Representational State Transfer (REST) is an architecture style that common in web application programming. Developed in tandem with HTTP/1.1, it encourages a representation of application object state within the underlying HTTP protocol transactions and an adherence to the semantics of the underlying HTTP verbs when applied to higher-level application state.

Simplistically, one of the key principles is that one should use the HTTP verbs in a manner that is consistent with the application object state. The table illustrates the different HTTP verbs and their specific applications:

In this recipe, we'll prepare a Junos OS router for accessing the REST API in order to allow a software client to make RPC calls using convenient HTTP/HTTPS access methods.

In order to complete this recipe, you'll need access to a Junos OS router device running at least Junos 14.2 or later because the REST feature is relatively new. At the time of writing, it is available on T, M, MX, and SRX-series Juniper router devices.

The steps for the following recipe are as follows:

1. Generate a private/public key-pair...

In this recipe, we'll use Python's built-in standard library routines for HTTPS in order to access the Junos OS REST API. We'll build an example app, rest.py, that allows a user to make simple RPC calls. In order to control the operation of the application, we'll define some command-line arguments.

In order to complete this recipe, you need access to a Junos OS router...

In this recipe, we'll make an example app, rest.js, using Node.js to connect to the Junos OS REST API in order to make procedure calls. We'll use Node.js's built-in HTTPS support, augmented with some extra external modules simply for convenience. For utility value, we'll provide some command-line options to customize how the application runs.

In order to complete this...

The previous recipes to connect to the Junos OS REST server might cause frustration for any application that needs to run in an unattended manner. Who will enter the password? This is not automation!

Dealing with the safe storage of security credentials can be tricky. The automation script needs to be able to read the credentials in a clear manner in order to complete the authentication process with the Junos OS device. But in most application execution environments, the permission to execute the app usually coincides with the permission to read the app executable file and, for just-in-time interpreted script languages, that includes the sensitive credentials.

People sometimes try to get around this problem by using a command line switch or an environment variable to store a password. This approach can be problematic though because, on most UNIX systems...

So far, we've only shown how to make use of operational RPCs. This allows us a fair amount of control and flexibility, but it's also possible to change the configuration of Junos OS through the REST API. In this recipe, we'll modify the previous Python code, rest.py, and make a modified version, rest-conf.py, that takes a configuration change as a text file and applies it to the specified Junos OS host, checking the loading process and the commit process as it goes.

In order to complete this recipe, you'll need a Python development environment with access to a Junos OS device upon which you've previously completed the REST API setup...