Package: zenoh-backend-filesystem
Version: 1.7.1
Architecture: armel
Maintainer: zenoh-dev@eclipse.org
Installed-Size: 11902
Depends: zenoh-plugin-storage-manager (=1.7.1)
Filename: 1.7.1/zenoh-backend-filesystem_1.7.1_armel.deb
Size: 3161038
MD5sum: 4b3a83b02cf76634fc5554ac7ea28282
SHA1: d6ce3a2e4cf5e946ed1d70ce6efc75a012143432
SHA256: 083f07b512532e49517ad377ad7504f64c23435476a9fed122d339fe8916c72d
Section: net
Priority: optional
Homepage: http://zenoh.io
Description: Backend for Zenoh using the file system
.
[](https://github.com/eclipse-zenoh/zenoh-backend-filesystem/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.
.
-------------------------------
.
# File system backend
.
In zenoh a backend is a storage technology (such as DBMS, time-series database,
file system...) alowing to store the
keys/values publications made via zenoh and return them on queries.
See the [zenoh
documentation](https://zenoh.io/docs/manual/abstractions/#storage) for more
details.
.
This backend relies on the host's file system to implement the storages.
Its library name (without OS specific prefix and extension) that zenoh will
rely on to find it and load it is **`zenoh_backend_fs`**.
.
:point_right: **Install latest release:** see [below](#how-to-install-it)
.
:point_right: **Build "main" branch:** see [below](#how-to-build-it)
.
-------------------------------
.
## **Examples of usage**
.
Prerequisites:
.
- You have a zenoh router (`zenohd`) installed, and the `zenoh_backend_fs`
library file is available in `~/.zenoh/lib`.
- Declare the `ZENOH_BACKEND_FS_ROOT` environment variable to the directory
where you want the files to be stored (or exposed from).
If you don't declare it, the `~/.zenoh/zenoh_backend_fs` directory will be
used.
.
You can setup storages either at zenoh router startup via a configuration file,
either at runtime via the zenoh admin space, using for instance the REST API.
.
### **Setup via a JSON5 configuration file**
.
- Create a `zenoh.json5` configuration file containing:
.
```json5
{
plugins: {
// configuration of "storage-manager" plugin:
storage_manager: {
volumes: {
// configuration of a "fs" volume (the "zenoh_backend_fs" backend
library will be loaded at startup)
fs: {},
},
storages: {
// configuration of a "demo" storage using the "fs" volume
demo: {
// the key expression this storage will subscribes to
key_expr: "demo/example/**",
// this prefix will be stripped from the received key when
converting to file path
// this argument is optional.
strip_prefix: "demo/example",
volume: {
id: "fs",
// the key/values will be stored as files within this directory
(relative to ${ZENOH_BACKEND_FS_ROOT})
dir: "example"
}
}
}
},
// Optionally, add the REST plugin
rest: { http_port: 8000 }
}
}
```
.
- Run the zenoh router with:
`zenohd -c zenoh.json5`
.
### **Setup at runtime via `curl` commands on the admin space**
.
- Run the zenoh router, with write permissions to its admin space and with the
REST plugin:
`zenohd --adminspace-permissions=rw --rest-http-port=8000`
- Add the "fs" backend (the "zenoh_backend_fs" library will be loaded):
`curl -X PUT -H 'content-type:application/json' -d '{}'
http://localhost:8000/@/local/router/config/plugins/storage_manager/volumes/fs`
- Add the "demo" storage using the "fs" backend:
`curl -X PUT -H 'content-type:application/json' -d
'{key_expr:"demo/example/**",strip_prefix:"demo/example", volume: {id: "fs",
dir:"example"}}'
http://localhost:8000/@/local/router/config/plugins/storage_manager/storages/demo`
.
### **Tests using the REST API**
.
Using `curl` to publish and query keys/values, you can:
.
```bash
# Put values that will be stored under ${ZENOH_BACKEND_FS_ROOT}/example
curl -X PUT -d "TEST-1" http://localhost:8000/demo/example/test-1
curl -X PUT -d "B" http://localhost:8000/demo/example/a/b
.
# Retrive the values
curl http://localhost:8000/demo/example/**
```
.
.
-------------------------------
.
## Configuration
.
### Extra configuration for filesystem-backed volumes
.
Volumes using the `fs` backend don't need any extra configuration at the volume
level. Any volume can use the `fs` backend by specifying the value `"fs"` for
the `backend` configuration key. A volume named `fs` will automatically be
backed by the `fs` backend if no other backend is specified.
.
-------------------------------
.
### Storage-level configuration for filesystem-backed volumes
.
