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Merged
merged 5 commits into from
Jan 3, 2018
Merged

HUB_HOST and HUB_PORT to handle hub and nodes #640

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9a29879
Introducing HUB_HOST and HUB_PORT to start deprecating HUB_PORT_4444_…
diemol Dec 17, 2017
8806d1c
Updating main README to introduce HUB_HOST, HUB_PORT and more ways to…
diemol Dec 17, 2017
b968a4d
Adding missing --net in the command
diemol Dec 17, 2017
ac08f0d
Being more accurate in the docker run example.
diemol Dec 17, 2017
1b5fddc
Missed part of the command example.
diemol Dec 17, 2017
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14 changes: 13 additions & 1 deletion NodeBase/entry_point.sh
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Original file line number Diff line number Diff line change
Expand Up @@ -10,8 +10,20 @@ if [ ! -e /opt/selenium/config.json ]; then
exit 1
fi

# In the long term the idea is to remove $HUB_PORT_4444_TCP_ADDR and $HUB_PORT_4444_TCP_PORT and only work with
# $HUB_HOST and $HUB_PORT
if [ ! -z "$HUB_HOST" ]; then
HUB_PORT_PARAM=4444
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confused about a couple of things, why do you check

"if $HUB_HOST isn't empty, set port to 4444"

also, i see 4 variables...

HUB_HOST, HUB_PORT, HUB_HOST_PARAM, HUB_PORT_PARAM.

what's the differences between these? can';t we consolidate? make things a little simpler?

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@diemol diemol Dec 20, 2017 •
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No, no... There are only 3 variables: HUB_HOST, HUB_PORT and HUB_PORT_PARAM.

What I tried to do is to check first if HUB_HOST was set, if so then use HUB_PORT_PARAM as a placeholder for port 4444 (assuming that the user started the hub with port 4444).

Therefore they only will need to set HUB_HOST and the default port will be 4444. And in case they started the hub with a different port, then HUB_PORT would be set and HUB_PORT_PARAM takes its value.

It could be simplified by doing something like:

if [ ! -z "$HUB_HOST" ] && [ ! -z "$HUB_PORT" ]; then
  echo "Connecting to the Hub using the host ${HUB_HOST} and port ${HUB_PORT}"
  HUB_PORT_4444_TCP_ADDR=${HUB_HOST}
  HUB_PORT_4444_TCP_PORT=${HUB_PORT}
fi

So the user will need to set both variables always. I just thought it could be nicer when the user only needs to set HUB_HOST since in most of the cases people will use 4444 for hub.

What do you think?

if [ ! -z "$HUB_PORT" ]; then
HUB_PORT_PARAM=${HUB_PORT}
fi
echo "Connecting to the Hub using the host ${HUB_HOST} and port ${HUB_PORT_PARAM}"
HUB_PORT_4444_TCP_ADDR=${HUB_HOST}
HUB_PORT_4444_TCP_PORT=${HUB_PORT_PARAM}
fi

if [ -z "$HUB_PORT_4444_TCP_ADDR" ]; then
echo Not linked with a running Hub container 1>&2
echo "Not linked with a running Hub container" 1>&2
exit 1
fi

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14 changes: 13 additions & 1 deletion NodeDebug/entry_point.sh
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -12,8 +12,20 @@ if [ ! -e /opt/selenium/config.json ]; then
exit 1
fi

# In the long term the idea is to remove $HUB_PORT_4444_TCP_ADDR and $HUB_PORT_4444_TCP_PORT and only work with
# $HUB_HOST and $HUB_PORT
if [ ! -z "$HUB_HOST" ]; then
HUB_PORT_PARAM=4444
if [ ! -z "$HUB_PORT" ]; then
HUB_PORT_PARAM=${HUB_PORT}
fi
echo "Connecting to the Hub using the host ${HUB_HOST} and port ${HUB_PORT_PARAM}"
HUB_PORT_4444_TCP_ADDR=${HUB_HOST}
HUB_PORT_4444_TCP_PORT=${HUB_PORT_PARAM}
fi

if [ -z "$HUB_PORT_4444_TCP_ADDR" ]; then
echo Not linked with a running Hub container 1>&2
echo "Not linked with a running Hub container" 1>&2
exit 1
fi

