Installation and setup

To get the latest stable version of the Go client library, run the following:

go get github.com/semi-technologies/weaviate-go-client/v4

This API client is compatible with Go 1.16+.

You can use the client in your Go scripts as follows:

package main

import (
	"context"
	"fmt"
	"github.com/semi-technologies/weaviate-go-client/v4/weaviate"
)

func GetSchema() {
    cfg := weaviate.Config{
        Host:   "localhost:8080",
		Scheme: "http",
    }
    client := weaviate.New(cfg)

    schema, err := client.Schema().Getter().Do(context.Background())
    if err != nil {
        panic(err)
    }
    fmt.Printf("%v", schema)
}

Authentication

Authentication can be added to the configuration of the client as follows:

token := &oauth2.Token{
    AccessToken:  "<token>",
    TokenType:   "Bearer",
}
cfg := weaviate.Config{
    Host:   "weaviate.example.com",
    Scheme: "https",
    ConnectionClient: oauth2.NewClient(context.Background(), oauth2.StaticTokenSource(token)),
}
client := weaviate.New(cfg)

References

All RESTful endpoints and GraphQL functions references covered by the Go client, and explained on those reference pages in the code blocks.

Design

Builder pattern

The Go client functions are designed with a ‘Builder pattern’. A pattern is used to build complex query objects. This means that a function (for example to retrieve data from Weaviate with a request similar to a RESTful GET request, or a more complex GraphQL query) is built with single objects to reduce complexity. Some builder objects are optional, others are required to perform specific functions. All is documented on the RESTful API reference pages and the GraphQL reference pages.

The code snippet above shows a simple query similar to RESTful GET /v1/schema. The client is initiated by requiring the package and connecting to the running instance. Then, a query is constructed by getting the .Schema with .Getter(). The query will be sent with the .Go() function, this object is thus required for every function you want to build and execute.

Migration Guides

From v2 to v4

Unnecessary .Objects() removed from GraphQL.Get()

Before:

client.GraphQL().Get().Objects().WithClassName...

After:

client.GraphQL().Get().WithClassName

GraphQL Get().WithNearVector() uses a builder pattern

In v2 specifying a nearVector argument to client.GraphQL().Get() required passing a string. As a result the user had to know the structure of the GraphQL API. v4 fixes this by using a builder pattern like so:

Before:

client.GraphQL().Get().
  WithNearVector("{vector: [0.1, -0.2, 0.3]}")...

After

nearVector := client.GraphQL().NearVectorArgBuilder().
  WithVector([]float32{0.1, -0.2, 0.3})

client.GraphQL().Get().
  WithNearVector(nearVector)...

All where filters use the same builder

In v2 filters were sometimes specified as strings, sometimes in a structured way. v4 unifies this and makes sure that you can always use the same builder pattern.

GraphQL Get

Before:

// using filter encoded as string
where := `where :{
  operator: Equal
  path: ["id"]
  valueString: "5b6a08ba-1d46-43aa-89cc-8b070790c6f2"
}`

client.GraphQL().Get().
  Objects().
  WithWhere(where)...

// using deprecated graphql arg builder
where := client.GraphQL().WhereArgBuilder().
  WithOperator(graphql.Equal).
  WithPath([]string{"id"}).
  WithValueString("5b6a08ba-1d46-43aa-89cc-8b070790c6f2")

client.GraphQL().Get().
  Objects().
  WithWhere(where)...

After:

where := filters.Where().
  WithPath([]string{"id"}).
  WithOperator(filters.Equal).
  WithValueString("5b6a08ba-1d46-43aa-89cc-8b070790c6f2")

client.GraphQL().Get().
  WithWhere(where)...

GraphQL Aggregate

Before:

where := client.GraphQL().WhereArgBuilder().
  WithPath([]string{"id"}).
  WithOperator(graphql.Equal).
  WithValueString("5b6a08ba-1d46-43aa-89cc-8b070790c6f2")

client.GraphQL().Aggregate().
  Objects().
  WithWhere(where)...

After:

where := filters.Where().
  WithPath([]string{"id"}).
  WithOperator(filters.Equal).
  WithValueString("5b6a08ba-1d46-43aa-89cc-8b070790c6f2")

client.GraphQL().Aggregate().
  WithWhere(where)...

Classification

Before:

valueInt := 100
valueString  := "Government"

sourceWhere := &models.WhereFilter{
  ValueInt: &valueInt,
  Operator: string(graphql.GreaterThan),
  Path:     []string{"wordCount"},
}

targetWhere := &models.WhereFilter{
  ValueString: &valueString,
  Operator:    string(graphql.NotEqual),
  Path:        []string{"name"},
}

client.Classifications().Scheduler().
  WithSourceWhereFilter(sourceWhere).
  WithTargetWhereFilter(targetWhere)...

After:

sourceWhere := filters.Where().
  WithOperator(filters.GreaterThan).
  WithPath([]string{"wordCount"}).
  WithValueInt(100)

targetWhere := filters.Where().
  WithOperator(filters.NotEqual).
  WithPath([]string{"name"}).
  WithValueString("Government")

client.Classifications().Scheduler().
  WithSourceWhereFilter(sourceWhere).
  WithTargetWhereFilter(targetWhere)...