Storages relying on a `fs` backed volume must/can specify additional
configuration specific to that volume, as shown in the example
[above](#setup-via-a-json5-configuration-file):
.
- `dir` (**required**, string) : The directory that will be used to store data.
.
- `read_only` (optional, boolean) : the storage will only answer to GET
queries. It will not accept any PUT or DELETE message, and won't write any
file. `false` by default.
.
- `on_closure` (optional, string) : the strategy to use when the Storage is
removed. There are 2 options:
- `"do_nothing"`: the storage's directory remains untouched (this is the
default behaviour)
- `"delete_all"`: the storage's directory is deleted with all its content.
.
- `follow_links` (optional, boolean) : If set to `true` the storage will follow
the symbolic links. The default value is `false`.
.
- `keep_mime_types` (optional, boolean) : When replying to a GET query with a
file for which the zenoh encoding is not known, the storage guess its mime-type
according to the file extension. If the mime-type doesn't correspond to a
supported zenoh encoding, this option will drive the returned value:
- `true` (default value): a [Custom
value](https://docs.rs/zenoh/latest/zenoh/enum.Value.html#variant.Custom)
is returned with the description set to the mime-type.
- `false`: a [Raw
value](https://docs.rs/zenoh/latest/zenoh/enum.Value.html#variant.Raw) with
APP_OCTET_STREAM encoding is returned.
.
-------------------------------
.
## **Behaviour of the backend**
.
### Mapping to file system
.
Each **storage** will map to a directory with path:
`${ZENOH_BACKEND_FS_ROOT}/`, where:
.
- `${ZENOH_BACKEND_FS_ROOT}` is an environment variable that could be specified
before zenoh router startup.
If this variable is not specified `${ZENOH_HOME}/zenoh_backend_fs` will be
used
(where the default value of `${ZENOH_HOME}` is `~/.zenoh`).
- `` is the `"dir"` property specified at storage creation.
ch zenoh **key/value** put into the storage will map to a file within the
storage's directory where:
- the file path will be `${ZENOH_BACKEND_FS_ROOT}//`,
where ``
will be the zenoh key, stripped from the `"strip_prefix"` property specified
at storage creation.
- the content of the file will be the value written as a RawValue. I.e. the
same bytes buffer that has been
transported by zenoh. For UTF-8 compatible formats (StringUTF8, JSon,
Integer, Float...) it means the file
will be readable as a text format.
- the encoding and the timestamp of the key/value will be stored in a RocksDB
database stored in the storage directory.
.
### Behaviour on deletion
.
On deletion of a key, the corresponding file is removed. An entry with deletion
timestamp is inserted in the
RocksDB database (to avoid re-insertion of points with an older timestamp in
case of un-ordered messages).
At regular interval, a task cleans-up the RocksDB database from entries with
old timestamps that don't have a
corresponding existing file.
.
### Behaviour on GET
.
On GET operations, the storage searches for matching and existing files, and
return their raw content as a reply.
For each, the encoding and timestamp are retrieved from the RocksDB database.
But if no entry is found in the
database for a file (e.g. for files created without zenoh), the encoding is
deduced from the file's extension
(using [mime_guess](https://crates.io/crates/mime_guess)), and the timestamp is
deduced from the file's
modification time.
.
-------------------------------
.
## How to install it
.
To install the latest release of this backend library, you can do as follows:
.
### Manual installation (all platforms)
.
All release packages can be downloaded from:
.
-
[https://download.eclipse.org/zenoh/zenoh-backend-filesystem/latest/](https://download.eclipse.org/zenoh/zenoh-backend-filesystem/latest/)
.
Each subdirectory has the name of the Rust target. See the platforms each
target corresponds to on
[https://doc.rust-lang.org/stable/rustc/platform-support.html](https://doc.rust-lang.org/stable/rustc/platform-support.html)
.
Choose your platform and download the `.zip` file.
Unzip it in the same directory than `zenohd` or to any directory where it can
find the backend library (e.g. /usr/lib or ~/.zenoh/lib)
.
### Linux Debian
.
Add Eclipse Zenoh private repository to the sources list, and install the
`zenoh-backend-filesystem` package:
.
```bash
echo "deb [trusted=yes] https://download.eclipse.org/zenoh/debian-repo/ /" |
sudo tee -a /etc/apt/sources.list.d/zenoh.list > /dev/null
sudo apt update
sudo apt install zenoh-backend-filesystem
```
.
-------------------------------
.
## How to build it
.
At first, install [Clang](https://clang.llvm.org/) and [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
```
.
> :warning: **WARNING** :warning: : As Rust doesn't have a stable ABI, the
backend library 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.
.
