Export all Custom Metadata Records in CSV file using Apex

SK_CustomMetadataUtility.apxc

public class SK_CustomMetadataUtility {

    public static void exportAllCMRecordsInCSV(){
        Map<string,List<string>> objToFieldsMap = new Map<string,List<string>>();
        Map<String, Schema.SObjectType> schemaMap = Schema.getGlobalDescribe();
        for(String ss1: schemaMap.keyset()){
            Schema.SObjectType objToken=schemaMap.get(ss1);
            //find details about sobject
            Schema.DescribeSObjectResult objDescribe=objToken.getdescribe();
            string objAPIName= string.valueof(objDescribe.getName());
            //filter object for which APi name ends with _mdt
            //filter manage package objects as they contain __ twice in their API name
            if(objAPIName.endsWith('__mdt') && objAPIName.countMatches('__')==1){
                //system.debug('***custom metadata name:'+objAPIName);
                objToFieldsMap.put(objAPIName,new List<string>());
                //finding all fields of sobjects
                Map<String, Schema.SObjectField> fieldMap = objDescribe.fields.getMap(); 
                objToFieldsMap.get(objAPIName).add('DeveloperName');
                objToFieldsMap.get(objAPIName).add('MasterLabel');
                for(String ss:Fieldmap.keyset()){
                    Schema.DescribeFieldResult fd=fieldMap.get(ss).getDescribe();
                    string fieldAPIName=string.valueof(fd.getName());
                    //check if field is custom or not
                    if(fd.isCustom()){
                        objToFieldsMap.get(objAPIName).add(fieldAPIName);
                    }
                }
            }
        }
        system.debug('**objToFieldsMap size:'+objToFieldsMap.size());
        system.debug('**objToFieldsMap:'+objToFieldsMap);
        integer count =0;
        
        
        string csvString = 'Name,DeveloperName,MasterLabel,Fields\n';
        
        for(string objAPIName: objToFieldsMap.keyset()){
            if(count<100){ //here we are restricting script to export only 100 custom metadata records
                Map<string,List<string>> developerNameWithFieldValuesMap= new Map<string,List<string>>();
                String qryString = 'SELECT '+ string.join(objToFieldsMap.get(objAPIName),',') +' From '+objAPIName;
                system.debug('**qryString-'+objAPIName+'-:'+qryString);
                for(sobject sb: Database.query(qryString)){
                    string developerName= string.valueof(sb.get('developerName'));
                    developerNameWithFieldValuesMap.put(developerName,new List<string>());
                    for(string field: objToFieldsMap.get(objAPIName)){
                        if(sb.get(field)!=null && field!='developerName' && field!='MasterLabel'){
                            //Fields coulm will contains Field API and its corresponding value 
                            //here &SK& is delimiter to differentiate the API name with value
                            developerNameWithFieldValuesMap.get(developerName).add(field+'&SK&'+sb.get(field));
                        }
                    }
                    csvString = csvString + objAPIName+','+string.valueof(sb.get('DeveloperName')).escapeCsv()+','+ string.valueof(sb.get('MasterLabel')).escapeCSV()+','+ string.join(developerNameWithFieldValuesMap.get(developerName),',').escapecsv()+'\n';
                }
                count= +1;
            }
        }
        
        
        Messaging.EmailFileAttachment csvAttc = new Messaging.EmailFileAttachment();
        blob csvBlob = Blob.valueOf(csvString);
        string csvname= 'Custom metadata records.csv';
        csvAttc.setFileName(csvname);
        csvAttc.setBody(csvBlob);
        Messaging.SingleEmailMessage email =new Messaging.SingleEmailMessage();
        String[] toAddresses = new list<string> {UserInfo.getUserEmail()};
        String subject = 'Custom metadata records -'+system.now();
        email.setSubject(subject);
        email.setToAddresses( toAddresses );
        email.setPlainTextBody(subject);
        email.setFileAttachments(new Messaging.EmailFileAttachment[]{csvAttc});
        Messaging.SendEmailResult [] r = Messaging.sendEmail(new Messaging.SingleEmailMessage[] {email});
    }
    
}