iControl REST + jq Cookbook - Readme

This series describes convenient methods for extracting meaningful information from lengthy and often verbose iControl REST responses using a third party tool called jq.

To extract specific data from an iControl REST JSON text response, such as a virtual server name or pool member IP address, most often, you would try good old Unix utilities such as grep, sed or awk. You would pipe multiple commands if a single command does not satisfy you. If you have ever craved for a neater way, consider using jq - A tool specifically designed for parsing and filtering JSON texts.

jq is bundled with BIG-IP. If your client system does not have one, you can install it via a package management tool such as yum or apt. Alternatively, you can download the binary from Download jq. You can copy it to any directory as it does not have any dependency.

Although jq for Windows is available, Windows command prompt is picky about quotes and escapes. The jq filter examples in the documents are for bash, hence you may need to tweak them to satisfy peculiar Window's needs. Consider enabling Windows Subsystem for Linux (WSL) to use bash on Windows.

If you are unfamiliar with JSON, please take a look at RFC 8259: "The JavaScript Object Notation (JSON) Data Interchange Format". Don't worry. It's just 16 pages long.

Part01 - Basics
Format the entire JSON body
Sort by property names
Extract a specific property
Error
Substitute the authentication token to a shell variable
Extract multiple properties
Format the output
Count a number of objects
Iterate through an array
Obtain the full pool information
Part02 - Intermediate [To be published]
Extract an array element
Slice an array
Find the element
Find matching elements
Extract property names and values
Extract a property from deeply nested object
Tabularize all the version information
Process raw monitor output
Format 'list sys global-settings' output
Convert Unix epoch time
Part03 - Advanced topics [To be published]
Replicate an object with slight modifications
Modify internal data-group records
Process restjavad-autit.log
Process restjavad-api-usage.log
Get a list of the latest Automation Toolchain

Examples

The examples in this series use curl for sending iCotnrol REST requests. The response JSON body is fed into the jq's stdin via pipe as below.

curl -sku admin:admin https://<host>/mgmt/tm/sys/version | jq '.'

The -s curl option is for disabling its progress bar (--silent). The -k option is for skipping server certificate verification (--insecure). The -u is to provide the user name and password (--user): The examples use the user 'admin' with the password 'admin'. Please change them. The <host> in the URL is the management IP of the target BIG-IP.

The example output is shown directly below the call:

curl -sku $PASS https://$HOST/mgmt/tm/sys/version | jq '.'
{                               # output starts from here
 "kind": "tm:sys:version:versionstats",
 "selfLink": "https://localhost/mgmt/tm/sys/version?ver=15.1.2",
 "entries": {
  "https://localhost/mgmt/tm/sys/version
  ...                            # Skipped