Package: zenoh-plugin-webserver
Version: 1.3.0
Architecture: arm64
Maintainer: zenoh-dev@eclipse.org
Installed-Size: 7176
Depends: zenohd (=1.3.0)
Filename: 1.3.0/zenoh-plugin-webserver_1.3.0_arm64.deb
Size: 1550084
MD5sum: 108edb1e80c15f642dc9fe4d0fd80c53
SHA1: 2e39fa474e61419ef103d9ef38adf04366db8725
SHA256: 5545ab17ff4cc295211e0292bf5d3445fd97993ebdedf6c8a3ed96a256201303
Section: net
Priority: optional
Homepage: http://zenoh.io
Description: Plugin for Zenoh implementing an HTTP server that maps URLs to zenoh key
expressions
.
[](https://github.com/eclipse-zenoh/zenoh-plugin-webserver/actions?query=workflow%3A%22CI%22)
[](https://github.com/eclipse-zenoh/roadmap/discussions)
[](https://discord.gg/2GJ958VuHs)
[](https://choosealicense.com/licenses/epl-2.0/)
[](https://opensource.org/licenses/Apache-2.0)
.
# Eclipse Zenoh
.
The Eclipse Zenoh: Zero Overhead Pub/sub, Store/Query and Compute.
.
Zenoh (pronounce _/zeno/_) unifies data in motion, data at rest and
computations. It carefully blends traditional pub/sub with geo-distributed
storages, queries and computations, while retaining a level of time and space
efficiency that is well beyond any of the mainstream stacks.
.
Check the website [zenoh.io](http://zenoh.io) and the
[roadmap](https://github.com/eclipse-zenoh/roadmap) for more detailed
information.
.
-------------------------------
.
# Web Server plugin
.
The Web Server plugin implements an HTTP server mapping URLs to zenoh keys.
This plugin can be used to set-up a Web server where the resources are
retrieved from geo-distributed
zenoh storages, each leveraging various backends (file system, database,
memory...).
.
**Library name** `zenoh_plugin_webserver`
.
:point_right: **Download stable versions:**
[https://download.eclipse.org/zenoh/zenoh-plugin-webserver/](https://download.eclipse.org/zenoh/zenoh-plugin-webserver/)
.
:point_right: **Build "main" branch:** see [below](#how-to-build-it)
.
-------------------------------
.
## :warning: Documentation for previous 0.5 versions
.
The following documentation related to the version currently in development in
"main" branch: 0.6.x.
.
For previous versions see the README and code of the corresponding tagged
version:
.
-
[0.5.0-beta.9](https://github.com/eclipse-zenoh/zenoh-plugin-webserver/tree/0.5.0-beta.9#readme)
-
[0.5.0-beta.8](https://github.com/eclipse-zenoh/zenoh-plugin-webserver/tree/0.5.0-beta.8#readme)
.
-------------------------------
.
## **Examples of usage**
.
Assuming you have a static website, you can:
.
- expose the files as zenoh key/values using the [File System
backend](https://github.com/eclipse-zenoh/zenoh-backend-filesystem)
- set-up this Web Server plugin that will allow HTTP clients to browse the
files.
.
Here are the steps:
.
1. Make sure the libraries for the File System backend and the Web Server
plugin are available for the zenoh router:
either installing their packages (depending your platform), either
downloading the library files corresponding
to your platform in your `~/.zenoh/lib` directory.
2. Copy the website files into a `~/.zenoh/zbackend_fs/my-site` directory (or
make it a symbolic link to the path of your website)
3. Create a `zenoh.json5` configuration file containing:
.
```json5
{
plugins: {
webserver: {
http_port: 8080,
},
storage_manager: {
volumes: {
fs: {}
},
storages: {
demo: {
key_expr: "my-site/**",
strip_prefix: "my-site",
volume: {
id: "fs",
dir: "my-site",
read_only: true
}
}
}
}
}
}
```
.
4. Start the zenoh router (`zenohd`). It will automatically load the Web Server
plugin and make it available on port 8080. It will also create a storage
replying to any zenoh query on key expressions starting with `my-site/`.
