Package: zenoh-backend-rocksdb
Version: 1.0.3
Architecture: arm64
Maintainer: zenoh-dev@eclipse.org
Installed-Size: 17493
Depends: zenoh-plugin-storage-manager (=1.0.3)
Filename: 1.0.3/zenoh-backend-rocksdb_1.0.3_arm64.deb
Size: 3887904
MD5sum: d1a4f57e631ff23e11adceeee71c5a77
SHA1: 81605d364ba647a8783dca34662782a7b499dd66
SHA256: 78523043efa6b14611271318da71197bdf0b57b0917f4e99884872fe93716885
Section: net
Priority: optional
Homepage: http://zenoh.io
Description: Backend for Zenoh using RocksDB
.
[](https://github.com/eclipse-zenoh/zenoh-backend-rocksdb/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.
.
-------------------------------
# RocksDB 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](http://zenoh.io/docs/manual/backends/) for more
details.
.
This backend relies on [RocksDB](https://rocksdb.org/) 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_rocksdb`**.
.
: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_rocksdb` library file is available in `~/.zenoh/lib`.
- Declare the `ZENOH_BACKEND_ROCKSDB_ROOT` environment variable to the
directory where you want the RocksDB databases
to be stored. If you don't declare it, the `~/.zenoh/zenoh_backend_rocksdb`
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 "storages" plugin:
storage_manager: {
volumes: {
// configuration of a "rocksdb" volume (the "zenoh_backend_rocksdb"
backend library will be loaded at startup)
rocksdb: {}
},
storages: {
// configuration of a "demo" storage using the "rocksdb" 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 database key.
// i.e.: "demo/example/a/b" will be stored as "a/b"
strip_prefix: "demo/example",
volume: {
id: "rocksdb",
// the RocksDB database will be stored in this directory
(relative to ${ZENOH_BACKEND_ROCKSDB_ROOT})
dir: "example",
// create the RocksDB database if not already existing
create_db: true
}
}
}
},
// Optionally, add the REST plugin
rest: { http_port: 8000 }
}
}
```
- Run the zenoh router with:
`zenohd -c zenoh.json5`
.
### **Setup at runtime via `curl` commands on the admin space**
.
- Run the zenoh router, with write permissions to its admin space:
`zenohd --adminspace-permissions rw`
- Add the "rocksdb" backend (the "zenoh_backend_rocksdb" library will be
loaded):
`curl -X PUT -H 'content-type:application/json' -d '{}'
http://localhost:8000/@/router/local/config/plugins/storage_manager/volumes/rocksdb`
- Add the "demo" storage using the "rocksdb" backend:
`curl -X PUT -H 'content-type:application/json' -d
'{key_expr:"demo/example/**",strip_prefix:"demo/example",volume: {id:
"rocksdb",dir: "example",create_db: true}}'
http://localhost:8000/@/router/local/config/plugins/storage_manager/storages/demo`
.
### **Tests using the REST API**
.
Using `curl` to publish and query keys/values, you can:
```bash
# Put values that will be stored in the RocksDB database
curl -X PUT -d "TEST-1" http://localhost:8000/demo/example/test-1
curl -X PUT -d "B" http://localhost:8000/demo/example/a/b
.
# Retrive the values
curl http://localhost:8000/demo/example/**
```
.
-------------------------------
## Volume-specific storage configuration
Storages relying on a RocksDB-backed volume must specify some additional
configuration as shown [above](#setup-via-a-json5-configuration-file):
- **`"dir"`** (**required**, string) : The name of directory where the RocksDB
database is stored.
The absolute path will be `${ZENOH_BACKEND_ROCKSDB_ROOT}/`.
.
- **`"create_db"`** (optional, boolean) : create the RocksDB database if not
already existing. Not set by default.
*(the value doesn't matter, only the property existence is checked)*
.
- **`"read_only"`** (optional, boolean) : the storage will only answer to GET
queries. It will not accept any PUT or DELETE message, and won't put anything
in RocksDB database. Not set by default. *(the value doesn't matter, only the
property existence is checked)*
.
