diff-docker-compose

diff-docker-compose

Inspired by adamdicarlo/diff-docker-compose but in Go.

Small utility to diff two docker-compose.yml files; useful, for instance, if your docker-compose.yml is based off of a template.

By default, running with no arguments will assume the two yaml files to diff are docker-compose.yml.template and docker-compose.yml.

Currently, this only gives a high-level overview of how the files compare to each other.

Go API

lib.DiffYaml(oldYaml map[string]interface{}, newYaml map[string]interface{}) YamlDiffResult

DiffYaml compares two map[string]interface{} objects (e.g. read via YAML parser).

Arguments:

• oldYaml: map structure of the YAML file considered the old or current state
• newYaml: map structure of the YAML file considered the new or desired state

Returns:

• YamlDiffResult object

YamlDiffResult

This is the result object returned by the DiffYaml method.

Properties:

• Diffs []YamlDiffEntry: list of all nodes with differences.
• Structure map[string]*YamlDiffStructure: tree structure of both YAML files combined

Methods:

• HasChanged(path []string) bool: returns true when there differences for the node
• GetAll(path []string) []YamlDiffEntry: returns differences for the node identified by the selector (e.g. GetAll([]string{"services"}) or GetAll([]string{"services", "myapp"}))
• GetStructure(path []string) *YamlDiffStructure: returns the structure for the node identified by the path. Access the diff for that node or its children for diff information.

Note: When a node is added, the whole node will be listed as difference in YamlDiffEntry (obtained via GetAll()). If you need to traverse the node's children and look for changes, use GetStructure.

Examples:

result := lib.DiffYaml(composeTemplate, composeActual)
fmt.Println(result.GetAll([]string{"services"}))

// this will get all differences of the "service" node
fmt.Println(result.GetStructure([]string{"services"}).GetDiff())

// both lines below will get only the differences of the "app2" service
fmt.Println(result.GetStructure([]string{"services", "app2"}).GetDiff())
result.GetStructure([]string{"services"}).GetChildren()["app2"].GetDiff()

[{[services app3] <nil> map[image:myapp:latest]} {[services db-service] <nil> map[image:db:latest]} {[services user-service environment] [SECRET=SET_ME] [SECRET=MYSECRET123]} {[services app2] map[image:myapp:latest] <nil>}]
{[services] map[app2:map[image:myapp:latest] user-service:map[environment:[SECRET=SET_ME] image:user-service:latest] web:map[build:. ports:[8000:5000]]] map[app3:map[image:myapp:latest] db-service:map[image:db:latest] user-service:map[environment:[SECRET=MYSECRET123] image:user-service:latest] web:map[build:. ports:[8000:5000]]]}
{[services app2] map[image:myapp:latest] <nil>}
{[services app2] map[image:myapp:latest] <nil>}