Now you can browse your site on
[http://localhost:8080/my-site](http://localhost:8080/my-site).
.
For more advanced use cases you can also:
.
- Have the files of your web sites stored on different hosts. Running a zenoh
router with a File System Storage on
each host allow to make all the files available under the `my-site/` zenoh
key.
- Duplicate the files of your web sites on several hosts to provide fault
tolerance.
- Start several zenoh routers with the Web Service plugin on different hosts
(not necessarly the same than the
hosts running the File System storages). Each host will serve your web site.
- Use other backends than the File System to store your resources and make them
available through zenoh.
(List of available backends
[here](http://zenoh.io/docs/manual/backends-list/)).
- Deploy a zenoh application that will implement `eval` function for a
resource, replying to requests with a
dynamic content (see the `z_eval` example in
[Rust](https://github.com/eclipse-zenoh/zenoh/blob/main/zenoh/examples/zenoh/z_eval.rs)
or
[Python](https://github.com/eclipse-zenoh/zenoh-python/blob/main/examples/zenoh/z_eval.py)).
.
-------------------------------
.
## **Configuration**
.
In its configuration part, the plugin supports those settings:
.
- **`http_port`** - int or string - required:
either a port number as an integer or a string, either a string with format
`":"`
.
-------------------------------
.
## **Troubleshooting**
.
### _Address already in use_
.
If in `zenohd` logs you see such error log at startup:
.
```raw
[2021-04-12T14:20:51Z ERROR zenoh_plugin_webserver] Unable to start http server
for REST : Os { code: 48, kind: AddrInUse, message: "Address already in use" }
```
.
It means another process is already using this port number that the webserver
plugin would like to use.
In such case, you have 2 solutions:
.
- stop the other process using this port
- make the webserver plugin to another port changing its `listener` option.
.
### _Permission denied_
.
If in `zenohd` logs you see such error log at startup:
.
```raw
[2021-04-12T13:55:10Z ERROR zenoh_plugin_webserver] Unable to start http server
for REST : Os { code: 13, kind: PermissionDenied, message: "Permission denied"
```
.
It probably means your OS (this usually happens on Linux) forbids the usage of
the configured port for non-root user (actually it usually restricts all ports
between 0 and 1024).
In such case, you have 2 solutions:
.
- run zenohd with root privileges (via `sudo`)
- use another changing he webserver plugin's `listener` option.
.
-------------------------------
.
## **How to build it**
.
> :warning: **WARNING** :warning: : Zenoh and its ecosystem are under active
development. When you build from git, make sure you also build from git any
other Zenoh repository you plan to use (e.g. binding, plugin, backend, etc.).
It may happen that some changes in git are not compatible with the most recent
packaged Zenoh release (e.g. deb, docker, pip). We put particular effort in
mantaining compatibility between the various git repositories in the Zenoh
project.
>
> :warning: **WARNING** :warning: : As Rust doesn't have a stable ABI, the
plugins should be
built with the exact same Rust version than `zenohd`, and using for `zenoh`
dependency the same version (or commit number) than 'zenohd'.
Otherwise, incompatibilities in memory mapping of shared types between `zenohd`
and the library can lead to a `"SIGSEV"` crash.
.
At first, install [Cargo and
Rust](https://doc.rust-lang.org/cargo/getting-started/installation.html). If
you already have the Rust toolchain installed, make sure it is up-to-date with:
.
```bash
rustup update
```
.
To know the Rust version you're `zenohd` has been built with, use the
`--version` option.
Example:
.
```bash
zenohd --version
The zenoh router v0.6.0-beta.1 built with rustc 1.64.0 (a55dd71d5 2022-09-19)
```
.
Here, `zenohd` has been built with the rustc version `1.64.0`.
Install and use this toolchain with the following command:
.
```bash
rustup default 1.64.0
```
.
And `zenohd` version corresponds to an un-released commit with id `1f20c86`.
Update the `zenoh` dependency in Cargo.lock with this command:
.
```bash
cargo update -p zenoh --precise 1f20c86
```
.
Then build the backend with:
.
