pkg/config/metadata.go

// Copyright 2020 Amazon.com, Inc. or its affiliates. All Rights Reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License"). You may
// not use this file except in compliance with the License. A copy of the
// License is located at
//
//     http://aws.amazon.com/apache2.0/
//
// or in the "license" file accompanying this file. This file is distributed
// on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either
// express or implied. See the License for the specific language governing
// permissions and limitations under the License.

package config

import (
	"encoding/json"

	"github.com/aws/amazon-ec2-metadata-mock/pkg/mock/static/types"

	"github.com/spf13/pflag"
)

const (
	// metadata keys
	mac                          = "mac"
	publicIpv4                   = "public-ipv4"
	iamSecurityCredentialsRole   = "iam-security-credentials-role"
	iamSecurityCredentials       = "iam-security-credentials"
	elasticInferenceAssociations = "elastic-inference-associations"
	elasticInferenceAccelerator  = "elastic-inference-accelerator"
	// prefixed with "mac" because query requires mac address and to avoid collisions with existing metadata keys
	// ex: network/interfaces/macs/<mac_address>/device-number
	macDeviceNumber            = "mac-device-number"
	macNetworkInterfaceId      = "mac-network-interface-id"
	macNetworkInterfaceCardIdx = "mac-network-interface-card-index"
	macIpv4Associations        = "mac-ipv4-associations"
	macIpv6Associations        = "mac-ipv6-associations"
	macLocalHostname           = "mac-local-hostname"
	macLocalIpv4s              = "mac-local-ipv4s"
	macMac                     = "mac-mac"
	macOwnerId                 = "mac-owner-id"
	macPublicHostname          = "mac-public-hostname"
	macPublicIpv4s             = "mac-public-ipv4s"
	macSecurityGroups          = "mac-security-groups"
	macSecurityGroupIds        = "mac-security-group-ids"
	macSubnetId                = "mac-subnet-id"
	macSubnetIpv4CidrBlock     = "mac-subnet-ipv4-cidr-block"
	macSubnetIpv6CidrBlocks    = "mac-subnet-ipv6-cidr-blocks"
	macVpcId                   = "mac-vpc-id"
	macVpcIpv4CidrBlock        = "mac-vpc-ipv4-cidr-block"
	macVpcIpv4CidrBlocks       = "mac-vpc-ipv4-cidr-blocks"
	macVpcIpv6CidrBlocks       = "mac-vpc-ipv6-cidr-blocks"
)

var (
	mdCfgPrefix       = "metadata."
	mdPathsCfgPrefix  = mdCfgPrefix + "paths."
	mdValuesCfgPrefix = mdCfgPrefix + "values."

	// mapping of mdValue KEYS to mdPath KEYS requiring path substitutions on override
	mdValueToPlaceholderPathsKeyMap = map[string][]string{
		// ex: "metadata.values.mac-address" : {"metadata.paths.network-interface-id", "metadata.paths.device-index", ...}
		mdValuesCfgPrefix + mac: {
			mdPathsCfgPrefix + macDeviceNumber, mdPathsCfgPrefix + macNetworkInterfaceId, mdPathsCfgPrefix + macNetworkInterfaceCardIdx, mdPathsCfgPrefix + macIpv4Associations, mdPathsCfgPrefix + macLocalHostname,
			mdPathsCfgPrefix + macLocalIpv4s, mdPathsCfgPrefix + macMac, mdPathsCfgPrefix + macOwnerId, mdPathsCfgPrefix + macPublicHostname, mdPathsCfgPrefix + macPublicIpv4s,
			mdPathsCfgPrefix + macSecurityGroups, mdPathsCfgPrefix + macSecurityGroupIds, mdPathsCfgPrefix + macSubnetId, mdPathsCfgPrefix + macSubnetIpv4CidrBlock, mdPathsCfgPrefix + macVpcId,
			mdPathsCfgPrefix + macVpcIpv4CidrBlock, mdPathsCfgPrefix + macVpcIpv4CidrBlocks, mdPathsCfgPrefix + macIpv6Associations, mdPathsCfgPrefix + macSubnetIpv6CidrBlocks, mdPathsCfgPrefix + macVpcIpv6CidrBlocks},
		mdValuesCfgPrefix + publicIpv4: {
			mdPathsCfgPrefix + macIpv4Associations},
		mdValuesCfgPrefix + iamSecurityCredentialsRole: {
			mdPathsCfgPrefix + iamSecurityCredentials},
		mdValuesCfgPrefix + elasticInferenceAssociations: {
			mdPathsCfgPrefix + elasticInferenceAccelerator},
	}

