[BUG] Can't generate only one specific endpoint of API

[altrof]

🐛 Bug Report:

Describe the bug

I decided migrate to OpenAPI Generator from Swagger Codegen.
In Swagger Codegen was possible generate specific endpoint of API by providing operationId with separator '#':
"apis": "ContractSearch#findContractByCustomerId"

So here is my Gradle task and setup for OpenAPI Generator:

def openApiGeneratorConfig = {
    classpath configurations.openApiGenerator
    systemProperties = ["apis": "", "models": ""]
    mainClass = 'org.openapitools.codegen.OpenAPIGenerator'
    args 'generate'
    args '-o', "$rootDir/external"
    args '-t', "$rootDir/external/src/main/resources/codegen/templates/"
    args '--skip-validate-spec'
    args "--import-mappings", "Instant=java.time.Instant,YearMonth=java.time.YearMonth,LocalDateTime=java.time.LocalDateTime"
    args "--type-mappings", "double=BigDecimal"
}

def configFilesRoute = "$rootDir/external/src/main/resources/config/swagger"

task generateExternalApiClient(type: JavaExec) {
    configure openApiGeneratorConfig
    systemProperties = ["apis": "ContractSearch#findContractByCustomerId"]
    args "-i", "http://localhost:9901/v2/api-docs"
    args "-c", "$configFilesRoute/loan.json"
}

Expected behavior

Generate only one specified endpoint. But in OpenAPI Generator it doesn't work. Only if whole api "apis": "ContractSearch", then it will generate.

Package System (versions):

• OpenAPI Generator 6.6.0
• Java 17
• Spring Boot 2.7

Also I wrote question on stackoverflow:
https://stackoverflow.com/questions/77557530/openapi-generator-generate-only-one-specific-endpoint-from-api

Maybe it is not a bug, just doesn't have this functionality.

[wing328]

so your goal is to generate the output (client, server, etc) using just one operation (based on operationId) in the openapi doc/spec, right?

[altrof]

yes, absolutely right. e.g. controller CustomerApi has many endpoints and I want to generate in the another service only one CustomerApi endpoint /create-customer-relation.
In swagger it was possible: CustomerApi#createCustomerRelation, because in CustomerApi it has annotation @ApiOperation with nickname = "createCustomerRelation", which convert into operationId
Hope that you understand my goal. :)

[wing328]

we don't offer that at the moment.

may I know if you've time to contribute this enhancement or sponsor this feature financially?

[altrof]

Yes, I can try to create this feature (contribute).
Will create issue, if the similar is didn't yet create.

[wing328]

can you please PM me via Slack to further discuss this when you've time?

https://join.slack.com/t/openapi-generator/shared_invite/zt-12jxxd7p2-XUeQM~4pzsU9x~eGLQqX2g

[wing328]

i've filed #17859 to add a new rule called FILTER with a list of operationId as the input.

my local tests look good so far.

can you also give it a try when you've time?

[wing328]

PR merged. please give it a try with the latest master.

[orolhawion]

The same would be very useful to use with tags. I tried FILTER=tags:desired|api but it did not work. The use case is, I have one large openApi.yaml with many endpoints categorized with tags. I only need a client and/or server for endpoints that have specific tags.

[altrof]

I also thought about it and did it with tricky way in gradle:

gradle closure:

def addApiArgs(String... apisWithEndpoints) {
    def apis = []
    def endpointFilters = []

    apisWithEndpoints.each { apiWithEndpoints ->
        def (api, endpoints) = apiWithEndpoints.split('#')
        apis << api
        endpointFilters.addAll(endpoints.split('\\|').collect { "$it" })
    }

    return ["--global-property", "apis=${apis.join(':')}", "--openapi-normalizer", "FILTER=operationId:${endpointFilters.join('|')}"]
}

gradle tasks:

tasks.register('generateReportingApiClient', JavaExec) {
    configure openApiGeneratorConfig
    args '-i', 'https://reporting-finance-dev.local/api-docs'
    args '-c', "$configFilesRoute/reporting.json"

    args addApiArgs("Reporting#generateReportsForDate|sync|runChangeSystemDate")
}

[orolhawion]

I am afraid I cannot do this with maven.

[altrof]

ChatGPT:

Add the OpenAPI Generator Plugin to your pom.xml

<build>
    <plugins>
        <plugin>
            <groupId>org.openapitools</groupId>
            <artifactId>openapi-generator-maven-plugin</artifactId>
            <version>5.1.1</version>
            <executions>
                <execution>
                    <goals>
                        <goal>generate</goal>
                    </goals>
                </execution>
            </executions>
            <configuration>
                <inputSpec>https://reporting-finance-dev.local/api-docs</inputSpec>
                <configFile>${project.basedir}/config/reporting.json</configFile>
                <globalProperties>
                    <apis>${apis}</apis>
                    <openapiNormalizer>FILTER=operationId:${endpoints}</openapiNormalizer>
                </globalProperties>
            </configuration>
        </plugin>
    </plugins>
</build>

Define Profiles to Configure the API and Endpoints

<profiles>
    <profile>
        <id>generate-reporting-api-client</id>
        <properties>
            <apis>Reporting</apis>
            <endpoints>generateReportsForDate|sync|runChangeSystemDate</endpoints>
        </properties>
        <build>
            <plugins>
                <plugin>
                    <groupId>org.openapitools</groupId>
                    <artifactId>openapi-generator-maven-plugin</artifactId>
                    <executions>
                        <execution>
                            <id>generate-client</id>
                            <goals>
                                <goal>generate</goal>
                            </goals>
                            <configuration>
                                <inputSpec>https://reporting-finance-dev.local/api-docs</inputSpec>
                                <configFile>${project.basedir}/config/reporting.json</configFile>
                                <globalProperties>
                                    <apis>${apis}</apis>
                                    <openapiNormalizer>FILTER=operationId:${endpoints}</openapiNormalizer>
                                </globalProperties>
                            </configuration>
                        </execution>
                    </executions>
                </plugin>
            </plugins>
        </build>
    </profile>
</profiles>

maybe it will be work :D