How do I combine multiple OpenAPI specifications into one?

[mraible]

I'm trying to combine three of Zoom's OpenAPI specs into one. I found a possible solution on Stack Overflow. When I try to run the following command, it doesn't work:

java -jar swagger-codegen-cli-3.0.67.jar generate -l openapi -i Meetings.json -i Team\ Chat.json -i Users.json -o . -DoutputFile=Zoom.json

Error is:

10:57:19.129 [main] INFO  i.s.c.v.g.t.AbstractTypeScriptClientCodegen - Template folder: null
10:57:19.130 [main] INFO  i.s.c.v.g.t.AbstractTypeScriptClientCodegen - Template engine: io.swagger.codegen.v3.templates.HandlebarTemplateEngine@588ab592
10:57:19.149 [Thread-0] INFO  i.s.c.v.g.t.AbstractTypeScriptClientCodegen - Template folder: null
10:57:19.150 [Thread-0] INFO  i.s.c.v.g.t.AbstractTypeScriptClientCodegen - Template engine: io.swagger.codegen.v3.templates.HandlebarTemplateEngine@5a2b3f90
10:57:19.327 [Thread-0] INFO  i.s.c.v.i.CodegenIgnoreProcessor - No .swagger-codegen-ignore file found.
Exception in thread "Thread-0" java.lang.RuntimeException: Could not process model 'Update a user'.Please make sure that your schema is correct!
	at io.swagger.codegen.v3.DefaultGenerator.generateModels(DefaultGenerator.java:391)
	at io.swagger.codegen.v3.DefaultGenerator.generate(DefaultGenerator.java:852)
	at io.swagger.codegen.v3.cli.cmd.Generate.run(Generate.java:388)
	at java.base/java.lang.Thread.run(Thread.java:1583)
Caused by: java.lang.ClassCastException: class java.lang.Long cannot be cast to class java.lang.Integer (java.lang.Long and java.lang.Integer are in module java.base of loader 'bootstrap')
	at io.swagger.codegen.v3.generators.DefaultCodegenConfig.processPropertySchemaTypes(DefaultCodegenConfig.java:1671)
	at io.swagger.codegen.v3.generators.DefaultCodegenConfig.fromProperty(DefaultCodegenConfig.java:1592)
	at io.swagger.codegen.v3.generators.DefaultCodegenConfig.addVars(DefaultCodegenConfig.java:3181)
	at io.swagger.codegen.v3.generators.DefaultCodegenConfig.addVars(DefaultCodegenConfig.java:3151)
	at io.swagger.codegen.v3.generators.DefaultCodegenConfig.addVars(DefaultCodegenConfig.java:3139)
	at io.swagger.codegen.v3.generators.DefaultCodegenConfig.fromModel(DefaultCodegenConfig.java:1479)
	at io.swagger.codegen.v3.DefaultGenerator.processModels(DefaultGenerator.java:1128)
	at io.swagger.codegen.v3.DefaultGenerator.generateModels(DefaultGenerator.java:380)
	... 3 more

My Java version is as follows:

$ java --version
openjdk 21.0.4 2024-07-16 LTS
OpenJDK Runtime Environment Temurin-21.0.4+7 (build 21.0.4+7-LTS)
OpenJDK 64-Bit Server VM Temurin-21.0.4+7 (build 21.0.4+7-LTS, mixed mode)

[mraible]

If I remove -i Users.json from my command, it works. However, it doesn't seem to combine the files. The outputFile only contains the paths from Team Chat.json.

If I try using a comma-delimited list of files, it fails:

11:09:16.742 [Thread-0] ERROR i.s.c.v3.config.CodegenConfigurator - Unable to read URL: Meetings.json,Team Chat.json
java.lang.RuntimeException: Could not find Meetings.json,Team Chat.json on the classpath

[mraible]

I was able to solve this using openapi-merge-cli and an openapi-merge.json file:

{
  "inputs": [
    {
      "inputFile": "./Meetings.json"
    },
    {
      "inputFile": "./Team Chat.json"
    },
    {
      "inputFile": "./Users.json"
    }
  ],
  "output": "./Zoom.json"
}

$ npx openapi-merge-cli

## Loaded the configuration: 3 inputs (+29ms)
## Loading input 0: Meetings.json (+0ms)
## Loading input 1: Team Chat.json (+0ms)
## Loading input 2: Users.json (+0ms)
## Loaded the inputs into memory, merging the results. (+12ms)
## Inputs merged, writing the results out to 'Zoom.json' (+32ms)
## Finished writing to 'Zoom.json' (+10ms)