- **`"on_closure"`** (optional, string) : the strategy to use when the Storage
is removed. There are 2 options:
- *unset*: the database remains untouched (this is the default behaviour)
- `"destroy_db"`: the database is destroyed (i.e. removed)
.
-------------------------------
## **Behaviour of the backend**
.
### Mapping to RocksDB database
Each **storage** will map to a RocksDB database stored in directory:
`${ZENOH_BACKEND_ROCKSDB_ROOT}/`, where:
* `${ZENOH_BACKEND_ROCKSDB_ROOT}` is an environment variable that could be
specified before zenoh router startup.
If this variable is not specified `${ZENOH_HOME}/zenoh_backend_rocksdb`
will be used
(where the default value of `${ZENOH_HOME}` is `~/.zenoh`).
* `` is the `"dir"` property specified at storage creation.
Each zenoh **key/value** put into the storage will map to 2 **key/values** in
the database:
* For both, the database key is the zenoh key, stripped from the
`"strip_prefix"` property specified at storage creation.
* In the `"default"` [Column
Family](https://github.com/facebook/rocksdb/wiki/Column-Families) the key is
put with the zenoh encoded value as a value.
* In the `"data_info"` [Column
Family](https://github.com/facebook/rocksdb/wiki/Column-Families) the key is
put with a bytes buffer encoded in this order:
- the Timestamp encoded as: 8 bytes for the time + 16 bytes for the HLC
ID
- a "is deleted" flag encoded as a boolean on 1 byte
- the encoding prefix flag encoded as a ZInt (variable length)
- the encoding suffix encoded as a String (string length as a ZInt +
string bytes without ending `\0`)
.
### Behaviour on deletion
On deletion of a key, the corresponding key is removed from the `"default"`
Column Family. An entry with the
"deletion" flag set to true and the deletion timestamp is inserted in the
`"data-info"` Column Family
(to avoid re-insertion of points with an older timestamp in case of un-ordered
messages).
At regular interval, a task cleans-up the `"data-info"` Column Family from
entries with old timestamps and
the "deletion" flag set to true
.
### Behaviour on GET
On GET operations:
* if the selector is a unique key (i.e. not containing any `'*'`): the value
and its encoding and timestamp
for the corresponding key are directly retrieved from the 2 Column Families
using `get` RocksDB operation.
* if the selector is a key expression: the storage searches for matching
keys, leveraging RocksDB's [Prefix
Seek](https://github.com/facebook/rocksdb/wiki/Prefix-Seek) if possible to
minimize the number of entries to check.
.
-------------------------------
## 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-rocksdb/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
.
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-rocksdb` 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-rocksdb
```
.
-------------------------------
## 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.
.
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
```
Vcs-Browser: https://github.com/eclipse-zenoh/zenoh-backend-rocksdb
Vcs-Git: https://github.com/eclipse-zenoh/zenoh-backend-rocksdb
Package: zenoh-backend-rocksdb
Version: 1.0.3
Architecture: amd64
Maintainer: zenoh-dev@eclipse.org
Installed-Size: 19388
Depends: zenoh-plugin-storage-manager (=1.0.3)
Filename: 1.0.3/zenoh-backend-rocksdb_1.0.3_amd64.deb
Size: 4328224
MD5sum: b692e41e11ba8198088462accb4423ba
SHA1: 77694f5f58985db9ec8be98bfe9c01f2460d568b
SHA256: 56c644a790df7eb97933694a2ac4286e6413a82621b7d8090cd17ec8b8d45124
Section: net
Priority: optional
Homepage: http://zenoh.io
Description: Backend for Zenoh using RocksDB
.
[](https://github.com/eclipse-zenoh/zenoh-backend-rocksdb/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.
.
-------------------------------
# RocksDB 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](http://zenoh.io/docs/manual/backends/) for more
details.
.
This backend relies on [RocksDB](https://rocksdb.org/) 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_rocksdb`**.
