bprc 0.7.0

What it does

If you’re a Dev/DevOps engineer you may have been faced with a situation where you find yourself writing a shell script to automate getting JSON data from one or more RESTful endpoints using curl or wget or httpie, and then parsing the output using sed, grep or jq. This tool is designed to provide a generic, simplied, yet powerful means of writing such scripts in the form of a simple recipe specification, rather than a shell script.

It relies on the excellent Pygments and Requests libraries.

To install

This is a Python application which is written in Python 3. It has only currently been tested on Linux (Ubuntu 14.04).

$ apt-get install -y python3
$ apt-get install -y python3-pip

$ pip3 install bprc

$ pip3 install https://github.com/bradwood/BPRC/tarball/x.y.x # replace with version tag in GitHub, no tar.gz extension needed

How it works

The recipe is specified in a single YAML file which describes: - A list of variables that are initialised at the top of the recipe for use in the steps below. - A list of ordered steps that comprise the recipe, each containing some or all of the below: - the URL that need to be visited - the HTTP method to use - the headers, querystring and body data to include in the step - specific options to pass into the this step – currently only the following options are supported: - request.retries - set to the number of retries to attempt on the step in question. Only works for non-mutating calls (e.g., GETs), defaults to 3. - request.body_format - can be set to json (default) or form. Will assemble the request body as either form-encoded or json and set the Content-type: header to application/x-www-form-urlencoded or application/json respectively.

Additionally, the YAML recipe file supports the ability to grab data from any part of any of the HTTP requests or responses in earlier steps in the recipe and insert them into later steps using a PHP-like construct. For example, say I have a 10-step recipe specified and in step 7 I need to POST some data that I received in step 3’s reponse. I can include a construct like this in any part of the YAML file:

<%=steps[3].response.body["id"]%>

Assuming that step 3 did indeed contain a parameter called id in it’s JSON response payload, this data will then be substituted in the specified part of step 10’s request.

The insertion of variables anywhare in the recipe is done as shown:

<%!varname%>

Files can also be included into a recipe using a construct like this:

<%f/path/to/file.txt%>

--- #sample recipe
variables:
    name: brad
    favourite_colour: red
    age: 345
    drinks_beer: true
    age_and_colour: <%!age%>:<%!favourite_colour%>
    lorumfile: <%f./examples/lorum.txt%>

recipe:
    -  # step0
        name: Call Mockbin # see http://mockbin.org/docs#http-request
        httpmethod: POST
        # using the HTTP Basic auth process to see if the Authorization: header
        # is visible in the output file.
        URL: http://Aladdin:OpenSesame@mockbin.org/request/path/to/<%!name%>
        request:
            body:
                name: My name is <%!name%>
                age: I am <%!age%> years old.
                beer_drinker: <%!drinks_beer%>
                lorum_impsum: <%!lorumfile%>
            querystring:
                colors: blue, green,  <%!favourite_colour%>
            headers:
                X-info: <%!age_and_colour%>
    -
        name: Call Mockbin with data from the previous call.
        httpmethod: GET
        options:
            request.retries: 10  #set retries to 10, overriding the default of 3.
        URL: http://mockbin.org/request/path/to/<%!name%>
        request:
            headers:
                date_header_from_previous_call: <%=steps[0].response.headers["Date"]%>
            body:
                http_response_code_from_previous_call: <%=steps[0].response.code%>

Other features

bprc provides the following features: - robust logging support - saving output files as raw HTTP (response only, or both request and response) or JSON - SSL support (including the ability to ingore invalid server certificates) - verbose and/or debug output - HTTP request bodies formatted either as JSON or form-encoded - Pretty-printed output

Known issues/shortcomings

The following are known areas for improvement: - poor tolerance of badly formatted YAML - --dry-run option not implemented - poor test coverage and test automation - only handles JSON in the response bodies, XML or ther payload types are not supported.

Planned improvements

• improving error handling

• better test coverage

• Implementing --dry-run

• passing an entire payload, rather than just a single parameter, using a file include

• setting a recipe variable via cli and/or environment variable

Contributing

Contributions are welcome! Please fork, make your changes, add tests to cover your work and then raise a pull request.