```bash
cargo build --release -p zenoh-plugin-webserver
```
Package: zenoh-plugin-webserver
Version: 1.3.0
Architecture: amd64
Maintainer: zenoh-dev@eclipse.org
Installed-Size: 6962
Depends: zenohd (=1.3.0)
Filename: 1.3.0/zenoh-plugin-webserver_1.3.0_amd64.deb
Size: 1654632
MD5sum: c88c70e036bffc8430bfa9ffa95307db
SHA1: c32d73b9a694509e8d07a395a806fcc911af431f
SHA256: d5cf562eb8b6594215eedd765e648799d8ec928032bad47e6eed13360a02c6a1
Section: net
Priority: optional
Homepage: http://zenoh.io
Description: Plugin for Zenoh implementing an HTTP server that maps URLs to zenoh key
expressions
.
[](https://github.com/eclipse-zenoh/zenoh-plugin-webserver/actions?query=workflow%3A%22CI%22)
[](https://github.com/eclipse-zenoh/roadmap/discussions)
[](https://discord.gg/2GJ958VuHs)
[](https://choosealicense.com/licenses/epl-2.0/)
[](https://opensource.org/licenses/Apache-2.0)
.
# Eclipse Zenoh
.
The Eclipse Zenoh: Zero Overhead Pub/sub, Store/Query and Compute.
.
Zenoh (pronounce _/zeno/_) unifies data in motion, data at rest and
computations. It carefully blends traditional pub/sub with geo-distributed
storages, queries and computations, while retaining a level of time and space
efficiency that is well beyond any of the mainstream stacks.
.
Check the website [zenoh.io](http://zenoh.io) and the
[roadmap](https://github.com/eclipse-zenoh/roadmap) for more detailed
information.
.
-------------------------------
.
# Web Server plugin
.
The Web Server plugin implements an HTTP server mapping URLs to zenoh keys.
This plugin can be used to set-up a Web server where the resources are
retrieved from geo-distributed
zenoh storages, each leveraging various backends (file system, database,
memory...).
.
**Library name** `zenoh_plugin_webserver`
.
:point_right: **Download stable versions:**
[https://download.eclipse.org/zenoh/zenoh-plugin-webserver/](https://download.eclipse.org/zenoh/zenoh-plugin-webserver/)
.
:point_right: **Build "main" branch:** see [below](#how-to-build-it)
.
-------------------------------
.
## :warning: Documentation for previous 0.5 versions
.
The following documentation related to the version currently in development in
"main" branch: 0.6.x.
.
For previous versions see the README and code of the corresponding tagged
version:
.
-
[0.5.0-beta.9](https://github.com/eclipse-zenoh/zenoh-plugin-webserver/tree/0.5.0-beta.9#readme)
-
[0.5.0-beta.8](https://github.com/eclipse-zenoh/zenoh-plugin-webserver/tree/0.5.0-beta.8#readme)
.
-------------------------------
.
## **Examples of usage**
.
Assuming you have a static website, you can:
.
- expose the files as zenoh key/values using the [File System
backend](https://github.com/eclipse-zenoh/zenoh-backend-filesystem)
- set-up this Web Server plugin that will allow HTTP clients to browse the
files.
.
Here are the steps:
.
1. Make sure the libraries for the File System backend and the Web Server
plugin are available for the zenoh router:
either installing their packages (depending your platform), either
downloading the library files corresponding
to your platform in your `~/.zenoh/lib` directory.
2. Copy the website files into a `~/.zenoh/zbackend_fs/my-site` directory (or
make it a symbolic link to the path of your website)
3. Create a `zenoh.json5` configuration file containing:
.
```json5
{
plugins: {
webserver: {
http_port: 8080,
},
storage_manager: {
volumes: {
fs: {}
},
storages: {
demo: {
key_expr: "my-site/**",
strip_prefix: "my-site",
volume: {
id: "fs",
dir: "my-site",
read_only: true
}
}
}
}
}
}
```
.
4. Start the zenoh router (`zenohd`). It will automatically load the Web Server
plugin and make it available on port 8080. It will also create a storage
replying to any zenoh query on key expressions starting with `my-site/`.
