Gitlab report builder

We'd like to get a project-report we can send to our customers weekly. Gitlab has an API which makes it possible to get almost anything out of it, and there are solutions like mPDF to create a PDF from HTML. We "only" need to combine the API with a PDF-generator (and some details). The exact contents of the report will be different per project, thus the template should be built up with (almost) all API-calls being available. This means that things like {{Gitlab->Project->Name}} should be possible. The API probably has to be enriched and thus extra variables are to be created - as of now this only has to be facilitated in the design. A web-app should handle the report-generation. The first step must be fully automated, where data is gathered from Gitlab for the selected project. The second step is to add text to specific places via the webapp, where the rest of the report is already previewed. The third step is saving the generated html-file, produce the PDF and offer the PDF for download. Important: manual edits should be able by calling the PDF-generation from the command line on the edited html-file. The tool should be written in a web-language and the code should be clean. For PDF-generation mPDF was suggested to us, but we're all ears for a better library. The whole thing should run in a docker. See [login to view URL] for when PHP is chosen. Bonus is for producing line-graphs. Security is by using gitlab's authentication or LDAP or Docker-config to only allow local usage.