	// supported URL paths to run a mock
	mdPathsDefaults = map[string]interface{}{}

	// values in mock responses
	mdValuesDefaults = map[string]interface{}{}

	// mapping of metadata value keys to its nested struct
	mdNestedValues = map[string]interface{}{
		"metadata.values.elastic-inference-accelerator": types.ElasticInferenceAccelerator{},
	}
)

// GetCfgMdValPrefix returns the prefix to use to access metadata values in config
func GetCfgMdValPrefix() string {
	return mdCfgPrefix + "." + mdValuesCfgPrefix + "."
}

// GetCfgMdPathsPrefix returns the prefix to use to access metadata values in config
func GetCfgMdPathsPrefix() string {
	return mdCfgPrefix + "." + mdPathsCfgPrefix + "."
}

// BindMetadataCfg binds a flag that represents a metadata value to configuration
func BindMetadataCfg(flag *pflag.Flag) {
	bindFlagWithKeyPrefix(flag, mdValuesCfgPrefix)
}

// SetMetadataDefaults sets config defaults for metadata paths and values
func SetMetadataDefaults(jsonWithDefaults []byte) {
	// Unmarshal to map to preserve keys for Paths and Values
	var defaultsMap map[string]interface{}
	json.Unmarshal(jsonWithDefaults, &defaultsMap)

	mdPaths := defaultsMap["metadata"].(map[string]interface{})["paths"].(map[string]interface{})
	mdValues := defaultsMap["metadata"].(map[string]interface{})["values"].(map[string]interface{})

	for k, v := range mdPaths {
		newKey := mdPathsCfgPrefix + k
		// ex: "metadata.paths.ami-id": "/latest/meta-data/ami-id"
		mdPathsDefaults[newKey] = v
	}

	for k, v := range mdValues {
		newKey := mdValuesCfgPrefix + k
		// ex: "metadata.values.ami-id": "ami-0a887e401f7654935"
		mdValuesDefaults[newKey] = v

		// if mdvalue is a nested struct, then re-unmarshal json data to correct type
		if nestedStruct, ok := mdNestedValues[newKey]; ok {
			updatedVal, err := unmarshalToNestedStruct(v, nestedStruct)
			if err == nil {
				mdValuesDefaults[newKey] = updatedVal
			}
		}
	}

	LoadConfigFromDefaults(mdPathsDefaults)
	LoadConfigFromDefaults(mdValuesDefaults)
}

// GetMetadataDefaults returns config defaults for metadata paths and values
func GetMetadataDefaults() (map[string]interface{}, map[string]interface{}) {
	return mdPathsDefaults, mdValuesDefaults
}

// GetMetadataValueToPlaceholderPathsKeyMap returns collection of metadata values that are substituted into paths
func GetMetadataValueToPlaceholderPathsKeyMap() map[string][]string {
	return mdValueToPlaceholderPathsKeyMap
}

// unmarshalToNestedStruct returns a struct with its nested values populated correctly
func unmarshalToNestedStruct(originalValue interface{}, unmarshalToStruct interface{}) (interface{}, error) {
	valAsJson, err := json.Marshal(originalValue)
	if err != nil {
		return nil, err
	}

	// all supported nested structs
	switch unmarshalToStruct.(type) {
	case types.ElasticInferenceAccelerator:
		nestedStruct, ok := unmarshalToStruct.(types.ElasticInferenceAccelerator)
		if ok {
			if err = json.Unmarshal(valAsJson, &nestedStruct); err != nil {
				return nil, err
			}
			return nestedStruct, nil
		}
	}
	return nil, nil
}