Overview

VSG can use a configuration file to alter it’s behavior and/or include a list of files to analyze. This is accomplished by passing JSON and/or YAML file(s) through the –configuration command line argument. This is the basic form of a configuration file in JSON:

{
  "file_list": [
    "fifo.vhd",
    "$PATH_TO_FILE/spi_master.vhd",
    "$OTHER_PATH/src/*.vhd",
    "source/spi.vhd": {
      "rule": {
        "ruleId_ruleNumber":"blah"
      }
    }
  ],
  "local_rules":"$DIRECTORY_PATH",
  "rule": {
    "global": {
      "attributeName":"AttributeValue"
    },
    "group": {
      "group_name": {
        "attributeName":"AttributeValue"
      }
    }
    "ruleId_ruleNumber": {
      "attributeName":"AttributeValue"
    }
  }
}

This is the basic form of a configuration file in YAML:

file_list:
  - fifo.vhd
  - source/spi.vhd:
      rule:
        ruleId_ruleNumber:
          attributeName: AttributeValue
  - $PATH_TO_FILE/spi_master.vhd
  - $OTHER_PATH/src/*.vhd
local_rules: $DIRECTORY_PATH
rule:
  global:
    attributeName: AttributeValue
  group:
    group_name:
      attributeName : AttributeValue
  ruleId_ruleNumber:
    attributeName: AttributeValue

It is not required to have file_list, local_rules, and rule defined in the configuration file. Any combination can be defined, and the order does not matter.

Note

All examples of configurations in this documentation use JSON. However, YAML can be used instead.

file_list

The file_list is a list of files that will be analyzed. Environment variables will expanded. File globbing is also supported. The Environment variables will be expanded before globbing occurs. This option can be useful when running VSG over multiple files.

Rule configurations can be specified for each file by following the format of the rule configuration.

local_rules

Local rules can be defined on the command line or in a configuration file. If they are defined in both locations, the configuration will take precedence.

rule

Any attribute of any rule can be configured. Using global will set the attribute for every rule. Using group will set attributes for groups of rules. Each rule is addressable by using it’s unique ruleId and ruleNumber combination. For example, whitespace_006 or port_010.

Note

If global and unique attributes are set at the same time, the unique attribute will take precedence.

Here are a list of attributes that can be altered for each rule:

Attribute Values Description
indentSize Integer Sets the number of spaces for each indent level.
phase Integer Sets the phase the rule will run in.
disable Boolean If set to True, the rule will not run.
fixable Boolean If set to False, the violation will not be fixed

Reporting Single Rule Configuration

The configuration for a single rule can be reported using the -rc option:

$ vsg -rc entity_001
{
  "rule": {
    "entity_001": {
      "indentSize": 2,
      "phase": 4,
      "disable": false,
      "fixable": true
    }
  }
}

VSG will print the configuration for the rule given in a JSON format. This configuration can be altered and added to a configuration file.

Reporting Configuration for All Rules

Every rule configuration can be report and saved to a file using the -oc option:

$ vsg -oc configuration.json

The output file will be in JSON format and can be modified and passed back to VSG using the -c option.

Rule Configuration Priorities

There are three ways to configure a rule. From least to highest priority are:

  • [rule][global]
  • [rule][group]
  • [rule][<identifier>]
  • [file_list][<filename>][rule][<identifier>].

If the same rule is defined in all four locations as in the example below, then the final setting will be equal to the highest priority.

 {
   "file_list":[
     "entity.vhd":{
       "rule":{
         "length_001":{
           "disable": true
         }
       }
    },
    "architecture.vhd",
    "package.vhd"
   ],
   "rule":{
     "global":{
       "disable": true
     },
     "group":{
       "length": {
         "disable": false
       }
     },
     "rule": {
       "length_001":{
         "disable": false
     }
   }
 }
}

In this example configuration, all rules are disabled by the global configuration. Then rule length_001 is enabled for the files architecture.vhd, package.vhd and entity.vhd by the rule configuration. Then rule length_001 is disabled for the file entity.vhd.

Example: Disabling a rule

Below is an example of a JSON file which disables the rule entity_004

{
    "rule":{
        "entity_004":{
            "disable":true
        }
    }
}

Use the configuration with the –configuration command line argument:

$ vsg -f RAM.vhd --configuration entity_004_disable.json

Example: Setting the indent increment size for a single rule

The indent increment size is the number of spaces an indent level takes. It can be configured on an per rule basis…

{
    "rule":{
        "entity_004":{
            "indentSize":4
        }
    }
}

Example: Setting the indent increment size for all rules

Configure the indent size for all rules by setting the global attribute.

{
    "rule":{
        "global":{
            "indentSize":4
        }
    }
}

Example: Enabling only indent rules

Configure the indent size for all rules by setting the global attribute.

{
    "rule":{
        "global":{
            "indentSize":4
        },
        "group":{
            "indent":{
                "disable":False
            }
        }
    }
}