#PERA Pure Erlang RESTful API to monitor the Erlang runtime.
About
PERA is a RESTful API that exposes as resources info about a running Erlang VM. This resources provide a simple way to access information about the Erlang runtime.
This API can be exploited to build more powerful tools like webapps or command line tools that give a simple and more focused view of the current state of the runtime.
Examples
Below is a request to GET the /processes/:pid resource:
Resources
The resources group info about the Erlang runtime in way that is easy an useful to consume. Most of the info is fetched using functions in the erlang module.
Available resources
The exposed resources are:
/: root of the API. Contains links to the other exposed resources.system: info about the emulator./processes: collection of all running processes./processes/:pid: a single running process./modules: collection of all the loaded modules./memory: memory usage in the runtime.
More resources will be added as the API is developed.
Media type
PERA uses HAL+json as the media type for representing its resources and their relations with hyperlinks. This has the following benefits:
- The resources share a simple but standarized format.
- Documentation can be discovered through the API.
- Relations can be discovered through the API.
- It is not reinventing the wheel. This means that there are already tools out there to consume APIs that use HAL as media type.
- Its human and machine readable.
Relations documentation
Location of the documentation for the relations accessible from a resource is given in the own resource. As the HAL spec says:
Link rels should be URLs which reveal documentation about the given link
"_links": {
"curies": {
"href": "/relations/{rel}",
"name": "pera",
"templated": true
},
"pera:modules": {
"href": "/modules"
},For example, the previous resource points out that you could find info about pera:modules at /relations/modules.
HAL browser
The HAL browser is included in the aplication to help with the usage of the API and to highlight the benefits of auto-discoverable resources. To use it, point your browser to http://localhost:8000/hal-browser/ and navigate through the available resources and documentation.
Usage
Start the PERA application and the API will be available at 0.0.0.0:8000.
TODO
- Add more resources. For example:
/modules/:module: info about a module./system/allocators: info about the current allocators./system/cpu: info about de CPU topology.
- Allow parameterized requests so the response contain only the neccesary info.
- Include a configuration file to easily setup PERA i.e. port, address, etc.
Tests
Unit test where done with the Eunit. To run them:
rake test
or, in case you don't have rake installed:
rebar eunit skip_deps=true
Contribute
Ideas are allways welcomed and if you find or think that something isn't working properly, just open an issue.
Pull requests and patches are welcome.
Author
This stuff has been writen by Farruco sanjurjo
- @madtrick at twitter
- Email at madtrick@gmail.com
If you like the project, please star it 😄
License
Copyright [2014] [Farruco Sanjurjo Arcay]
Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0 Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.