GraphQL Get().WithFields()

In v2 .WithFields() took a GraphQL string that required knowledge of how GraphQL fields are structured. Now this can be done with a variadic function. E.g:

Before:

client.GraphQL.Get().WithClassName("MyClass").WithFields("name price age")...

After:

client.GraphQL.Get().WithClassName("MyClass").
  WithFields(graphql.Field{Name: "name"},graphql.Field{Name: "price"}, graphql.Field{Name: "age"})...

Graphql Get().WithGroup()

In v2 .WithFields() took a GraphQL string that required knowledge of how GraphQL fields are structured. Now this can be done with a builder. E.g:

Before:

client.GraphQL.Get().WithClassName("MyClass")
  .WithGroup("{type:merge force:1.0}")

After:

group := client.GraphQL().GroupArgBuilder()
  .WithType(graphql.Merge).WithForce(1.0)

client.GraphQL.Get().WithClassName("MyClass").WithGroup(group)

Graphql Data().Validator() property renamed

In v2 the naming of the method to specify the Schema was inconsistent with other places in the client. This has been fixed in v4. Rename according to the following:

Before:

client.Data().Validator().WithSchema(properties)

After:

client.Data().Validator().WithProperties(properties)

Change logs

v4.3.0

• Added support for backup API
• Added method WithObjects to ObjectsBatcher
• Added method WithReferences to ReferencesBatcher

v4.2.1

• Fixed fetching db version

v4.2.0

• Added support for class namespaced API calls
• Added support for distance user-facing similarity metric

v4.1.0

• Fix for nearText moveTo and moveAwayFrom parameters
• Fix for where filter operands

v4.0.0

• (Breaking) Remove .Objects() from GraphQL Get(). See migration guide above for details
• (Breaking) GraphQL Aggregate, Explore, and Get: .WithFields() is now a variadic function, see migration guide above
• (Breaking) client.Data().Validator().WithSchema(properties) -> client.Data().Validator().WithProperties(properties)
• (Breaking) GraphQL Get: WithNearVector(nearVector string) -> WithNearVector(nearVector *NearVectorArgumentBuilder). See migration guide above for details

• (Breaking) Where filter: WithWhere(filter string) -> WithWhere(filter *filters.WhereBuilder) See migration guide above

• (Addition) Aggregate support for: nearObject, nearVector, nearText, ask, nearImage, where, objectLimit, limit
• (Addition) Explore support for: nearObject, nearVector, nearText, ask, nearImage, limit, offset
• (Addition) Support for sort in Get GraphQL
• (Addition) Support for indexTimestamps
• (Addition) Batch Delete API support

v3.0.0

• Add builders for where / group / fields
• Support setting stopwords in schema config
• Retrieve and update shard status

v2.3.0

• Added support of the spellcheck module.

v2.2.0

• The new version is compatible with Weaviate v1.4.0 (supports the new img2vec-neural module).

v2.1.x

• Added QnA-transformers module support.

v2.0.x

This change contains breaking changes over previous version as it is aligned with the new API of Weaviate v1. Use the client version v2.0.0 and up for Weaviate instances running v1.0.0 and up. Use client version v1.1.x for Weaviate version 0.23.y. Changes (and migration guide):

• .WithKind() removed

  Due to the removal of semantic Kinds (“things/actions”) in Weaviate, the .WithKind() method is removed on all builders

• .WithSchema() -> .WithProperties()

  Due to the renaming of Object.Schema to Object.Properties in Weaviate, all .WithSchema(propertySchema) methods were renamed to .WithProperties(propertySchema)

• .WithAdditionalInterpretation() => .WithAdditional("interpretation") on ObjectsGetter

  This change reflects two changes in Weaviate: First up, “Underscore Properties” are now called “Additional Properties”, furthermore the presence of such properties may depend on modules and is thus now dynamic. As such, the desired additional property is now passed in as a string.

  Note: There is one exception: .WithVector() can still be used, as the field vector has been “upgraded” from an underscore/additional property to a regular property

• .WithExplore() -> .WithNearText()

  Following the renaming of explore to nearText in Weaviate the builder method was renamed accordingly. Additionally, the new method .WithNearVector("{vector: [...]}") was introduced to allow for nearVector searches.

• .WithK(3) -> .WithSettings(&classification.ParamsKNN{K: &k}) in classification builder

  To reflect the API changes in the classification builder the kNN-specific method .WithK(), was replaced with a more generic .WithSettings(interface{}) which takes any classification type-specific settings, such as &classification.ParamsKNN{K: &k} for kNN or &classification.ParamsContextual{TfidfCutoffPercentile: &value} for text2vec-contextual.

More Resources

If you can’t find the answer to your question here, please look at the:

1. Frequently Asked Questions. Or,
2. Knowledge base of old issues. Or,
3. For questions: Stackoverflow. Or,
4. For issues: Github. Or,
5. Ask your question in the Slack channel: Slack.