.
: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_rocksdb` library file is available in `~/.zenoh/lib`.
- Declare the `ZENOH_BACKEND_ROCKSDB_ROOT` environment variable to the
directory where you want the RocksDB databases
to be stored. If you don't declare it, the `~/.zenoh/zenoh_backend_rocksdb`
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 "storages" plugin:
storage_manager: {
volumes: {
// configuration of a "rocksdb" volume (the "zenoh_backend_rocksdb"
backend library will be loaded at startup)
rocksdb: {}
},
storages: {
// configuration of a "demo" storage using the "rocksdb" 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 database key.
// i.e.: "demo/example/a/b" will be stored as "a/b"
strip_prefix: "demo/example",
volume: {
id: "rocksdb",
// the RocksDB database will be stored in this directory
(relative to ${ZENOH_BACKEND_ROCKSDB_ROOT})
dir: "example",
// create the RocksDB database if not already existing
create_db: true
}
}
}
},
// Optionally, add the REST plugin
rest: { http_port: 8000 }
}
}
```
- Run the zenoh router with:
`zenohd -c zenoh.json5`
.
### **Setup at runtime via `curl` commands on the admin space**
.
- Run the zenoh router, with write permissions to its admin space:
`zenohd --adminspace-permissions rw`
- Add the "rocksdb" backend (the "zenoh_backend_rocksdb" library will be
loaded):
`curl -X PUT -H 'content-type:application/json' -d '{}'
http://localhost:8000/@/router/local/config/plugins/storage_manager/volumes/rocksdb`
- Add the "demo" storage using the "rocksdb" backend:
`curl -X PUT -H 'content-type:application/json' -d
'{key_expr:"demo/example/**",strip_prefix:"demo/example",volume: {id:
"rocksdb",dir: "example",create_db: true}}'
http://localhost:8000/@/router/local/config/plugins/storage_manager/storages/demo`
.
### **Tests using the REST API**
.
Using `curl` to publish and query keys/values, you can:
```bash
# Put values that will be stored in the RocksDB database
curl -X PUT -d "TEST-1" http://localhost:8000/demo/example/test-1
curl -X PUT -d "B" http://localhost:8000/demo/example/a/b
.
# Retrive the values
curl http://localhost:8000/demo/example/**
```
.
-------------------------------
## Volume-specific storage configuration
Storages relying on a RocksDB-backed volume must specify some additional
configuration as shown [above](#setup-via-a-json5-configuration-file):
- **`"dir"`** (**required**, string) : The name of directory where the RocksDB
database is stored.
The absolute path will be `${ZENOH_BACKEND_ROCKSDB_ROOT}/`.
.
- **`"create_db"`** (optional, boolean) : create the RocksDB database if not
already existing. Not set by default.
*(the value doesn't matter, only the property existence is checked)*
.
- **`"read_only"`** (optional, boolean) : the storage will only answer to GET
queries. It will not accept any PUT or DELETE message, and won't put anything
in RocksDB database. Not set by default. *(the value doesn't matter, only the
property existence is checked)*
.
- **`"on_closure"`** (optional, string) : the strategy to use when the Storage
is removed. There are 2 options:
- *unset*: the database remains untouched (this is the default behaviour)
- `"destroy_db"`: the database is destroyed (i.e. removed)
.
-------------------------------
## **Behaviour of the backend**
.
### Mapping to RocksDB database
Each **storage** will map to a RocksDB database stored in directory:
`${ZENOH_BACKEND_ROCKSDB_ROOT}/`, where:
* `${ZENOH_BACKEND_ROCKSDB_ROOT}` is an environment variable that could be
specified before zenoh router startup.
If this variable is not specified `${ZENOH_HOME}/zenoh_backend_rocksdb`
will be used
(where the default value of `${ZENOH_HOME}` is `~/.zenoh`).
* `` is the `"dir"` property specified at storage creation.