Now you can browse your site on
[http://localhost:8080/my-site](http://localhost:8080/my-site).
.
For more advanced use cases you can also:
.
- Have the files of your web sites stored on different hosts. Running a zenoh
router with a File System Storage on
each host allow to make all the files available under the `my-site/` zenoh
key.
- Duplicate the files of your web sites on several hosts to provide fault
tolerance.
- Start several zenoh routers with the Web Service plugin on different hosts
(not necessarly the same than the
hosts running the File System storages). Each host will serve your web site.
- Use other backends than the File System to store your resources and make them
available through zenoh.
(List of available backends
[here](http://zenoh.io/docs/manual/backends-list/)).
- Deploy a zenoh application that will implement `eval` function for a
resource, replying to requests with a
dynamic content (see the `z_eval` example in
[Rust](https://github.com/eclipse-zenoh/zenoh/blob/main/zenoh/examples/zenoh/z_eval.rs)
or
[Python](https://github.com/eclipse-zenoh/zenoh-python/blob/main/examples/zenoh/z_eval.py)).
.
-------------------------------
.
## **Configuration**
.
In its configuration part, the plugin supports those settings:
.
- **`http_port`** - int or string - required:
either a port number as an integer or a string, either a string with format
`":"`
.
-------------------------------
.
## **Troubleshooting**
.
### _Address already in use_
.
If in `zenohd` logs you see such error log at startup:
.
```raw
[2021-04-12T14:20:51Z ERROR zenoh_plugin_webserver] Unable to start http server
for REST : Os { code: 48, kind: AddrInUse, message: "Address already in use" }
```
.
It means another process is already using this port number that the webserver
plugin would like to use.
In such case, you have 2 solutions:
.
- stop the other process using this port
- make the webserver plugin to another port changing its `listener` option.
.
### _Permission denied_
.
If in `zenohd` logs you see such error log at startup:
.
```raw
[2021-04-12T13:55:10Z ERROR zenoh_plugin_webserver] Unable to start http server
for REST : Os { code: 13, kind: PermissionDenied, message: "Permission denied"
```
.
It probably means your OS (this usually happens on Linux) forbids the usage of
the configured port for non-root user (actually it usually restricts all ports
between 0 and 1024).
In such case, you have 2 solutions:
.
- run zenohd with root privileges (via `sudo`)
- use another changing he webserver plugin's `listener` option.
.
-------------------------------
.
## **How to build it**
.
> :warning: **WARNING** :warning: : Zenoh and its ecosystem are under active
development. When you build from git, make sure you also build from git any
other Zenoh repository you plan to use (e.g. binding, plugin, backend, etc.).
It may happen that some changes in git are not compatible with the most recent
packaged Zenoh release (e.g. deb, docker, pip). We put particular effort in
mantaining compatibility between the various git repositories in the Zenoh
project.
>
> :warning: **WARNING** :warning: : As Rust doesn't have a stable ABI, the
plugins should be
built with the exact same Rust version than `zenohd`, and using for `zenoh`
dependency the same version (or commit number) than 'zenohd'.
Otherwise, incompatibilities in memory mapping of shared types between `zenohd`
and the library can lead to a `"SIGSEV"` crash.
.
At first, install [Cargo and
Rust](https://doc.rust-lang.org/cargo/getting-started/installation.html). If
you already have the Rust toolchain installed, make sure it is up-to-date with:
.
```bash
rustup update
```
.
To know the Rust version you're `zenohd` has been built with, use the
`--version` option.
Example:
.
```bash
zenohd --version
The zenoh router v0.6.0-beta.1 built with rustc 1.64.0 (a55dd71d5 2022-09-19)
```
.
Here, `zenohd` has been built with the rustc version `1.64.0`.
Install and use this toolchain with the following command:
.
```bash
rustup default 1.64.0
```
.
And `zenohd` version corresponds to an un-released commit with id `1f20c86`.
Update the `zenoh` dependency in Cargo.lock with this command:
.
```bash
cargo update -p zenoh --precise 1f20c86
```
.
Then build the backend with:
.
