jd
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JSON diff and patch
JSON diff and patch
jd
is a commandline utility and Go library for diffing and patching JSON and YAML values. It supports a native jd
format (similar to unified format) as well as JSON Merge Patch (RFC 7386) and a subset of JSON Patch (RFC 6902). Try it out at http://play.jd-tool.io/.
Installation
To get the jd
commandline utility:
- run
brew install jd
, or - run
go install github.com/josephburnett/jd@latest
, or - visit https://github.com/josephburnett/jd/releases/latest and download the pre-built binary for your architecture/os, or
- run in a Docker image
jd(){ docker run --rm -i -v $PWD:$PWD -w $PWD josephburnett/jd "$@"; }
.
To use the jd
web UI:
- visit http://play.jd-tool.io/, or
- run
jd -port 8080
and visit http://localhost:8080.
Command line usage
Usage: jd [OPTION]... FILE1 [FILE2]
Diff and patch JSON files.
Prints the diff of FILE1 and FILE2 to STDOUT.
When FILE2 is omitted the second input is read from STDIN.
When patching (-p) FILE1 is a diff.
Options:
-color Print color diff.
-p Apply patch FILE1 to FILE2 or STDIN.
-o=FILE3 Write to FILE3 instead of STDOUT.
-set Treat arrays as sets.
-mset Treat arrays as multisets (bags).
-setkeys Keys to identify set objects
-yaml Read and write YAML instead of JSON.
-port=N Serve web UI on port N
-f=FORMAT Produce diff in FORMAT "jd" (default), "patch" (RFC 6902) or
"merge" (RFC 7386)
-t=FORMATS Translate FILE1 between FORMATS. Supported formats are "jd",
"patch" (RFC 6902), "merge" (RFC 7386), "json" and "yaml".
FORMATS are provided as a pair separated by "2". E.g.
"yaml2json" or "jd2patch".
Examples:
jd a.json b.json
cat b.json | jd a.json
jd -o patch a.json b.json; jd patch a.json
jd -set a.json b.json
jd -f patch a.json b.json
jd -f merge a.json b.json
Library usage
Note: import only release commits (v1.Y.Z
) because master
can be unstable.
import (
"fmt"
jd "github.com/josephburnett/jd/lib"
)
func ExampleJsonNode_Diff() {
a, _ := jd.ReadJsonString(`{"foo":"bar"}`)
b, _ := jd.ReadJsonString(`{"foo":"baz"}`)
fmt.Print(a.Diff(b).Render())
// Output:
// @ ["foo"]
// - "bar"
// + "baz"
}
func ExampleJsonNode_Patch() {
a, _ := jd.ReadJsonString(`["foo"]`)
diff, _ := jd.ReadDiffString(`` +
`@ [1]` + "\n" +
`+ "bar"` + "\n")
b, _ := a.Patch(diff)
fmt.Print(b.Json())
// Output:
// ["foo","bar"]
}
Diff language
- A diff is zero or more sections
- Sections start with a
@
header and the path to a node - A path is a JSON list of zero or more elements accessing collections
- A JSON number element (e.g.
0
) accesses an array - A JSON string element (e.g.
"foo"
) accesses an object - An empty JSON object element (
{}
) accesses an array as a set or multiset - After the path is one or more removals or additions, removals first
- Removals start with
-
and then the JSON value to be removed - Additions start with
+
and then the JSON value to added
EBNF
Diff ::= ( '@' '[' ( 'JSON String' | 'JSON Number' | 'Empty JSON Object' )* ']' '\n' ( ( '-' 'JSON Value' '\n' )+ | '+' 'JSON Value' '\n' ) ( '+' 'JSON Value' '\n' )* )*
Examples
@ ["a"]
- 1
+ 2
@ [2]
+ {"foo":"bar"}
@ ["Movies",67,"Title"]
- "Dr. Strangelove"
+ "Dr. Evil Love"
@ ["Movies",67,"Actors","Dr. Strangelove"]
- "Peter Sellers"
+ "Mike Myers"
@ ["Movies",102]
+ {"Title":"Austin Powers","Actors":{"Austin Powers":"Mike Myers"}}
@ ["Movies",67,"Tags",{}]
- "Romance"
+ "Action"
+ "Comedy"
Cookbook
Use git diff to produce a structural diff:
git difftool -yx jd @ -- foo.json
@ ["foo"]
- "bar"
+ "baz"
See what changes in a Kubernetes Deployment:
kubectl get deployment example -oyaml > a.yaml
kubectl edit deployment example
# change cpu resource from 100m to 200m
kubectl get deployment example -oyaml | jd -yaml a.yaml
output:
@ ["metadata","annotations","deployment.kubernetes.io/revision"]
- "2"
+ "3"
@ ["metadata","generation"]
- 2
+ 3
@ ["metadata","resourceVersion"]
- "4661"
+ "5179"
@ ["spec","template","spec","containers",0,"resources","requests","cpu"]
- "100m"
+ "200m"
@ ["status","conditions",1,"lastUpdateTime"]
- "2021-12-23T09:40:39Z"
+ "2021-12-23T09:41:49Z"
@ ["status","conditions",1,"message"]
- "ReplicaSet \"nginx-deployment-787d795676\" has successfully progressed."
+ "ReplicaSet \"nginx-deployment-795c7f5bb\" has successfully progressed."
@ ["status","observedGeneration"]
- 2
+ 3
apply these change to another deployment:
# edit file "patch" to contain only the hunk updating cpu request
kubectl patch deployment example2 --type json --patch "$(jd -t jd2patch ~/patch)"