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 --all-targets
```
Package: zenoh-backend-filesystem
Version: 1.7.1
Architecture: arm64
Maintainer: zenoh-dev@eclipse.org
Installed-Size: 12487
Depends: zenoh-plugin-storage-manager (=1.7.1)
Filename: 1.7.1/zenoh-backend-filesystem_1.7.1_arm64.deb
Size: 3187786
MD5sum: 5c4fbcac4e086ae30a341a5b306a6507
SHA1: 3bab24121226a1b74a796a7c187474a1645990a0
SHA256: 677aed00c7ad1cb4c5b0775c5f11a011207afe6e70878923402621f6e87121a5
Section: net
Priority: optional
Homepage: http://zenoh.io
Description: Backend for Zenoh using the file system
.
[](https://github.com/eclipse-zenoh/zenoh-backend-filesystem/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.
.
-------------------------------
.
# File system backend
.
In zenoh a backend is a storage technology (such as DBMS, time-series database,
file system...) alowing to store the
keys/values publications made via zenoh and return them on queries.
See the [zenoh
documentation](https://zenoh.io/docs/manual/abstractions/#storage) for more
details.
.
This backend relies on the host's file system to implement the storages.
Its library name (without OS specific prefix and extension) that zenoh will
rely on to find it and load it is **`zenoh_backend_fs`**.
.
:point_right: **Install latest release:** see [below](#how-to-install-it)
.
:point_right: **Build "main" branch:** see [below](#how-to-build-it)
.
-------------------------------
.
## **Examples of usage**
.
Prerequisites:
.
- You have a zenoh router (`zenohd`) installed, and the `zenoh_backend_fs`
library file is available in `~/.zenoh/lib`.
- Declare the `ZENOH_BACKEND_FS_ROOT` environment variable to the directory
where you want the files to be stored (or exposed from).
If you don't declare it, the `~/.zenoh/zenoh_backend_fs` directory will be
used.
.
You can setup storages either at zenoh router startup via a configuration file,
either at runtime via the zenoh admin space, using for instance the REST API.
.
### **Setup via a JSON5 configuration file**
.
- Create a `zenoh.json5` configuration file containing:
.
```json5
{
plugins: {
// configuration of "storage-manager" plugin:
storage_manager: {
volumes: {
// configuration of a "fs" volume (the "zenoh_backend_fs" backend
library will be loaded at startup)
fs: {},
},
storages: {
// configuration of a "demo" storage using the "fs" volume
demo: {
// the key expression this storage will subscribes to
key_expr: "demo/example/**",
// this prefix will be stripped from the received key when
converting to file path
// this argument is optional.
strip_prefix: "demo/example",
volume: {
id: "fs",
// the key/values will be stored as files within this directory
(relative to ${ZENOH_BACKEND_FS_ROOT})
dir: "example"
}
}
}
},
// Optionally, add the REST plugin
rest: { http_port: 8000 }
}
}
```
.
- Run the zenoh router with:
`zenohd -c zenoh.json5`
.
### **Setup at runtime via `curl` commands on the admin space**
.
- Run the zenoh router, with write permissions to its admin space and with the
REST plugin:
`zenohd --adminspace-permissions=rw --rest-http-port=8000`
- Add the "fs" backend (the "zenoh_backend_fs" library will be loaded):
`curl -X PUT -H 'content-type:application/json' -d '{}'
http://localhost:8000/@/local/router/config/plugins/storage_manager/volumes/fs`
- Add the "demo" storage using the "fs" backend:
`curl -X PUT -H 'content-type:application/json' -d
'{key_expr:"demo/example/**",strip_prefix:"demo/example", volume: {id: "fs",
dir:"example"}}'
http://localhost:8000/@/local/router/config/plugins/storage_manager/storages/demo`
.
### **Tests using the REST API**
.
Using `curl` to publish and query keys/values, you can:
.
```bash
# Put values that will be stored under ${ZENOH_BACKEND_FS_ROOT}/example
curl -X PUT -d "TEST-1" http://localhost:8000/demo/example/test-1
curl -X PUT -d "B" http://localhost:8000/demo/example/a/b
.
# Retrive the values
curl http://localhost:8000/demo/example/**
```
.
.
-------------------------------
.
## Configuration
.
### Extra configuration for filesystem-backed volumes
.
Volumes using the `fs` backend don't need any extra configuration at the volume
level. Any volume can use the `fs` backend by specifying the value `"fs"` for
the `backend` configuration key. A volume named `fs` will automatically be
backed by the `fs` backend if no other backend is specified.
.
-------------------------------
.
### Storage-level configuration for filesystem-backed volumes
.