```bash
cargo build --release -p zenoh-plugin-webserver
```
Package: zenoh-plugin-webserver
Version: 1.3.0
Architecture: armel
Maintainer: zenoh-dev@eclipse.org
Installed-Size: 6499
Depends: zenohd (=1.3.0)
Filename: 1.3.0/zenoh-plugin-webserver_1.3.0_armel.deb
Size: 1526200
MD5sum: 49967bc59df421172b27a7c4b26cb724
SHA1: ea8027a67580b5b7ef0ce5f98ebe9164d65b23af
SHA256: 639ff3ecf7671bb4e1db10e88c2d87666f373db6047709cc97e0d68f4a766d70
Section: net
Priority: optional
Homepage: http://zenoh.io
Description: Plugin for Zenoh implementing an HTTP server that maps URLs to zenoh key
expressions
.
[](https://github.com/eclipse-zenoh/zenoh-plugin-webserver/actions?query=workflow%3A%22CI%22)
[](https://github.com/eclipse-zenoh/roadmap/discussions)
[](https://discord.gg/2GJ958VuHs)
[](https://choosealicense.com/licenses/epl-2.0/)
[](https://opensource.org/licenses/Apache-2.0)
.
# Eclipse Zenoh
.
The Eclipse Zenoh: Zero Overhead Pub/sub, Store/Query and Compute.
.
Zenoh (pronounce _/zeno/_) unifies data in motion, data at rest and
computations. It carefully blends traditional pub/sub with geo-distributed
storages, queries and computations, while retaining a level of time and space
efficiency that is well beyond any of the mainstream stacks.
.
Check the website [zenoh.io](http://zenoh.io) and the
[roadmap](https://github.com/eclipse-zenoh/roadmap) for more detailed
information.
.
-------------------------------
.
# Web Server plugin
.
The Web Server plugin implements an HTTP server mapping URLs to zenoh keys.
This plugin can be used to set-up a Web server where the resources are
retrieved from geo-distributed
zenoh storages, each leveraging various backends (file system, database,
memory...).
.
**Library name** `zenoh_plugin_webserver`
.
:point_right: **Download stable versions:**
[https://download.eclipse.org/zenoh/zenoh-plugin-webserver/](https://download.eclipse.org/zenoh/zenoh-plugin-webserver/)
.
:point_right: **Build "main" branch:** see [below](#how-to-build-it)
.
-------------------------------
.
## :warning: Documentation for previous 0.5 versions
.
The following documentation related to the version currently in development in
"main" branch: 0.6.x.
.
For previous versions see the README and code of the corresponding tagged
version:
.
-
[0.5.0-beta.9](https://github.com/eclipse-zenoh/zenoh-plugin-webserver/tree/0.5.0-beta.9#readme)
-
[0.5.0-beta.8](https://github.com/eclipse-zenoh/zenoh-plugin-webserver/tree/0.5.0-beta.8#readme)
.
-------------------------------
.
## **Examples of usage**
.
Assuming you have a static website, you can:
.
- expose the files as zenoh key/values using the [File System
backend](https://github.com/eclipse-zenoh/zenoh-backend-filesystem)
- set-up this Web Server plugin that will allow HTTP clients to browse the
files.
.
Here are the steps:
.
1. Make sure the libraries for the File System backend and the Web Server
plugin are available for the zenoh router:
either installing their packages (depending your platform), either
downloading the library files corresponding
to your platform in your `~/.zenoh/lib` directory.
2. Copy the website files into a `~/.zenoh/zbackend_fs/my-site` directory (or
make it a symbolic link to the path of your website)
3. Create a `zenoh.json5` configuration file containing:
.
```json5
{
plugins: {
webserver: {
http_port: 8080,
},
storage_manager: {
volumes: {
fs: {}
},
storages: {
demo: {
key_expr: "my-site/**",
strip_prefix: "my-site",
volume: {
id: "fs",
dir: "my-site",
read_only: true
}
}
}
}
}
}
```
.
4. Start the zenoh router (`zenohd`). It will automatically load the Web Server
plugin and make it available on port 8080. It will also create a storage
replying to any zenoh query on key expressions starting with `my-site/`.
