Table of Contents

Connecting

This page contains the information you need to create an instance of the Qdrant gRPC .NET client, to connect to your Qdrant cluster.

The client is thread safe, so create a single instance and reuse it for the lifetime of the application.

Simple configuration

To connect to a locally running cluster

var channel = QdrantChannel.ForAddress("http://localhost:6334");
var client = new QdrantGrpcClient(channel);

Setting an API key

When your Qdrant cluster is secured by API key based authentication, a client can be configured with an API to use as follows

var channel = QdrantChannel.ForAddress("http://localhost:6334", new ClientConfiguration
{
    ApiKey = "<api key>"
});
var client = new QdrantGrpcClient(channel);

where <api key> is the API key defined in the Qdrant cluster configuration.

Validating self-signed TLS certificates

When using API key based authentication, it is strongly recommended to also secure the cluster with Transport Layer Security (TLS) for encrypted communications.

If the Qdrant cluster is secured with a certificate that is signed by a trusted Certificate Authority (CA), no further action needs to be taken; the certificate will be validated by default. A trusted CA is one that is trusted by the operating system on which the client is running, which typically means that the CA certificate is in the certificate/truststore of the operating system.

Often, self-signed certificates are used to secure self-hosted clusters, where certificates are generated by your own CA. The client can be configured to validate the SHA-256 certificate thumbprint/fingerprint of the certificate

var channel = QdrantChannel.ForAddress("https://localhost:6334", new ClientConfiguration
{
    ApiKey = "<api key>",
    CertificateThumbprint = "<certificate thumbprint>"
});
var client = new QdrantGrpcClient(channel);

where <certificate thumbprint> is the SHA-256 certificate thumbprint of the certificate or CA certificate. The thumbprint of a certificate can be retrieved at any time with

Using openssl

openssl x509 -in cert.pem -fingerprint -sha256 -noout

where cert.pem is the path to the certificate.

This outputs the thumbprint/fingerprint similar to

SHA256 Fingerprint=28:FB:5A:5E:F7:62:23:8E:C2:59:AE:46:72:01:80:B8:55:BE:32:74:FF:39:A9:ED:C1:B4:65:A5:B4:6A:45:46

The client handles differences in output format, so you can copy and paste the thumbprint verbatim.

Advanced Client configuration

QdrantChannel is a convenient way to configure a gRPC channel for the client. If you're in need of more control over client configuration, you are free to use GrpcChannel directly. For example

var channel = GrpcChannel.ForAddress("https://localhost:6334", new GrpcChannelOptions
{
    MaxRetryAttempts = 2,
    MaxReceiveMessageSize = 8_388_608, // 8MB
    HttpHandler = new HttpClientHandler
    {
        ServerCertificateCustomValidationCallback =
            CertificateValidation.Thumbprint("<certificate thumbprint>")
    }
});
var callInvoker = channel.Intercept(metadata =>
{
    metadata.Add("api-key", "<api key>");
    return metadata;
});
var client = new QdrantGrpcClient(callInvoker);

This configures the client for API key based authentication and TLS certificate thumbprint validation, in addition to applying some other settings.

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