Storages relying on a `fs` backed volume must/can specify additional
configuration specific to that volume, as shown in the example
[above](#setup-via-a-json5-configuration-file):
.
- `dir` (**required**, string) : The directory that will be used to store data.
.
- `read_only` (optional, boolean) : the storage will only answer to GET
queries. It will not accept any PUT or DELETE message, and won't write any
file. `false` by default.
.
- `on_closure` (optional, string) : the strategy to use when the Storage is
removed. There are 2 options:
- `"do_nothing"`: the storage's directory remains untouched (this is the
default behaviour)
- `"delete_all"`: the storage's directory is deleted with all its content.
.
- `follow_links` (optional, boolean) : If set to `true` the storage will follow
the symbolic links. The default value is `false`.
.
- `keep_mime_types` (optional, boolean) : When replying to a GET query with a
file for which the zenoh encoding is not known, the storage guess its mime-type
according to the file extension. If the mime-type doesn't correspond to a
supported zenoh encoding, this option will drive the returned value:
- `true` (default value): a [Custom
value](https://docs.rs/zenoh/latest/zenoh/enum.Value.html#variant.Custom)
is returned with the description set to the mime-type.
- `false`: a [Raw
value](https://docs.rs/zenoh/latest/zenoh/enum.Value.html#variant.Raw) with
APP_OCTET_STREAM encoding is returned.
.
-------------------------------
.
## **Behaviour of the backend**
.
### Mapping to file system
.
Each **storage** will map to a directory with path:
`${ZENOH_BACKEND_FS_ROOT}/`, where:
.
- `${ZENOH_BACKEND_FS_ROOT}` is an environment variable that could be specified
before zenoh router startup.
If this variable is not specified `${ZENOH_HOME}/zenoh_backend_fs` will be
used
(where the default value of `${ZENOH_HOME}` is `~/.zenoh`).
- `` is the `"dir"` property specified at storage creation.
ch zenoh **key/value** put into the storage will map to a file within the
storage's directory where:
- the file path will be `${ZENOH_BACKEND_FS_ROOT}//`,
where ``
will be the zenoh key, stripped from the `"strip_prefix"` property specified
at storage creation.
- the content of the file will be the value written as a RawValue. I.e. the
same bytes buffer that has been
transported by zenoh. For UTF-8 compatible formats (StringUTF8, JSon,
Integer, Float...) it means the file
will be readable as a text format.
- the encoding and the timestamp of the key/value will be stored in a RocksDB
database stored in the storage directory.
.
### Behaviour on deletion
.
On deletion of a key, the corresponding file is removed. An entry with deletion
timestamp is inserted in the
RocksDB database (to avoid re-insertion of points with an older timestamp in
case of un-ordered messages).
At regular interval, a task cleans-up the RocksDB database from entries with
old timestamps that don't have a
corresponding existing file.
.
### Behaviour on GET
.
On GET operations, the storage searches for matching and existing files, and
return their raw content as a reply.
For each, the encoding and timestamp are retrieved from the RocksDB database.
But if no entry is found in the
database for a file (e.g. for files created without zenoh), the encoding is
deduced from the file's extension
(using [mime_guess](https://crates.io/crates/mime_guess)), and the timestamp is
deduced from the file's
modification time.
.
-------------------------------
.
## How to install it
.
To install the latest release of this backend library, you can do as follows:
.
### Manual installation (all platforms)
.
All release packages can be downloaded from:
.
-
[https://download.eclipse.org/zenoh/zenoh-backend-filesystem/latest/](https://download.eclipse.org/zenoh/zenoh-backend-filesystem/latest/)
.
Each subdirectory has the name of the Rust target. See the platforms each
target corresponds to on
[https://doc.rust-lang.org/stable/rustc/platform-support.html](https://doc.rust-lang.org/stable/rustc/platform-support.html)
.
Choose your platform and download the `.zip` file.
Unzip it in the same directory than `zenohd` or to any directory where it can
find the backend library (e.g. /usr/lib or ~/.zenoh/lib)
.
### Linux Debian
.
Add Eclipse Zenoh private repository to the sources list, and install the
`zenoh-backend-filesystem` package:
.
```bash
echo "deb [trusted=yes] https://download.eclipse.org/zenoh/debian-repo/ /" |
sudo tee -a /etc/apt/sources.list.d/zenoh.list > /dev/null
sudo apt update
sudo apt install zenoh-backend-filesystem
```
.
-------------------------------
.
## How to build it
.
At first, install [Clang](https://clang.llvm.org/) and [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
```
.
> :warning: **WARNING** :warning: : As Rust doesn't have a stable ABI, the
backend library 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.
.
