custom-json-diff

Comparing two JSON files presents an issue when the two files have certain fields which are dynamically generated (e.g. timestamps), variable ordering, or other field which need to be excluded for one reason or another. Enter custom-json-diff, which allows you to specify fields to ignore in the comparison and sorts all fields.

Installation

pip install custom-json-diff

CLI Usage

usage: cjd [-h] -i INPUT INPUT [-o OUTPUT] (-c CONFIG | -x EXCLUDE [EXCLUDE ...] | -p {cdxgen,cdxgen-extended}) {bom-diff} ...

positional arguments:
  {bom-diff}            subcommand help
    bom-diff            compare CycloneDX BOMs

options:
  -h, --help            show this help message and exit
  -i INPUT INPUT, --input INPUT INPUT
                        Two JSON files to compare.
  -o OUTPUT, --output OUTPUT
                        Export JSON of differences to this file.
  -c CONFIG, --config-file CONFIG
                        Import TOML configuration file.
  -x EXCLUDE [EXCLUDE ...], --exclude EXCLUDE [EXCLUDE ...]
                        Exclude field(s) from comparison.
  -p {cdxgen,cdxgen-extended}, --preset {cdxgen,cdxgen-extended}
                        Preset to use

bom-diff usage

usage: cjd bom-diff [-h] [-a] [-r REPORT_TEMPLATE]

options:
  -h, --help            show this help message and exit
  -a, --allow-new-versions
                        Allow new versions in BOM comparison.
  -r REPORT_TEMPLATE, --report-template REPORT_TEMPLATE
                        Jinja2 template to use for report generation.

Specifying fields to exclude

To exclude fields from comparison, use the -x or --exclude flag and specify the field name(s) to exclude. The json will be flattened, so fields are specified using dot notation. For example:

{
    "field1": {
        "field2": "value", 
        "field3": [
            {"a": "val1", "b": "val2"}, 
            {"a": "val3", "b": "val4"}
        ]
    }
}

is flattened to:

{
    "field1.field2": "value",
    "field1.field3.[0].a": "val1",
    "field1.field3.[0].b": "val2",
    "field1.field3.[1].a": "val3",
    "field1.field3.[1].b": "val4"
}

To exclude field2, you would specify field1.field2. To exclude the a field in the array of objects, you would specify field1.field3.[].a (do NOT include the array index, just do []). Multiple fields may be specified separated by a space. To better understand what your fields should be, check out json-flatten, which is the package used for this function.

Note: In the context of BOM diffing, this list is only used for the metadata, not the components, services, or dependencies.

Sorting

custom-json-diff will sort the imported JSON alphabetically. If your JSON document contains arrays of objects, you will need to specify any keys you want to sort by in a toml file or use a preset. The first key located from the provided keys that is present in the object will be used for sorting.

TOML config file example

[settings]
excluded_fields = ["serialNumber", "metadata.timestamp"]
sort_keys = ["url", "content", "ref", "name", "value"]

[bom_diff]
allow_new_versions = false
report_template = "my_template.j2"