Each zenoh **key/value** put into the storage will map to 2 **key/values** in
the database:
* For both, the database key is the zenoh key, stripped from the
`"strip_prefix"` property specified at storage creation.
* In the `"default"` [Column
Family](https://github.com/facebook/rocksdb/wiki/Column-Families) the key is
put with the zenoh encoded value as a value.
* In the `"data_info"` [Column
Family](https://github.com/facebook/rocksdb/wiki/Column-Families) the key is
put with a bytes buffer encoded in this order:
- the Timestamp encoded as: 8 bytes for the time + 16 bytes for the HLC
ID
- a "is deleted" flag encoded as a boolean on 1 byte
- the encoding prefix flag encoded as a ZInt (variable length)
- the encoding suffix encoded as a String (string length as a ZInt +
string bytes without ending `\0`)
.
### Behaviour on deletion
On deletion of a key, the corresponding key is removed from the `"default"`
Column Family. An entry with the
"deletion" flag set to true and the deletion timestamp is inserted in the
`"data-info"` Column Family
(to avoid re-insertion of points with an older timestamp in case of un-ordered
messages).
At regular interval, a task cleans-up the `"data-info"` Column Family from
entries with old timestamps and
the "deletion" flag set to true
.
### Behaviour on GET
On GET operations:
* if the selector is a unique key (i.e. not containing any `'*'`): the value
and its encoding and timestamp
for the corresponding key are directly retrieved from the 2 Column Families
using `get` RocksDB operation.
* if the selector is a key expression: the storage searches for matching
keys, leveraging RocksDB's [Prefix
Seek](https://github.com/facebook/rocksdb/wiki/Prefix-Seek) if possible to
minimize the number of entries to check.
.
-------------------------------
## 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-rocksdb/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
.
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-rocksdb` 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-rocksdb
```
.
-------------------------------
## 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.
.
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
```
Vcs-Browser: https://github.com/eclipse-zenoh/zenoh-backend-rocksdb
Vcs-Git: https://github.com/eclipse-zenoh/zenoh-backend-rocksdb
Package: zenoh-backend-rocksdb
Version: 1.0.3
Architecture: armhf
Maintainer: zenoh-dev@eclipse.org
Installed-Size: 13400
Depends: zenoh-plugin-storage-manager (=1.0.3)
Filename: 1.0.3/zenoh-backend-rocksdb_1.0.3_armhf.deb
Size: 3796748
MD5sum: 8405e7ac345c4dd703598a83de966136
SHA1: 3f078a41a89d894b26f4674696a786aa97f08a45
SHA256: 377a9c115c937bd3faa071226b866196efdd4bec7c6ef05e8bf40d39381e0b66
Section: net
Priority: optional
Homepage: http://zenoh.io
Description: Backend for Zenoh using RocksDB
.
[](https://github.com/eclipse-zenoh/zenoh-backend-rocksdb/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.
.
-------------------------------
# RocksDB 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](http://zenoh.io/docs/manual/backends/) for more
details.
.
This backend relies on [RocksDB](https://rocksdb.org/) 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_rocksdb`**.
.
: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_rocksdb` library file is available in `~/.zenoh/lib`.
- Declare the `ZENOH_BACKEND_ROCKSDB_ROOT` environment variable to the
directory where you want the RocksDB databases
to be stored. If you don't declare it, the `~/.zenoh/zenoh_backend_rocksdb`
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 "storages" plugin:
storage_manager: {
volumes: {
// configuration of a "rocksdb" volume (the "zenoh_backend_rocksdb"
backend library will be loaded at startup)
rocksdb: {}
},
storages: {
// configuration of a "demo" storage using the "rocksdb" 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 database key.
// i.e.: "demo/example/a/b" will be stored as "a/b"
strip_prefix: "demo/example",
volume: {
id: "rocksdb",
// the RocksDB database will be stored in this directory
(relative to ${ZENOH_BACKEND_ROCKSDB_ROOT})
dir: "example",
// create the RocksDB database if not already existing
create_db: true
}
}
}
},
// Optionally, add the REST plugin
rest: { http_port: 8000 }
}
}
```
- Run the zenoh router with:
`zenohd -c zenoh.json5`
.