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 --all-targets
```
Package: zenoh-backend-filesystem
Version: 1.7.1
Architecture: armhf
Maintainer: zenoh-dev@eclipse.org
Installed-Size: 9865
Depends: zenoh-plugin-storage-manager (=1.7.1)
Filename: 1.7.1/zenoh-backend-filesystem_1.7.1_armhf.deb
Size: 3273314
MD5sum: ff9bc02dbe031099494c0337d47fabf9
SHA1: 7374db774e8c1029e0fc219c9a3ba54662ad5555
SHA256: 6081da4ce4e8c96112b675ab15c01a6abaa9f116cc5c5e69891358dab2537a32
Section: net
Priority: optional
Homepage: http://zenoh.io
Description: Backend for Zenoh using the file system
.
[](https://github.com/eclipse-zenoh/zenoh-backend-filesystem/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.
.
-------------------------------
.
# File system backend
.
In zenoh a backend is a storage technology (such as DBMS, time-series database,
file system...) alowing to store the
keys/values publications made via zenoh and return them on queries.
See the [zenoh
documentation](https://zenoh.io/docs/manual/abstractions/#storage) for more
details.
.
This backend relies on the host's file system to implement the storages.
Its library name (without OS specific prefix and extension) that zenoh will
rely on to find it and load it is **`zenoh_backend_fs`**.
.
:point_right: **Install latest release:** see [below](#how-to-install-it)
.
:point_right: **Build "main" branch:** see [below](#how-to-build-it)
.
-------------------------------
.
## **Examples of usage**
.
Prerequisites:
.
- You have a zenoh router (`zenohd`) installed, and the `zenoh_backend_fs`
library file is available in `~/.zenoh/lib`.
- Declare the `ZENOH_BACKEND_FS_ROOT` environment variable to the directory
where you want the files to be stored (or exposed from).
If you don't declare it, the `~/.zenoh/zenoh_backend_fs` directory will be
used.
.
You can setup storages either at zenoh router startup via a configuration file,
either at runtime via the zenoh admin space, using for instance the REST API.
.
### **Setup via a JSON5 configuration file**
.
- Create a `zenoh.json5` configuration file containing:
.
```json5
{
plugins: {
// configuration of "storage-manager" plugin:
storage_manager: {
volumes: {
// configuration of a "fs" volume (the "zenoh_backend_fs" backend
library will be loaded at startup)
fs: {},
},
storages: {
// configuration of a "demo" storage using the "fs" volume
demo: {
// the key expression this storage will subscribes to
key_expr: "demo/example/**",
// this prefix will be stripped from the received key when
converting to file path
// this argument is optional.
strip_prefix: "demo/example",
volume: {
id: "fs",
// the key/values will be stored as files within this directory
(relative to ${ZENOH_BACKEND_FS_ROOT})
dir: "example"
}
}
}
},
// Optionally, add the REST plugin
rest: { http_port: 8000 }
}
}
```
.
- Run the zenoh router with:
`zenohd -c zenoh.json5`
.
### **Setup at runtime via `curl` commands on the admin space**
.
- Run the zenoh router, with write permissions to its admin space and with the
REST plugin:
`zenohd --adminspace-permissions=rw --rest-http-port=8000`
- Add the "fs" backend (the "zenoh_backend_fs" library will be loaded):
`curl -X PUT -H 'content-type:application/json' -d '{}'
http://localhost:8000/@/local/router/config/plugins/storage_manager/volumes/fs`
- Add the "demo" storage using the "fs" backend:
`curl -X PUT -H 'content-type:application/json' -d
'{key_expr:"demo/example/**",strip_prefix:"demo/example", volume: {id: "fs",
dir:"example"}}'
http://localhost:8000/@/local/router/config/plugins/storage_manager/storages/demo`
.
### **Tests using the REST API**
.
Using `curl` to publish and query keys/values, you can:
.
```bash
# Put values that will be stored under ${ZENOH_BACKEND_FS_ROOT}/example
curl -X PUT -d "TEST-1" http://localhost:8000/demo/example/test-1
curl -X PUT -d "B" http://localhost:8000/demo/example/a/b
.
# Retrive the values
curl http://localhost:8000/demo/example/**
```
.
.
-------------------------------
.
## Configuration
.
### Extra configuration for filesystem-backed volumes
.
Volumes using the `fs` backend don't need any extra configuration at the volume
level. Any volume can use the `fs` backend by specifying the value `"fs"` for
the `backend` configuration key. A volume named `fs` will automatically be
backed by the `fs` backend if no other backend is specified.
.
-------------------------------
.
### Storage-level configuration for filesystem-backed volumes
.
