How to generate clients for different services

[tobiaskahl]

I need clients for multiple services.

duplicating the "generatedJava"-Task does not work, because only each task run is deleting the older ones.
Including multiple schema files will cause duplicate variable names in DgsConstants.kt.

DgsConstants.kt: (112, 17): Conflicting declarations: public object QUERY, public object QUERY

generateJava {
schemaPaths = mutableListOf(
"${rootDir}/academy-service/src/main/resources/graphql/schema.graphqls",
"${rootDir}/user-service/src/main/resources/graphql/schema.graphqls",
)
packageName = "de.example.service.client.graphql"
generateClient = true
}

thanks for some tips

[srinivasankavitha]

Are you able to separate your services into different modules, each with it's own build.gradle file? Then you can define a separate task for each service, which will solve your issue. That is how we address this issue for multiple services in the same project.

[tobiaskahl]

Hi ,
would be possible, but would unnecessarily increase the number of modules.
But thanks for the suggestion of the "workaround", which i may use if i can not fix this.

[srinivasankavitha]

Unless you modify your schema such that codegen can treat all the schema files as part of one schema, i.e. using extend type Query etc., you will have this issue. I'm not sure if that would be correct, but depends on your use case.

[tobiaskahl]

I will try this dirty hack:

doLast { Files.delete(Paths.get("$buildDir/generated/${packageName.replace(".", File.separator)}/DgsConstants.kt")) }

i doesn't know if this file is needed internally. I doesn't need ist for my clients.

[paulbakker]

It's not needed internally.
Generally the recommendation is to put each "client" into a separate module though, because mixing the schemas for multiple clients and/or server doesn't really make sense.

[HeenaChawla21]

I tried creating different tasks in the following way and also deleted the DGSConstants file but it still provides this error :
There are problems with the GraphQL Schema:
* 'Query' type [@5:1] tried to redefine existing 'Query' type [@1:1]
* 'BigDecimal' type [@81:1] tried to redefine existing 'BigDecimal' type [@59:1]

`generateJava {
generateClient = true
schemaPaths = ["****"]
packageName = "folder1"
typeMapping = ["BigDecimal":"java.math.BigDecimal", "Long":"java.lang.Long","DateTime":"java.time.OffsetDateTime"]
includeQueries = [""]

doLast {
    delete files("${project.buildDir.absolutePath}/generated/sources/dgs-codegen/*****/folder1/DgsConstants.java")
}

}
tasks.register("generateCodegen",com.netflix.graphql.dgs.codegen.gradle.GenerateJavaTask) {
packageName = "****folder2"
schemaPaths = [""]
includeQueries = [""]
typeMapping = ["BigDecimal":"java.math.BigDecimal", "Long":"java.lang.Long","DateTime":"java.time.OffsetDateTime"]
generateClient = true

doLast {
    delete files("${project.buildDir.absolutePath}/generated/sources/*****/folder2/DgsConstants.java")
}

}`

[GrantGochnauer]

Hello -

We are running into the same problem.

Consider this scenario:

• We have 2 independently deployed services using DGS with GraphQL schemas
• We have a single application that needs to make calls to both DGS services that have been deployed. Each have their own schema
• In my application, I want to generate all the DGS client code so that I can make calls into each respective service.

I too am running into errors like:

***************************
APPLICATION FAILED TO START
***************************

Description:

There are problems with the GraphQL Schema:
	 * 'Query' type [@1:1] tried to redefine existing 'Query' type [@1:1]
	 * 'Mutation' type [@67:1] tried to redefine existing 'Mutation' type [@72:1]
	 * 'SortBy' type [@209:1] tried to redefine existing 'SortBy' type [@808:1]
	 * 'Audit' type [@218:1] tried to redefine existing 'Audit' type [@734:1]
	 * 'SortableField' type [@228:1] tried to redefine existing 'SortableField' type [@744:1]
	 * 'OrderDirection' type [@237:1] tried to redefine existing 'OrderDirection' type [@749:1]
	 * 'UUID' type [@242:1] tried to redefine existing 'UUID' type [@817:1]
	 * 'JSON' type [@243:1] tried to redefine existing 'JSON' type [@818:1]
	 * 'DateTime' type [@244:1] tried to redefine existing 'DateTime' type [@819:1]
	 * 'Url' type [@245:1] tried to redefine existing 'Url' type [@820:1]
	 * 'Size' type [@247:1] tried to redefine existing directive 'Size' type [@822:1]

