory pointed by
`sdkRootDir` setting (see configuration section below for more details).
For now, you need to install manually SDK cross toolchain. There are not embedded
into docker image by default because the size of these tarballs is too big.

Use provided `install-agl-sdks` script, for example to install SDK for ARM64 and
Intel corei7-64:

```bash
seb@laptop ~$ ssh -p 2222 devel@localhost

# Install ARM64 SDK (automatic download)
devel@docker ~$ sudo /opt/AGL/xds/server/xds-utils/install-agl-sdks.sh --arch aarch64

# Install Intel corei7-64 SDK (using an SDK tarball that has been built or downloaded manually)
devel@docker ~$ sudo /opt/AGL/xds/server/xds-utils/install-agl-sdks.sh --arch corei7-64 --file /tmp/poky-agl-glibc-x86_64-agl-demo-platform-crosssdk-corei7-64-toolchain-
3.99.1+snapshot.sh

```

### XDS server REST API and Web application

`xds-server` exposes a REST API and serves a basic web-application.

REST API based url is `http://localhost:8000/api/v1/` when XDS server is
running on your host (localhost) and basic web-application is available at
[http://localhost:8000](http://localhost:8000).

Just replace `localhost` by the host name or ip when `xds-server` is running
on another host.

```bash
# Get version using REST API
curl http://localhost:8000/api/v1/version

# Open browser and local xds-server web-application
xdg-open http://localhost:8000
```

Then follow instructions provided on this page to install and start `xds-agent`
that must run locally on your machine.

See also [xds-agent documentation](2_xds-agent.md) for more details.

## Build xds-server from scratch

### Dependencies

- Install and setup [Go](https://golang.org/doc/install) version 1.8.1 or higher to compile this tool.
- Install [npm](https://www.npmjs.com/)
- Install [nodejs](https://nodejs.org/en/)

Ubuntu:

```bash
 sudo apt-get install golang npm curl git zip unzip
 sudo npm install --global @angular/cli   # Angular Command Line Interface
 # Install LTS version of nodejs
 sudo n lts
```

openSUSE:

```bash
 sudo zypper install go npm git curl zip unzip
 sudo npm install --global @angular/cli   # Angular Command Line Interface
 # Install LTS version of nodejs
 sudo n lts
```

Don't forget to open new user session after installing the packages.

### Building

#### Native build

Create a GOPATH variable(must be a full path):

```bash
 export GOPATH=$(realpath ~/workspace_go)
```

Clone this repo into your `$GOPATH/src/github.com/iotbzh` and use delivered Makefile:

```bash
 mkdir -p $GOPATH/src/github.com/iotbzh
 cd $GOPATH/src/github.com/iotbzh
 git clone https://github.com/iotbzh/xds-server.git
 cd xds-server
 make all
```

And to install `xds-server` (by default in `/opt/AGL/xds/server`):

```bash
 make install
```

<!-- warning -->
**Warning:** makefile install rule and default values in configuration file are set
to fit the docker setup, so you may need to adapt some settings when you want to install
xds-server natively.
<!-- endwarning -->

<!-- note -->
**Note:** Used `DESTDIR` to specify another install directory

```bash
make install DESTDIR=$HOME/opt/xds-server
```

<!-- endnote -->

#### XDS docker image

As an alternative to a pre-build image, you can rebuild the container from scratch.
`xds-server` has been integrated as a flavour of AGL SDK docker image.
So to rebuild docker image just execute following commands:

```bash
# Clone docker-worker-generator git repo
git clone https://git.automotivelinux.org/AGL/docker-worker-generator
# Start build that will create a docker image
cd docker-worker-generator
make build FLAVOUR=xds
```

### Configuration

`xds-server` configuration is driven by a JSON config file (`config.json`).

Here is the logic to determine which `config.json` file will be used:

1. from command line option: `--config myConfig.json`
1. `$HOME/.xds-server/config.json` file
1. `/etc/xds-server/config.json` file
1. `<xds-server executable dir>/config.json` file

Supported fields in configuration file are (all fields are optional and example
below corresponds to the default values):

- **httpPort** : HTTP port of client webapp/REST API
- **webAppDir** : location of client web application (default: webapp/dist)
- **shareRootDir** : root directory where projects will be copied
- **logsDir**  : directory to store logs (eg. syncthing output)
- **sdkRootDir** : root directory where cross SDKs are installed
- **syncthing.binDir** : syncthing binaries directory (default: executable directory)
- **syncthing.home"** : syncthing home directory (usually .../syncthing-config)
- **syncthing.gui-address** : syncthing gui url (default <http://localhost:8385>)
- **syncthing.gui-apikey** : syncthing api-key to use (default auto-generated)

```json
{
    "httpPort": 8000,
    "webAppDir": "webapp/dist",
    "shareRootDir": "${HOME}/.xds-server/projects",
    "logsDir": "/tmp/logs",
    "sdkRootDir": "/xdt/sdk",
    "syncthing": {
        "binDir": "./bin",
        "home": "${HOME}/.xds-server/syncthing-config",
        "gui-address": "http://localhost:8385",
        "gui-apikey": "123456789",
    }
}
```

>**Note:** environment variables are supported by using `${MY_VAR}` syntax.

## Debugging

### XDS server architecture

The server part is written in *Go* and web app (basic HTML) in *Angular4*.

```bash
|
+-- bin/                where xds-server binary file will be built
|
+-- conf.d              Linux configuration and startup files (systemd user service)
|
+-- config.json.in      example of config.json file
|
+-- glide.yaml          Go package dependency file
|
+-- lib/                sources of server part (Go)
|
+-- main.go             main entry point of of Web server (Go)
|
+-- Makefile            makefile including
|
+-- README.md           this readme
|
+-- scripts/            hold various scripts used for installation or startup
|
+-- tools/              temporary directory to hold development tools (like glide)
|
+-- vendor/             temporary directory to hold Go dependencies packages
|
+-- webapp/             source client basic web application
```

Visual Studio Code launcher settings can be found into `.vscode/launch.json`.