Storages relying on a `fs` backed volume must/can specify additional
configuration specific to that volume, as shown in the example
[above](#setup-via-a-json5-configuration-file):
.
- `dir` (**required**, string) : The directory that will be used to store data.
.
- `read_only` (optional, boolean) : the storage will only answer to GET
queries. It will not accept any PUT or DELETE message, and won't write any
file. `false` by default.
.
- `on_closure` (optional, string) : the strategy to use when the Storage is
removed. There are 2 options:
- `"do_nothing"`: the storage's directory remains untouched (this is the
default behaviour)
- `"delete_all"`: the storage's directory is deleted with all its content.
.
- `follow_links` (optional, boolean) : If set to `true` the storage will follow
the symbolic links. The default value is `false`.
.
- `keep_mime_types` (optional, boolean) : When replying to a GET query with a
file for which the zenoh encoding is not known, the storage guess its mime-type
according to the file extension. If the mime-type doesn't correspond to a
supported zenoh encoding, this option will drive the returned value:
- `true` (default value): a [Custom
value](https://docs.rs/zenoh/latest/zenoh/enum.Value.html#variant.Custom)
is returned with the description set to the mime-type.
- `false`: a [Raw
value](https://docs.rs/zenoh/latest/zenoh/enum.Value.html#variant.Raw) with
APP_OCTET_STREAM encoding is returned.
.
-------------------------------
.
## **Behaviour of the backend**
.
### Mapping to file system
.
Each **storage** will map to a directory with path:
`${ZENOH_BACKEND_FS_ROOT}/`, where:
.
- `${ZENOH_BACKEND_FS_ROOT}` is an environment variable that could be specified
before zenoh router startup.
If this variable is not specified `${ZENOH_HOME}/zenoh_backend_fs` will be
used
(where the default value of `${ZENOH_HOME}` is `~/.zenoh`).
- `` is the `"dir"` property specified at storage creation.
ch zenoh **key/value** put into the storage will map to a file within the
storage's directory where:
- the file path will be `${ZENOH_BACKEND_FS_ROOT}//`,
where ``
will be the zenoh key, stripped from the `"strip_prefix"` property specified
at storage creation.
- the content of the file will be the value written as a RawValue. I.e. the
same bytes buffer that has been
transported by zenoh. For UTF-8 compatible formats (StringUTF8, JSon,
Integer, Float...) it means the file
will be readable as a text format.
- the encoding and the timestamp of the key/value will be stored in a RocksDB
database stored in the storage directory.
.
### Behaviour on deletion
.
On deletion of a key, the corresponding file is removed. An entry with deletion
timestamp is inserted in the
RocksDB database (to avoid re-insertion of points with an older timestamp in
case of un-ordered messages).
At regular interval, a task cleans-up the RocksDB database from entries with
old timestamps that don't have a
corresponding existing file.
.
### Behaviour on GET
.
On GET operations, the storage searches for matching and existing files, and
return their raw content as a reply.
For each, the encoding and timestamp are retrieved from the RocksDB database.
But if no entry is found in the
database for a file (e.g. for files created without zenoh), the encoding is
deduced from the file's extension
(using [mime_guess](https://crates.io/crates/mime_guess)), and the timestamp is
deduced from the file's
modification time.
.
-------------------------------
.
## How to install it
.
To install the latest release of this backend library, you can do as follows:
.
### Manual installation (all platforms)
.
All release packages can be downloaded from:
.
-
[https://download.eclipse.org/zenoh/zenoh-backend-filesystem/latest/](https://download.eclipse.org/zenoh/zenoh-backend-filesystem/latest/)
.
Each subdirectory has the name of the Rust target. See the platforms each
target corresponds to on
[https://doc.rust-lang.org/stable/rustc/platform-support.html](https://doc.rust-lang.org/stable/rustc/platform-support.html)
.
Choose your platform and download the `.zip` file.
Unzip it in the same directory than `zenohd` or to any directory where it can
find the backend library (e.g. /usr/lib or ~/.zenoh/lib)
.
### Linux Debian
.
Add Eclipse Zenoh private repository to the sources list, and install the
`zenoh-backend-filesystem` package:
.
```bash
echo "deb [trusted=yes] https://download.eclipse.org/zenoh/debian-repo/ /" |
sudo tee -a /etc/apt/sources.list.d/zenoh.list > /dev/null
sudo apt update
sudo apt install zenoh-backend-filesystem
```
.
-------------------------------
.
## How to build it
.
At first, install [Clang](https://clang.llvm.org/) and [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
```
.
> :warning: **WARNING** :warning: : As Rust doesn't have a stable ABI, the
backend library 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.
.