Now you can browse your site on
[http://localhost:8080/my-site](http://localhost:8080/my-site).
.
For more advanced use cases you can also:
.
- Have the files of your web sites stored on different hosts. Running a zenoh
router with a File System Storage on
each host allow to make all the files available under the `my-site/` zenoh
key.
- Duplicate the files of your web sites on several hosts to provide fault
tolerance.
- Start several zenoh routers with the Web Service plugin on different hosts
(not necessarly the same than the
hosts running the File System storages). Each host will serve your web site.
- Use other backends than the File System to store your resources and make them
available through zenoh.
(List of available backends
[here](http://zenoh.io/docs/manual/backends-list/)).
- Deploy a zenoh application that will implement `eval` function for a
resource, replying to requests with a
dynamic content (see the `z_eval` example in
[Rust](https://github.com/eclipse-zenoh/zenoh/blob/main/zenoh/examples/zenoh/z_eval.rs)
or
[Python](https://github.com/eclipse-zenoh/zenoh-python/blob/main/examples/zenoh/z_eval.py)).
.
-------------------------------
.
## **Configuration**
.
In its configuration part, the plugin supports those settings:
.
- **`http_port`** - int or string - required:
either a port number as an integer or a string, either a string with format
`":"`
.
-------------------------------
.
## **Troubleshooting**
.
### _Address already in use_
.
If in `zenohd` logs you see such error log at startup:
.
```raw
[2021-04-12T14:20:51Z ERROR zenoh_plugin_webserver] Unable to start http server
for REST : Os { code: 48, kind: AddrInUse, message: "Address already in use" }
```
.
It means another process is already using this port number that the webserver
plugin would like to use.
In such case, you have 2 solutions:
.
- stop the other process using this port
- make the webserver plugin to another port changing its `listener` option.
.
### _Permission denied_
.
If in `zenohd` logs you see such error log at startup:
.
```raw
[2021-04-12T13:55:10Z ERROR zenoh_plugin_webserver] Unable to start http server
for REST : Os { code: 13, kind: PermissionDenied, message: "Permission denied"
```
.
It probably means your OS (this usually happens on Linux) forbids the usage of
the configured port for non-root user (actually it usually restricts all ports
between 0 and 1024).
In such case, you have 2 solutions:
.
- run zenohd with root privileges (via `sudo`)
- use another changing he webserver plugin's `listener` option.
.
-------------------------------
.
## **How to build it**
.
> :warning: **WARNING** :warning: : Zenoh and its ecosystem are under active
development. When you build from git, make sure you also build from git any
other Zenoh repository you plan to use (e.g. binding, plugin, backend, etc.).
It may happen that some changes in git are not compatible with the most recent
packaged Zenoh release (e.g. deb, docker, pip). We put particular effort in
mantaining compatibility between the various git repositories in the Zenoh
project.
>
> :warning: **WARNING** :warning: : As Rust doesn't have a stable ABI, the
plugins should be
built with the exact same Rust version than `zenohd`, and using for `zenoh`
dependency the same version (or commit number) than 'zenohd'.
Otherwise, incompatibilities in memory mapping of shared types between `zenohd`
and the library can lead to a `"SIGSEV"` crash.
.
At first, install [Cargo and
Rust](https://doc.rust-lang.org/cargo/getting-started/installation.html). If
you already have the Rust toolchain installed, make sure it is up-to-date with:
.
```bash
rustup update
```
.
To know the Rust version you're `zenohd` has been built with, use the
`--version` option.
Example:
.
```bash
zenohd --version
The zenoh router v0.6.0-beta.1 built with rustc 1.64.0 (a55dd71d5 2022-09-19)
```
.
Here, `zenohd` has been built with the rustc version `1.64.0`.
Install and use this toolchain with the following command:
.
```bash
rustup default 1.64.0
```
.
And `zenohd` version corresponds to an un-released commit with id `1f20c86`.
Update the `zenoh` dependency in Cargo.lock with this command:
.
```bash
cargo update -p zenoh --precise 1f20c86
```
.
Then build the backend with:
.