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86 changes: 81 additions & 5 deletions README.md
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Original file line number Diff line number Diff line change
Expand Up @@ -41,7 +41,10 @@ $ docker run -d -p 4444:4444 -v /dev/shm:/dev/shm selenium/standalone-firefox:3.
#OR
$ docker run -d -p 4444:4444 --shm-size 2g selenium/standalone-firefox:3.8.1-bohrium
```
This is a known workaround to avoid the browser crashing inside a docker container, here are the documented issues for [Chrome](https://code.google.com/p/chromium/issues/detail?id=519952) and [Firefox](https://bugzilla.mozilla.org/show_bug.cgi?id=1338771#c10). The shm size of 2gb is arbitrary but known to work well, your specific use case might need a different value, it is recommended to tune this value according to your needs. Along the examples `-v /dev/shm:/dev/shm` will be used, but both are known to work.
This is a known workaround to avoid the browser crashing inside a docker container, here are the documented issues for
[Chrome](https://code.google.com/p/chromium/issues/detail?id=519952) and [Firefox](https://bugzilla.mozilla.org/show_bug.cgi?id=1338771#c10).
The shm size of 2gb is arbitrary but known to work well, your specific use case might need a different value, it is recommended
to tune this value according to your needs. Along the examples `-v /dev/shm:/dev/shm` will be used, but both are known to work.


### Standalone Chrome and Firefox
Expand All @@ -57,6 +60,68 @@ _Note: Only one standalone image can run on port_ `4444` _at a time._
To inspect visually what the browser is doing use the `standalone-chrome-debug` or `standalone-firefox-debug` images. See [Debugging](#debugging) section for details.

### Selenium Grid Hub and Nodes
There are different ways to run the images and create a grid, check the following options.

#### Using docker networking
With this option, the hub and nodes will be created in the same network and they will recognize each other by their container name.
A docker [network](https://docs.docker.com/engine/reference/commandline/network_create/) needs to be created as a first step.

``` bash
$ docker network create grid
$ docker run -d -p 4444:4444 --net grid --name selenium-hub selenium/hub:3.8.1-bohrium
$ docker run -d --net grid -e HUB_HOST=selenium-hub -v /dev/shm:/dev/shm selenium/node-chrome:3.8.1-bohrium
$ docker run -d --net grid -e HUB_HOST=selenium-hub -v /dev/shm:/dev/shm selenium/node-firefox:3.8.1-bohrium
```

When you are done using the grid and the containers have exited, the network can be removed with the following command:

``` bash
# Remove all unused networks
$ docker network prune
# OR
# Removes the grid network
$ docker network rm grid
```

#### Via docker-compose
The most simple way to start a grid is with [docker-compose](https://docs.docker.com/compose/overview/), use the following
snippet as your `docker-compose.yaml`, save it locally and in the same folder run `docker-compose up`.

```yaml
# To execute this docker-compose yml file use docker-compose -f <file_name> up
# Add the "-d" flag at the end for deattached execution
version: '2'
services:
firefox:
image: selenium/node-firefox:3.8.1-bohrium
volumes:
- /dev/shm:/dev/shm
depends_on:
- hub
environment:
HUB_HOST: hub

chrome:
image: selenium/node-chrome:3.8.1-bohrium
volumes:
- /dev/shm:/dev/shm
depends_on:
- hub
environment:
HUB_HOST: hub

hub:
image: selenium/hub:3.8.1-bohrium
ports:
- "4444:4444"
```

To stop the grid and cleanup the created containers, run `docker-compose down`.

#### Using `--link`
This option can be used for a single host scenario (hub and nodes running in a single machine), but it is not recommended
for longer term usage since this is a a docker [legacy feature](https://docs.docker.com/compose/compose-file/#links).
It could serve you as an option for a proof of concept, and for simplicity it is used in the examples shown from now on.

``` bash
$ docker run -d -p 4444:4444 --name selenium-hub selenium/hub:3.8.1-bohrium
Expand All @@ -82,13 +147,24 @@ You can pass `SE_OPTS` variable with additional commandline parameters for start
$ docker run -d -p 4444:4444 -e SE_OPTS="-debug true" --name selenium-hub selenium/hub:3.8.1-bohrium
```

### HUB_PORT_4444_TCP_ADDR and HUB_PORT_4444_TCP_PORT Selenium Node Configuration options
### Selenium Hub and Node Configuration options

For special network configurations or when the hub and the nodes are running on different machines `HUB_HOST` and `HUB_PORT`
or `REMOTE_HOST` can be used.

You can pass the `HUB_HOST` and `HUB_PORT` options to provide the hub address to a node when needed.

``` bash
# Assuming a hub was already started
$ docker run -d -e HUB_HOST=<hub_ip|hub_name> -e HUB_PORT=4444 selenium/node-chrome:3.8.1-bohrium
```

You can pass `HUB_PORT_4444_TCP_ADDR` and `HUB_PORT_4444_TCP_PORT` options to provide the hub address to a node when needed.
Some network topologies might prevent the hub to reach the node through the url given at registration time, `REMOTE_HOST`
can be used to supply the hub a url where the node is reachable under your specific network configuration

``` bash
$ docker run -d -p 4444:4444 -e HUB_PORT_4444_TCP_ADDR=10.10.1.10 -e HUB_PORT_4444_TCP_PORT=4444 \
--name selenium-hub selenium/node-chrome:3.8.1-bohrium
# Assuming a hub was already started
$ docker run -d -e HUB_HOST=<hub_ip|hub_name> -e REMOTE_HOST="http://node_ip|node_name:node_port" selenium/node-firefox:3.8.1-bohrium
```

## Building the images
Expand Down