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 --all-targets
```
Package: zenoh-backend-filesystem
Version: 1.7.1
Architecture: amd64
Maintainer: zenoh-dev@eclipse.org
Installed-Size: 13811
Depends: zenoh-plugin-storage-manager (=1.7.1)
Filename: 1.7.1/zenoh-backend-filesystem_1.7.1_amd64.deb
Size: 3693982
MD5sum: 991ed3e850b6e30c35672892ac3e9679
SHA1: 57300c02d20020a624a2a581532545eea214a4f8
SHA256: 4b4644d58712e8b339708058291d75f719f03f554d42dba2af158f35c5937a91
Section: net
Priority: optional
Homepage: http://zenoh.io
Description: Backend for Zenoh using the file system
.
[](https://github.com/eclipse-zenoh/zenoh-backend-filesystem/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.
.
-------------------------------
.
# File system backend
.
In zenoh a backend is a storage technology (such as DBMS, time-series database,
file system...) alowing to store the
keys/values publications made via zenoh and return them on queries.
See the [zenoh
documentation](https://zenoh.io/docs/manual/abstractions/#storage) for more
details.
.
This backend relies on the host's file system to implement the storages.
Its library name (without OS specific prefix and extension) that zenoh will
rely on to find it and load it is **`zenoh_backend_fs`**.
.
:point_right: **Install latest release:** see [below](#how-to-install-it)
.
:point_right: **Build "main" branch:** see [below](#how-to-build-it)
.
-------------------------------
.
## **Examples of usage**
.
Prerequisites:
.
- You have a zenoh router (`zenohd`) installed, and the `zenoh_backend_fs`
library file is available in `~/.zenoh/lib`.
- Declare the `ZENOH_BACKEND_FS_ROOT` environment variable to the directory
where you want the files to be stored (or exposed from).
If you don't declare it, the `~/.zenoh/zenoh_backend_fs` directory will be
used.
.
You can setup storages either at zenoh router startup via a configuration file,
either at runtime via the zenoh admin space, using for instance the REST API.
.
### **Setup via a JSON5 configuration file**
.
- Create a `zenoh.json5` configuration file containing:
.
```json5
{
plugins: {
// configuration of "storage-manager" plugin:
storage_manager: {
volumes: {
// configuration of a "fs" volume (the "zenoh_backend_fs" backend
library will be loaded at startup)
fs: {},
},
storages: {
// configuration of a "demo" storage using the "fs" volume
demo: {
// the key expression this storage will subscribes to
key_expr: "demo/example/**",
// this prefix will be stripped from the received key when
converting to file path
// this argument is optional.
strip_prefix: "demo/example",
volume: {
id: "fs",
// the key/values will be stored as files within this directory
(relative to ${ZENOH_BACKEND_FS_ROOT})
dir: "example"
}
}
}
},
// Optionally, add the REST plugin
rest: { http_port: 8000 }
}
}
```
.
- Run the zenoh router with:
`zenohd -c zenoh.json5`
.
### **Setup at runtime via `curl` commands on the admin space**
.
- Run the zenoh router, with write permissions to its admin space and with the
REST plugin:
`zenohd --adminspace-permissions=rw --rest-http-port=8000`
- Add the "fs" backend (the "zenoh_backend_fs" library will be loaded):
`curl -X PUT -H 'content-type:application/json' -d '{}'
http://localhost:8000/@/local/router/config/plugins/storage_manager/volumes/fs`
- Add the "demo" storage using the "fs" backend:
`curl -X PUT -H 'content-type:application/json' -d
'{key_expr:"demo/example/**",strip_prefix:"demo/example", volume: {id: "fs",
dir:"example"}}'
http://localhost:8000/@/local/router/config/plugins/storage_manager/storages/demo`
.
### **Tests using the REST API**
.
Using `curl` to publish and query keys/values, you can:
.
```bash
# Put values that will be stored under ${ZENOH_BACKEND_FS_ROOT}/example
curl -X PUT -d "TEST-1" http://localhost:8000/demo/example/test-1
curl -X PUT -d "B" http://localhost:8000/demo/example/a/b
.
# Retrive the values
curl http://localhost:8000/demo/example/**
```
.
.
-------------------------------
.
## Configuration
.
### Extra configuration for filesystem-backed volumes
.
Volumes using the `fs` backend don't need any extra configuration at the volume
level. Any volume can use the `fs` backend by specifying the value `"fs"` for
the `backend` configuration key. A volume named `fs` will automatically be
backed by the `fs` backend if no other backend is specified.
.
-------------------------------
.
### Storage-level configuration for filesystem-backed volumes
.