We are using Gradle and I have broken out the schema generation into their own gradle sub projects whose only responsibility is to generate the schema. For example:

plugins {
    id 'com.netflix.dgs.codegen' version '6.1.4'
}


tasks.named('generateJava') {
    schemaPaths = ["${projectDir}/src/main/resources/schema/iam"]
    packageName = 'com.xxx.cloud.iam.api' 

    typeMapping = ["Url"               : "java.net.URL",
                   "DateTime"          : "java.time.OffsetDateTime",
                   "JSON"              : "java.util.Map",
                   "Locale"            : "java.util.Locale",
                   "Long"              : "java.lang.Long",
                   "DocumentConnection": "graphql.relay.SimpleListConnection<Document>",
                   "UUID"              : "java.util.UUID"]
}

Then in my main gradle project, I have this:
implementation project(':iam-api-schema') that pulls in my sub project.

However the error is thrown from DgsAutoConfiguration class because it can't instantiate the schema due to the overlapping schema definitions. I should note that each of the sub projects, with their own schemas, use different java packages. I was hoping that by having a different package, DGS would be able to handle schemas at the "package" level instead of being global.

Thoughts?

[GrantGochnauer]

@paulbakker Any thoughts on above - I'm trying to follow the recommendation of using different modules per your suggestion. Thanks!

[GrantGochnauer]

It also seems like DGS is anticipating use of multiple schemas as written in DgsSchemaProvider.kt there is code on line 161 that says:

        var mergedRegistry = if (schema == null) {
            val hasDynamicTypeRegistry = dgsComponents.any { it.annotatedMethods<DgsTypeDefinitionRegistry>().any() }
            val readerBuilder = MultiSourceReader.newMultiSourceReader()
                .trackData(false)
            for (schemaFile in findSchemaFiles(hasDynamicTypeRegistry)) {
                readerBuilder.reader(schemaFile.inputStream.reader(), schemaFile.filename)
                // Add a reader that inserts a newline between schema files to avoid issues when
                // the source files aren't newline-terminated.
                readerBuilder.reader("\n".reader(), "newline")
            }
            SchemaParser().parse(readerBuilder.build())
        } else {
            SchemaParser().parse(schema)
        }

[manjitsinghb]

Here is how we generate clients for 2 sub graphs in the same gradle build file
we had 2 sub graphs and we had conflicting schema names.

tasks.register('subgraph1', com.netflix.graphql.dgs.codegen.gradle.GenerateJavaTask) {
    schemaPaths = ["${projectDir}/src/main/resources/graph/schema/graph1.graphqls"]
    packageName = 'com.project.pojo.graphql1' // The package name to use to generate sources
    typeMapping = [
            "_Any": "java.util.Optional"
    ]
    generateClient = true // Enable generating the type safe query API
}

tasks.register('subgraph2', com.netflix.graphql.dgs.codegen.gradle.GenerateJavaTask) {
    schemaPaths = ["${projectDir}/src/main/resources/graph/schema/graph2.graphqls"]
    packageName = 'com.project.pojo.graphql2 // The package name to use to generate sources
    typeMapping = [
            "_Any": "java.util.Optional"
    ]
    generateClient = true // Enable generating the type safe query API
}

tasks.named("compileJava") {
    dependsOn(tasks.named("subgraph1"))
    dependsOn(tasks.named("subgraph2"))
}

Works as the pojos are generated in different java packages and conflict free