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Perform upsert on maps in golang

Time:05-24

So I have 2 configs, one you can say its kinda like default config and another based on request the attributes needs to be either updated or inserted.

Example of both:

var (
currentConfig = `{
    "config": {
        "type": "func1",
        "properties": {
            "param1": "10",
            "param2": "10"
        },
        "connected": [
            {
                "type": "func2",
                "properties": {
                    "param1": "20",
                    "param2": "20"
                },
                "connected": [
                    {
                        "type": "func3",
                        "properties": {},
                        "connected": [
                            {}
                        ]
                    }
                ]
            }
        ]
    }
}`

updateRequest = `{
    "config": {
        "type": "func1",
        "properties": {},
        "connected": [
            {
                "type": "func2",
                "properties": {
                    "param1": "30",
                },
                "connected": [
                    {
                        "type": "func3",
                        "properties": {
                            "param1": "20",
                            "param2": "20"
                        },
                        "connected": [
                            {}
                        ]
                    }
                ]
            }
        ]
    }
}`
)

Im able to iterate through one map but was wondering how to pass both configs/maps and check if attribute exists or not. Any help would be appreciated.

func checkkeyPairExists(value interface{}) {
    switch value.(type) {
    case []interface{}:
        for _, v := range value.([]interface{}) {
            checkkeyPairExists(v)
        }
    case map[string]interface{}:
        for k, v := range value.(map[string]interface{}) {
            fmt.Println(k, v)
            checkkeyPairExists(v)
        }

    }
}

The desired output:

{
    "config": {
        "type": "func1",
        "properties": {
            "param1": "10",
            "param2": "10"
        },
        "connected": [
            {
                "type": "func2",
                "properties": {
                    "param1": "20",
                    "param2": "30"
                },
                "connected": [
                    {
                        "type": "func3",
                        "properties": {
                            "param1": "20",
                            "param2": "20"
                        },
                        "connected": [
                            {}
                        ]
                    }
                ]
            }
        ]
    }
}

CodePudding user response:

You have to recursively descend both of them:

func checkkeyPairExists(value1, value2 interface{}) {
    switch value1.(type) {
    case []interface{}:
        v2, ok:=value2.([]interface{})
        if !ok {
          // error, or ignore and return
        }
        // merge value1 and v2
    case map[string]interface{}:
        m2, ok:=value2.(map[string]interface{})
        if !ok {
            // error, or ignore and return
        }
        for k, v := range value1 {
            if v2, exists:=m2[k]; exists {
               // k exists in value2
            } else {
               // k is not in value2
            }
        }

    }
}

CodePudding user response:

It's tough to recommend a full solution without knowing more details about the safe assumptions about your data/schema but I can take a shot with what you have here.

Limiting your concepts a bit from interface to a struct representing your nodes will probably make things a bit easier here.

type ConfigNode struct {
    Type       string
    Properties map[string]string
    Connected  []*ConfigNode
}

func (n *ConfigNode) PatchProperties(patch *ConfigNode) {
    for k, v := range patch.Properties {
        n.Properties[k] = v
    }
}

func (n ConfigNode) ShallowClone() ConfigNode {
    clone := ConfigNode{
        Type:       n.Type,
        Properties: make(map[string]string),
        Connected:  make([]*ConfigNode, 0),
    }
    clone.PatchProperties(&n)

    return clone
}

func (n *ConfigNode) PrintTree() string {
    builder := strings.Builder{}
    n.appendToTreePrint(&builder, 0)

    return builder.String()
}

func (n *ConfigNode) appendToTreePrint(builder *strings.Builder, depth int) {
    isRoot := builder == nil
    tab := strings.Repeat("\t", depth)
    if isRoot {
        builder = &strings.Builder{}
    }

    builder.WriteString(tab)
    builder.WriteString(n.Type)
    builder.WriteRune('\n')

    for k, v := range n.Properties {
        builder.WriteString(fmt.Sprintf("%s - %s => %s\n", tab, k, v))
    }

    for _, c := range n.Connected {
        c.appendToTreePrint(builder, depth 1)
    }
}

func mergeNodes(base []*ConfigNode, patch []*ConfigNode) []*ConfigNode {
    merged := make([]*ConfigNode, 0)

    if patch == nil {
        // No patch is being applied, just deep copy the base nodes.
        for _, node := range base {
            clone := node.ShallowClone()
            clone.Connected = mergeNodes(clone.Connected, nil)
            merged = append(merged, &clone)
        }

        return merged
    }

    baseTypes := make(map[string]*ConfigNode)
    patchTypes := make(map[string]*ConfigNode)

    // Key the nodes by their Type so we can match them.
    for _, node := range base {
        baseTypes[node.Type] = node
    }
    for _, node := range patch {
        patchTypes[node.Type] = node
    }

    for k, v := range baseTypes {
        mergedNode := v.ShallowClone()

        if patchNode, ok := patchTypes[k]; ok {
            // A patch node was found with the Type matching the base, combine the two.
            mergedNode.PatchProperties(patchNode)
            // Remove the patch node so we don't iterate through it later.
            delete(patchTypes, k)

            // Recurse in and merge child nodes.
            mergedNode.Connected = mergeNodes(v.Connected, patchNode.Connected)
        } else {
            // There is no patch so we can just deep copy the children.
            mergedNode.Connected = mergeNodes(v.Connected, nil)
        }

        merged = append(merged, &mergedNode)
    }

    // Any unmatched patch nodes can be deep copied into the output.
    for _, v := range patchTypes {
        mergedNode := v.ShallowClone()
        mergedNode.Connected = mergeNodes(v.Connected, nil)
        merged = append(merged, &mergedNode)
    }

    return merged
}

func printConfig(name string, config []*ConfigNode) {
    fmt.Println(name   ":")
    for _, v := range config {
        fmt.Println(v.PrintTree())
    }
}

func initTestNodes() (base []*ConfigNode, patch []*ConfigNode) {
    var node1Base ConfigNode
    var node2Base ConfigNode
    var node3Base ConfigNode

    var node1Patch ConfigNode
    var node3Patch ConfigNode
    var node4Patch ConfigNode

    node1Base = ConfigNode{
        Type: "func1",
        Properties: map[string]string{
            "params1": "orig1",
            "params2": "orig1",
        },
        Connected: []*ConfigNode{&node2Base},
    }
    node2Base = ConfigNode{
        Type: "func2",
        Properties: map[string]string{
            "params1": "orig2",
            "params2": "orig2",
        },
        Connected: []*ConfigNode{&node3Base},
    }
    node3Base = ConfigNode{
        Type: "func3",
        Properties: map[string]string{
            "params1": "orig3",
            "params2": "orig3",
        },
        Connected: []*ConfigNode{},
    }
    node1Patch = ConfigNode{
        Type: "func1",
        Properties: map[string]string{
            "params1": "up1",
        },
        Connected: []*ConfigNode{&node4Patch},
    }
    node3Patch = ConfigNode{
        Type: "func3",
        Properties: map[string]string{
            "params1": "up3",
        },
        Connected: []*ConfigNode{},
    }
    node4Patch = ConfigNode{
        Type: "func4",
        Properties: map[string]string{
            "params1": "up4",
        },
        Connected: []*ConfigNode{&node3Patch},
    }

    return []*ConfigNode{&node1Base}, []*ConfigNode{&node1Patch}
}

func main() {
    baseConfig, patchConfig := initTestNodes()
    merged := mergeNodes(baseConfig, patchConfig)

    printConfig("Base Config", baseConfig)
    printConfig("Patch Config", patchConfig)
    printConfig("Merged Config", merged)
}
  •  Tags:  
  • go
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