Storages relying on a `fs` backed volume must/can specify additional
configuration specific to that volume, as shown in the example
[above](#setup-via-a-json5-configuration-file):
.
- `dir` (**required**, string) : The directory that will be used to store data.
.
- `read_only` (optional, boolean) : the storage will only answer to GET
queries. It will not accept any PUT or DELETE message, and won't write any
file. `false` by default.
.
- `on_closure` (optional, string) : the strategy to use when the Storage is
removed. There are 2 options:
- `"do_nothing"`: the storage's directory remains untouched (this is the
default behaviour)
- `"delete_all"`: the storage's directory is deleted with all its content.
.
- `follow_links` (optional, boolean) : If set to `true` the storage will follow
the symbolic links. The default value is `false`.
.
- `keep_mime_types` (optional, boolean) : When replying to a GET query with a
file for which the zenoh encoding is not known, the storage guess its mime-type
according to the file extension. If the mime-type doesn't correspond to a
supported zenoh encoding, this option will drive the returned value:
- `true` (default value): a [Custom
value](https://docs.rs/zenoh/latest/zenoh/enum.Value.html#variant.Custom)
is returned with the description set to the mime-type.
- `false`: a [Raw
value](https://docs.rs/zenoh/latest/zenoh/enum.Value.html#variant.Raw) with
APP_OCTET_STREAM encoding is returned.
.
-------------------------------
.
## **Behaviour of the backend**
.
### Mapping to file system
.
Each **storage** will map to a directory with path:
`${ZENOH_BACKEND_FS_ROOT}/`, where:
.
- `${ZENOH_BACKEND_FS_ROOT}` is an environment variable that could be specified
before zenoh router startup.
If this variable is not specified `${ZENOH_HOME}/zenoh_backend_fs` will be
used
(where the default value of `${ZENOH_HOME}` is `~/.zenoh`).
- `` is the `"dir"` property specified at storage creation.
ch zenoh **key/value** put into the storage will map to a file within the
storage's directory where:
- the file path will be `${ZENOH_BACKEND_FS_ROOT}//`,
where ``
will be the zenoh key, stripped from the `"strip_prefix"` property specified
at storage creation.
- the content of the file will be the value written as a RawValue. I.e. the
same bytes buffer that has been
transported by zenoh. For UTF-8 compatible formats (StringUTF8, JSon,
Integer, Float...) it means the file
will be readable as a text format.
- the encoding and the timestamp of the key/value will be stored in a RocksDB
database stored in the storage directory.
.
### Behaviour on deletion
.
On deletion of a key, the corresponding file is removed. An entry with deletion
timestamp is inserted in the
RocksDB database (to avoid re-insertion of points with an older timestamp in
case of un-ordered messages).
At regular interval, a task cleans-up the RocksDB database from entries with
old timestamps that don't have a
corresponding existing file.
.
### Behaviour on GET
.
On GET operations, the storage searches for matching and existing files, and
return their raw content as a reply.
For each, the encoding and timestamp are retrieved from the RocksDB database.
But if no entry is found in the
database for a file (e.g. for files created without zenoh), the encoding is
deduced from the file's extension
(using [mime_guess](https://crates.io/crates/mime_guess)), and the timestamp is
deduced from the file's
modification time.
.
-------------------------------
.
## How to install it
.
To install the latest release of this backend library, you can do as follows:
.
### Manual installation (all platforms)
.
All release packages can be downloaded from:
.
-
[https://download.eclipse.org/zenoh/zenoh-backend-filesystem/latest/](https://download.eclipse.org/zenoh/zenoh-backend-filesystem/latest/)
.
Each subdirectory has the name of the Rust target. See the platforms each
target corresponds to on
[https://doc.rust-lang.org/stable/rustc/platform-support.html](https://doc.rust-lang.org/stable/rustc/platform-support.html)
.
Choose your platform and download the `.zip` file.
Unzip it in the same directory than `zenohd` or to any directory where it can
find the backend library (e.g. /usr/lib or ~/.zenoh/lib)
.
### Linux Debian
.
Add Eclipse Zenoh private repository to the sources list, and install the
`zenoh-backend-filesystem` package:
.
```bash
echo "deb [trusted=yes] https://download.eclipse.org/zenoh/debian-repo/ /" |
sudo tee -a /etc/apt/sources.list.d/zenoh.list > /dev/null
sudo apt update
sudo apt install zenoh-backend-filesystem
```
.
-------------------------------
.
## How to build it
.
At first, install [Clang](https://clang.llvm.org/) and [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
```
.
> :warning: **WARNING** :warning: : As Rust doesn't have a stable ABI, the
backend library 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.
.
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 --all-targets
```