```bash
cargo build --release -p zenoh-plugin-webserver
```
Package: zenoh-plugin-webserver
Version: 1.3.0
Architecture: armhf
Maintainer: zenoh-dev@eclipse.org
Installed-Size: 6391
Depends: zenohd (=1.3.0)
Filename: 1.3.0/zenoh-plugin-webserver_1.3.0_armhf.deb
Size: 1522632
MD5sum: 732cc759065bc588870e38120b3fd5cc
SHA1: 8bfe5b791c45223c1a6aa78e30c239f956c888e7
SHA256: da4d343c6769a026ef14a8538d4d5e8557e411c9f00f752d7e7c9448c0d7c0f9
Section: net
Priority: optional
Homepage: http://zenoh.io
Description: Plugin for Zenoh implementing an HTTP server that maps URLs to zenoh key
expressions
.
[](https://github.com/eclipse-zenoh/zenoh-plugin-webserver/actions?query=workflow%3A%22CI%22)
[](https://github.com/eclipse-zenoh/roadmap/discussions)
[](https://discord.gg/2GJ958VuHs)
[](https://choosealicense.com/licenses/epl-2.0/)
[](https://opensource.org/licenses/Apache-2.0)
.
# Eclipse Zenoh
.
The Eclipse Zenoh: Zero Overhead Pub/sub, Store/Query and Compute.
.
Zenoh (pronounce _/zeno/_) unifies data in motion, data at rest and
computations. It carefully blends traditional pub/sub with geo-distributed
storages, queries and computations, while retaining a level of time and space
efficiency that is well beyond any of the mainstream stacks.
.
Check the website [zenoh.io](http://zenoh.io) and the
[roadmap](https://github.com/eclipse-zenoh/roadmap) for more detailed
information.
.
-------------------------------
.
# Web Server plugin
.
The Web Server plugin implements an HTTP server mapping URLs to zenoh keys.
This plugin can be used to set-up a Web server where the resources are
retrieved from geo-distributed
zenoh storages, each leveraging various backends (file system, database,
memory...).
.
**Library name** `zenoh_plugin_webserver`
.
:point_right: **Download stable versions:**
[https://download.eclipse.org/zenoh/zenoh-plugin-webserver/](https://download.eclipse.org/zenoh/zenoh-plugin-webserver/)
.
:point_right: **Build "main" branch:** see [below](#how-to-build-it)
.
-------------------------------
.
## :warning: Documentation for previous 0.5 versions
.
The following documentation related to the version currently in development in
"main" branch: 0.6.x.
.
For previous versions see the README and code of the corresponding tagged
version:
.
-
[0.5.0-beta.9](https://github.com/eclipse-zenoh/zenoh-plugin-webserver/tree/0.5.0-beta.9#readme)
-
[0.5.0-beta.8](https://github.com/eclipse-zenoh/zenoh-plugin-webserver/tree/0.5.0-beta.8#readme)
.
-------------------------------
.
## **Examples of usage**
.
Assuming you have a static website, you can:
.
- expose the files as zenoh key/values using the [File System
backend](https://github.com/eclipse-zenoh/zenoh-backend-filesystem)
- set-up this Web Server plugin that will allow HTTP clients to browse the
files.
.
Here are the steps:
.
1. Make sure the libraries for the File System backend and the Web Server
plugin are available for the zenoh router:
either installing their packages (depending your platform), either
downloading the library files corresponding
to your platform in your `~/.zenoh/lib` directory.
2. Copy the website files into a `~/.zenoh/zbackend_fs/my-site` directory (or
make it a symbolic link to the path of your website)
3. Create a `zenoh.json5` configuration file containing:
.
```json5
{
plugins: {
webserver: {
http_port: 8080,
},
storage_manager: {
volumes: {
fs: {}
},
storages: {
demo: {
key_expr: "my-site/**",
strip_prefix: "my-site",
volume: {
id: "fs",
dir: "my-site",
read_only: true
}
}
}
}
}
}
```
.
4. Start the zenoh router (`zenohd`). It will automatically load the Web Server
plugin and make it available on port 8080. It will also create a storage
replying to any zenoh query on key expressions starting with `my-site/`.