### **Setup at runtime via `curl` commands on the admin space**
.
- Run the zenoh router, with write permissions to its admin space:
`zenohd --adminspace-permissions rw`
- Add the "rocksdb" backend (the "zenoh_backend_rocksdb" library will be
loaded):
`curl -X PUT -H 'content-type:application/json' -d '{}'
http://localhost:8000/@/router/local/config/plugins/storage_manager/volumes/rocksdb`
- Add the "demo" storage using the "rocksdb" backend:
`curl -X PUT -H 'content-type:application/json' -d
'{key_expr:"demo/example/**",strip_prefix:"demo/example",volume: {id:
"rocksdb",dir: "example",create_db: true}}'
http://localhost:8000/@/router/local/config/plugins/storage_manager/storages/demo`
.
### **Tests using the REST API**
.
Using `curl` to publish and query keys/values, you can:
```bash
# Put values that will be stored in the RocksDB database
curl -X PUT -d "TEST-1" http://localhost:8000/demo/example/test-1
curl -X PUT -d "B" http://localhost:8000/demo/example/a/b
.
# Retrive the values
curl http://localhost:8000/demo/example/**
```
.
-------------------------------
## Volume-specific storage configuration
Storages relying on a RocksDB-backed volume must specify some additional
configuration as shown [above](#setup-via-a-json5-configuration-file):
- **`"dir"`** (**required**, string) : The name of directory where the RocksDB
database is stored.
The absolute path will be `${ZENOH_BACKEND_ROCKSDB_ROOT}/`.
.
- **`"create_db"`** (optional, boolean) : create the RocksDB database if not
already existing. Not set by default.
*(the value doesn't matter, only the property existence is checked)*
.
- **`"read_only"`** (optional, boolean) : the storage will only answer to GET
queries. It will not accept any PUT or DELETE message, and won't put anything
in RocksDB database. Not set by default. *(the value doesn't matter, only the
property existence is checked)*
.
- **`"on_closure"`** (optional, string) : the strategy to use when the Storage
is removed. There are 2 options:
- *unset*: the database remains untouched (this is the default behaviour)
- `"destroy_db"`: the database is destroyed (i.e. removed)
.
-------------------------------
## **Behaviour of the backend**
.
### Mapping to RocksDB database
Each **storage** will map to a RocksDB database stored in directory:
`${ZENOH_BACKEND_ROCKSDB_ROOT}/`, where:
* `${ZENOH_BACKEND_ROCKSDB_ROOT}` is an environment variable that could be
specified before zenoh router startup.
If this variable is not specified `${ZENOH_HOME}/zenoh_backend_rocksdb`
will be used
(where the default value of `${ZENOH_HOME}` is `~/.zenoh`).
* `` is the `"dir"` property specified at storage creation.
Each zenoh **key/value** put into the storage will map to 2 **key/values** in
the database:
* For both, the database key is the zenoh key, stripped from the
`"strip_prefix"` property specified at storage creation.
* In the `"default"` [Column
Family](https://github.com/facebook/rocksdb/wiki/Column-Families) the key is
put with the zenoh encoded value as a value.
* In the `"data_info"` [Column
Family](https://github.com/facebook/rocksdb/wiki/Column-Families) the key is
put with a bytes buffer encoded in this order:
- the Timestamp encoded as: 8 bytes for the time + 16 bytes for the HLC
ID
- a "is deleted" flag encoded as a boolean on 1 byte
- the encoding prefix flag encoded as a ZInt (variable length)
- the encoding suffix encoded as a String (string length as a ZInt +
string bytes without ending `\0`)
.
### Behaviour on deletion
On deletion of a key, the corresponding key is removed from the `"default"`
Column Family. An entry with the
"deletion" flag set to true and the deletion timestamp is inserted in the
`"data-info"` Column Family
(to avoid re-insertion of points with an older timestamp in case of un-ordered
messages).
