[k6] OpenAPI code generator for k6 API load-testing tool (ES5.1+)

[mostafa]

k6 is an API load-testing tool created by Load Impact AB to help developers and DevOps people test the performance of their APIs. It is written in Go, and is scriptable in JavaScript, supporting ES5.1+. At Load Impact, we have converters/codegens for HAR files, Postman collections and JMeter to help users of k6 easily be onboard to our tool.

Since we focus on API load-testing, we thought it would be a good idea to create a Swagger/OpenAPI code generator, too. So, after much research, we found that this project is the officially developed and maintained one that we can reliably put our efforts on. Thus we created this code generator, to help generate k6 scripts from Swagger 2.0 specification documents.

This is our first PoC and we definitely would like to hear your feedback to improve it further. There are some questions for the official maintainers:

1. Should we also edit the README.md and add ourselves as Template Creators and Technical Committee for k6?
2. Does our implementation seem like a good starting point for further improving the project?

We really appreciate your feedback on this.
Note: On @wing328's suggestion I have ported the code from swagger-api/swagger-codegen#10013 to this project.

PR checklist

• Read the contribution guidelines.
• If contributing template-only or documentation-only changes which will change sample output, build the project before.
• Run the shell script(s) under ./bin/ (or Windows batch scripts under.\bin\windows) to update Petstore samples related to your fix. This is important, as CI jobs will verify all generator outputs of your HEAD commit, and these must match the expectations made by your contribution. You only need to run ./bin/{LANG}-petstore.sh, ./bin/openapi3/{LANG}-petstore.sh if updating the code or mustache templates for a language ({LANG}) (e.g. php, ruby, python, etc).
• File the PR against the correct branch: master, 4.3.x, 5.0.x. Default: master.
• Copy the technical committee to review the pull request if your PR is targeting a particular programming language.

[wing328]

@mostafa Thanks for the PR. I notice some build errors. I'll try to update your branch directly to fix those issues.

[wing328]

I don't have right to push to your branch. Please apply the following fix when you've time:

diff --git a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/k6Codegen.java b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/k6Codegen.java
index 72d9ac2edc..a220b67d32 100644
--- a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/k6Codegen.java
+++ b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/k6Codegen.java
@@ -334,7 +334,7 @@ public class k6Codegen extends DefaultCodegen implements CodegenConfig {
                                     "http.file(open(\"/path/to/file.bin\", \"b\"), \"test.bin\")");
                         } else {
                             k6Parameter = new Parameter(parameter.paramName, !reference.isEmpty() ? reference
-                                    : getDoubleQuotedString(parameter.dataType.toLowerCase()));
+                                    : getDoubleQuotedString(parameter.dataType.toLowerCase(Locale.ROOT)));
                         }
 
                         bodyOrFormParams.add(k6Parameter);
@@ -349,13 +349,13 @@ public class k6Codegen extends DefaultCodegen implements CodegenConfig {
                         switch (parameter.getIn()) {
                             case "header":
                                 httpParams.add(new Parameter(parameter.getName(), getTemplateString(parameter.getName())));
-                                extraParameters.add(new Parameter(parameter.getName(), parameter.getName().toUpperCase()));
+                                extraParameters.add(new Parameter(parameter.getName(), parameter.getName().toUpperCase(Locale.ROOT)));
                                 break;
                             case "path":
                             case "query":
                                 if (parameter.getIn().equals("query"))
                                     queryParams.add(new Parameter(parameter.getName(), getVariable(parameter.getName())));
-                                variables.add(new Parameter(parameter.getName(), parameter.getName().toUpperCase()));
+                                variables.add(new Parameter(parameter.getName(), parameter.getName().toUpperCase(Locale.ROOT)));
                                 break;
                             default:
                                 break;
@@ -407,7 +407,7 @@ public class k6Codegen extends DefaultCodegen implements CodegenConfig {
         StringBuilder reference = new StringBuilder();
         int modelEntrySetSize = model.getAllVars().size();
         for (CodegenProperty property : model.getAllVars()) {
-            reference.append(getDoubleQuotedString(property.name)).append(": ").append(getDoubleQuotedString(property.dataType.toLowerCase()));
+            reference.append(getDoubleQuotedString(property.name)).append(": ").append(getDoubleQuotedString(property.dataType.toLowerCase(Locale.ROOT)));
             if (modelEntrySetSize > 1)
                 reference.append(", ");
         }
@@ -430,7 +430,7 @@ public class k6Codegen extends DefaultCodegen implements CodegenConfig {
 
     /**
      * Concatenates an array of path segments into a path string.
-     * 
+     *
      * @param segments The path segments to concatenate. A segment may contain
      *                 either of the file separator characters '\' or '/'. A segment
      *                 is ignored if it is <code>null</code>, empty or

[wing328]

Should we also edit the README.md and add ourselves as Template Creators and Technical Committee for k6?

I'll do that in a separate PR.

Does our implementation seem like a good starting point for further improving the project?

I think so. I'll consider it as a beta release so as to gather feedback from the community.

[wing328]

The CircleCI failed due to outdated documentation. I'll push a fix (commit) after merging this PR.

I'll also file a PR with various improvements to this new generator.