How to create index mapping in Elastic.Clients.Elasticsearch for .Net

Question

I'm using version 8 of the .NET 'Elastic.Clients.Elasticsearch' nuget package and trying to create an index mapping based on the below model. How do I map the Employee members and their JobRole members? I tried using "Object" and "Nested", without luck.

Furthermore how do I exclude properties from being indexed? Attribute mappings like:

[Text(Name = "last_name")]

... are no longer supported in version 8. The only option is "fluent mapping".

Unfortunately there's only documentation available for version 7, https://www.elastic.co/guide/en/elasticsearch/client/net-api/7.17/fluent-mapping.html

public class Company
{
    public string CompanyName { get; set; }
    public Employee EmployeeInfo { get; set; }
}


public class Employee
{
    public string EmployeeName { get; set; }
    public JobRole[] JobRoles { get; set; }
}


public class JobRole
{
    public string RoleName { get; set; }
}

This is my code and as you can see I got lost halfway..

var createIndexResponse = client.Indices.Create<Company>("myindex", c => c
            .Mappings(m => m
                .Properties(p => p
                    .Keyword(s => s.CompanyName)
                 .Object<Employee> (x=>x.EmployeeInfo.EmployeeName  // Got lost here...
                )
            )
        );

Anyone?

Fancher

Just wanted to +1 your question. I'm in the same boat - did you make any progress? – Arlana

@Arlana No I didn't. Very disappointing! I installed version 7. – Fancher

I did some reading up and it appears that its not GA yet so it's best to use v7 whilst the full api is being developed – Arlana

Attribute Mappings won't be implemented in v8, you have to use Fluent API. elastic.co/guide/en/elasticsearch/client/net-api/8.9/… – Coaptation

Answer 1

When creating new Properties, the IProperty it requests are the property types you'd assign to a field. Like TextProperty, ObjectProperty, NestedProperty, LongProperty:

    var response = await _client.Indices.CreateAsync<Company>("myindex", c => c
        .Mappings(map => map
            .Properties(p => p
            .Text(t => t.CompanyName)
            .Object(o => o.EmployeeInfo, objConfig => objConfig
                .Properties(p => p
                    .Text(t => t.EmployeeInfo.EmployeeName)
                    .Object(n => n.EmployeeInfo.JobRoles, objConfig => objConfig
                        .Properties(p => p
                            .Text(t => t.EmployeeInfo.JobRoles.First().RoleName)
                        )
                    )
                )
            )
        )
    ));

---

ObjectProperty jobRolesProperty = new ();
    jobRolesProperty.Properties.Add("roleName", new TextProperty());

    var response = await _client.Indices.CreateAsync<Company>("myindex", c => c
        .Mappings(map => map
            .Properties(
                new Properties<Company>()
                {
                    { "companyName", new TextProperty() },
                    { "employeeInfo", new ObjectProperty()
                    {
                            Properties = new Properties<Employee>()
                            {
                                { "employeeName", new TextProperty() },
                                { "jobRoles", jobRolesProperty }
                            }
                        }
                    }
                }
            )
        )
    );

---

 //Another syntax usage
ObjectProperty jobRolesProperty = new ();
    jobRolesProperty.Properties.Add("roleName", new TextProperty());

        var response = await _client.Indices.CreateAsync<Company>("myindex", c => c
        .Mappings(map => map
            .Properties(p => p
            .Text(t => t.CompanyName)
            .Object(o => o.EmployeeInfo, objConfig => objConfig
                .Properties(
                            new Properties<Employee>()
                            {
                                { "employeeName", new TextProperty() },
                                { "jobRoles", jobRolesProperty }
                            }
                )
            )
        )
    ));

---

The mapping created:

{
"mappings": {
    "properties": {
        "companyName": {
            "type": "text"
        },
        "employeeInfo": {
            "properties": {
                "employeeName": {
                    "type": "text"
                },
                "jobRoles": {
                    "properties": {
                        "roleName": {
                            "type": "text"
                        }
                    },
                    "type": "object"
                }
            },
            "type": "object"
        }
    }
}

}

For managing settings you can check this answer: Elastic Search 8 Defining Analyzers

Impossibly

Sounds great, but how is this an improvement compared to previous versions? – Fancher

I can't comment as to the rationale in changing the library. This was the result of two weeks of implementation and banging my head against the wall until I smashed the correct buttons. Documentation would have been nice, but F12 on classes and reading the github repo ended up providing a solution. – Impossibly

Well, I think having fewer options to achieve the same thing in a library makes sense since this is more maintainable. But Elasticsearch should have provided such an answer as this one in their docs. – Coaptation

Thank you for this answer. Totally helped me out! – Elmoelmore