At regular interval, a task cleans-up the `"data-info"` Column Family from
entries with old timestamps and
the "deletion" flag set to true
.
### Behaviour on GET
On GET operations:
* if the selector is a unique key (i.e. not containing any `'*'`): the value
and its encoding and timestamp
for the corresponding key are directly retrieved from the 2 Column Families
using `get` RocksDB operation.
* if the selector is a key expression: the storage searches for matching
keys, leveraging RocksDB's [Prefix
Seek](https://github.com/facebook/rocksdb/wiki/Prefix-Seek) if possible to
minimize the number of entries to check.
.
-------------------------------
## 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-rocksdb/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
.
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-rocksdb` 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-rocksdb
```
.
-------------------------------
## 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.
.
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
```
Vcs-Browser: https://github.com/eclipse-zenoh/zenoh-backend-rocksdb
Vcs-Git: https://github.com/eclipse-zenoh/zenoh-backend-rocksdb
Package: zenoh-backend-rocksdb
Version: 1.0.3
Architecture: armel
Maintainer: zenoh-dev@eclipse.org
Installed-Size: 15307
Depends: zenoh-plugin-storage-manager (=1.0.3)
Filename: 1.0.3/zenoh-backend-rocksdb_1.0.3_armel.deb
Size: 3698516
MD5sum: 1ad1ec0df5b371bbe24f67cbd24f7262
SHA1: cc583cea1eb203737876bb4126d6f1b1c88838f8
SHA256: e82e5bfd4f9c6a80e3b8543b2b168e18186d35c34ae25ba5a4a2694b9ea45b25
Section: net
Priority: optional
Homepage: http://zenoh.io
Description: Backend for Zenoh using RocksDB
.
[](https://github.com/eclipse-zenoh/zenoh-backend-rocksdb/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.
.
-------------------------------
# RocksDB 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](http://zenoh.io/docs/manual/backends/) for more
details.
.
This backend relies on [RocksDB](https://rocksdb.org/) 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_rocksdb`**.
.
: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_rocksdb` library file is available in `~/.zenoh/lib`.
- Declare the `ZENOH_BACKEND_ROCKSDB_ROOT` environment variable to the
directory where you want the RocksDB databases
to be stored. If you don't declare it, the `~/.zenoh/zenoh_backend_rocksdb`
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 "storages" plugin:
storage_manager: {
volumes: {
// configuration of a "rocksdb" volume (the "zenoh_backend_rocksdb"
backend library will be loaded at startup)
rocksdb: {}
},
storages: {
// configuration of a "demo" storage using the "rocksdb" 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 database key.
// i.e.: "demo/example/a/b" will be stored as "a/b"
strip_prefix: "demo/example",
volume: {
id: "rocksdb",
// the RocksDB database will be stored in this directory
(relative to ${ZENOH_BACKEND_ROCKSDB_ROOT})
dir: "example",
// create the RocksDB database if not already existing
create_db: true
}
}
}
},
// Optionally, add the REST plugin
rest: { http_port: 8000 }
}
}
```
- Run the zenoh router with:
`zenohd -c zenoh.json5`
.
### **Setup at runtime via `curl` commands on the admin space**
.
- Run the zenoh router, with write permissions to its admin space:
`zenohd --adminspace-permissions rw`
- Add the "rocksdb" backend (the "zenoh_backend_rocksdb" library will be
loaded):
`curl -X PUT -H 'content-type:application/json' -d '{}'
http://localhost:8000/@/router/local/config/plugins/storage_manager/volumes/rocksdb`
- Add the "demo" storage using the "rocksdb" backend:
`curl -X PUT -H 'content-type:application/json' -d
'{key_expr:"demo/example/**",strip_prefix:"demo/example",volume: {id:
"rocksdb",dir: "example",create_db: true}}'
http://localhost:8000/@/router/local/config/plugins/storage_manager/storages/demo`
.
### **Tests using the REST API**
.