Now you can browse your site on
[http://localhost:8080/my-site](http://localhost:8080/my-site).
.
For more advanced use cases you can also:
.
- Have the files of your web sites stored on different hosts. Running a zenoh
router with a File System Storage on
each host allow to make all the files available under the `my-site/` zenoh
key.
- Duplicate the files of your web sites on several hosts to provide fault
tolerance.
- Start several zenoh routers with the Web Service plugin on different hosts
(not necessarly the same than the
hosts running the File System storages). Each host will serve your web site.
- Use other backends than the File System to store your resources and make them
available through zenoh.
(List of available backends
[here](http://zenoh.io/docs/manual/backends-list/)).
- Deploy a zenoh application that will implement `eval` function for a
resource, replying to requests with a
dynamic content (see the `z_eval` example in
[Rust](https://github.com/eclipse-zenoh/zenoh/blob/main/zenoh/examples/zenoh/z_eval.rs)
or
[Python](https://github.com/eclipse-zenoh/zenoh-python/blob/main/examples/zenoh/z_eval.py)).
.
-------------------------------
.
## **Configuration**
.
In its configuration part, the plugin supports those settings:
.
- **`http_port`** - int or string - required:
either a port number as an integer or a string, either a string with format
`":"`
.
-------------------------------
.
## **Troubleshooting**
.
### _Address already in use_
.
If in `zenohd` logs you see such error log at startup:
.
```raw
[2021-04-12T14:20:51Z ERROR zenoh_plugin_webserver] Unable to start http server
for REST : Os { code: 48, kind: AddrInUse, message: "Address already in use" }
```
.
It means another process is already using this port number that the webserver
plugin would like to use.
In such case, you have 2 solutions:
.
- stop the other process using this port
- make the webserver plugin to another port changing its `listener` option.
.
### _Permission denied_
.
If in `zenohd` logs you see such error log at startup:
.
```raw
[2021-04-12T13:55:10Z ERROR zenoh_plugin_webserver] Unable to start http server
for REST : Os { code: 13, kind: PermissionDenied, message: "Permission denied"
```
.
It probably means your OS (this usually happens on Linux) forbids the usage of
the configured port for non-root user (actually it usually restricts all ports
between 0 and 1024).
In such case, you have 2 solutions:
.
- run zenohd with root privileges (via `sudo`)
- use another changing he webserver plugin's `listener` option.
.
-------------------------------
.
## **How to build it**
.
> :warning: **WARNING** :warning: : Zenoh and its ecosystem are under active
development. When you build from git, make sure you also build from git any
other Zenoh repository you plan to use (e.g. binding, plugin, backend, etc.).
It may happen that some changes in git are not compatible with the most recent
packaged Zenoh release (e.g. deb, docker, pip). We put particular effort in
mantaining compatibility between the various git repositories in the Zenoh
project.
>
> :warning: **WARNING** :warning: : As Rust doesn't have a stable ABI, the
plugins should be
built with the exact same Rust version than `zenohd`, and using for `zenoh`
dependency the same version (or commit number) than 'zenohd'.
Otherwise, incompatibilities in memory mapping of shared types between `zenohd`
and the library can lead to a `"SIGSEV"` crash.
.
At first, install [Cargo and
Rust](https://doc.rust-lang.org/cargo/getting-started/installation.html). If
you already have the Rust toolchain installed, make sure it is up-to-date with:
.
```bash
rustup update
```
.
To know the Rust version you're `zenohd` has been built with, use the
`--version` option.
Example:
.
```bash
zenohd --version
The zenoh router v0.6.0-beta.1 built with rustc 1.64.0 (a55dd71d5 2022-09-19)
```
.
Here, `zenohd` has been built with the rustc version `1.64.0`.
Install and use this toolchain with the following command:
.
```bash
rustup default 1.64.0
```
.
And `zenohd` version corresponds to an un-released commit with id `1f20c86`.
Update the `zenoh` dependency in Cargo.lock with this command:
.
```bash
cargo update -p zenoh --precise 1f20c86
```
.
Then build the backend with:
.
```bash
cargo build --release -p zenoh-plugin-webserver
```