Using `curl` to publish and query keys/values, you can:
```bash
# Put values that will be stored in the RocksDB database
curl -X PUT -d "TEST-1" http://localhost:8000/demo/example/test-1
curl -X PUT -d "B" http://localhost:8000/demo/example/a/b
.
# Retrive the values
curl http://localhost:8000/demo/example/**
```
.
-------------------------------
## Volume-specific storage configuration
Storages relying on a RocksDB-backed volume must specify some additional
configuration as shown [above](#setup-via-a-json5-configuration-file):
- **`"dir"`** (**required**, string) : The name of directory where the RocksDB
database is stored.
The absolute path will be `${ZENOH_BACKEND_ROCKSDB_ROOT}/`.
.
- **`"create_db"`** (optional, boolean) : create the RocksDB database if not
already existing. Not set by default.
*(the value doesn't matter, only the property existence is checked)*
.
- **`"read_only"`** (optional, boolean) : the storage will only answer to GET
queries. It will not accept any PUT or DELETE message, and won't put anything
in RocksDB database. Not set by default. *(the value doesn't matter, only the
property existence is checked)*
.
- **`"on_closure"`** (optional, string) : the strategy to use when the Storage
is removed. There are 2 options:
- *unset*: the database remains untouched (this is the default behaviour)
- `"destroy_db"`: the database is destroyed (i.e. removed)
.
-------------------------------
## **Behaviour of the backend**
.
### Mapping to RocksDB database
Each **storage** will map to a RocksDB database stored in directory:
`${ZENOH_BACKEND_ROCKSDB_ROOT}/`, where:
* `${ZENOH_BACKEND_ROCKSDB_ROOT}` is an environment variable that could be
specified before zenoh router startup.
If this variable is not specified `${ZENOH_HOME}/zenoh_backend_rocksdb`
will be used
(where the default value of `${ZENOH_HOME}` is `~/.zenoh`).
* `` is the `"dir"` property specified at storage creation.
Each zenoh **key/value** put into the storage will map to 2 **key/values** in
the database:
* For both, the database key is the zenoh key, stripped from the
`"strip_prefix"` property specified at storage creation.
* In the `"default"` [Column
Family](https://github.com/facebook/rocksdb/wiki/Column-Families) the key is
put with the zenoh encoded value as a value.
* In the `"data_info"` [Column
Family](https://github.com/facebook/rocksdb/wiki/Column-Families) the key is
put with a bytes buffer encoded in this order:
- the Timestamp encoded as: 8 bytes for the time + 16 bytes for the HLC
ID
- a "is deleted" flag encoded as a boolean on 1 byte
- the encoding prefix flag encoded as a ZInt (variable length)
- the encoding suffix encoded as a String (string length as a ZInt +
string bytes without ending `\0`)
.
### Behaviour on deletion
On deletion of a key, the corresponding key is removed from the `"default"`
Column Family. An entry with the
"deletion" flag set to true and the deletion timestamp is inserted in the
`"data-info"` Column Family
(to avoid re-insertion of points with an older timestamp in case of un-ordered
messages).
At regular interval, a task cleans-up the `"data-info"` Column Family from
entries with old timestamps and
the "deletion" flag set to true
.
### Behaviour on GET
On GET operations:
* if the selector is a unique key (i.e. not containing any `'*'`): the value
and its encoding and timestamp
for the corresponding key are directly retrieved from the 2 Column Families
using `get` RocksDB operation.
* if the selector is a key expression: the storage searches for matching
keys, leveraging RocksDB's [Prefix
Seek](https://github.com/facebook/rocksdb/wiki/Prefix-Seek) if possible to
minimize the number of entries to check.
.
-------------------------------
## 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-rocksdb/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
.
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-rocksdb` 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-rocksdb
```
.
-------------------------------
## 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.
.
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
```
Vcs-Browser: https://github.com/eclipse-zenoh/zenoh-backend-rocksdb
Vcs-Git: https://github.com/eclipse-zenoh/zenoh-backend-rocksdb