Gergő Jedlicska
38 lines
1.7 KiB
Markdown
38 lines
1.7 KiB
Markdown
# PreviewService
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This component generates object previews for Speckle Objects.
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It reads preview tasks from the DB and uses Puppeteer and an internal Viewer to generate previews, which are currently stored in the DB.
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This is an overview of this service:
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## Run locally
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With an updated viewer installed in the current directory, you should first build the frontend-part of the preview service: The simple webpage with the viewer that will be accessed with Puppeteer to generate the preview:
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```
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yarn build
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```
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This should be rerun whenever you make changes to the viewer (if you make local viewer changes, don't forget to build the viewer module before running this)
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After the viewer web page is up to date, run the preview service with:
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```
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yarn dev
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```
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This will use the default dev DB connection of `postgres://speckle:speckle@127.0.0.1/speckle`. You can pass the environment variable `PG_CONNECTION_STRING` to change this to a different DB.
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## Deployment notes
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When deploying the PreviewService, it's important to pay attention to the memory requirements: Speckle streams can be arbitrarily large and the preview service must load the entire stream in order to generate the preview image.
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You must limit the PreviewService container memory to a value that you want to allocate for preview generation. If a stream requires more memory then the limit, the preview for that stream will fail, but the entire system remains stable.
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To limit the container memory when running with `docker run`, you can use the `-m` flag.
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With docker-compose, you must use a docker-compose file at version 2 (not 3) and use the `mem_limit` option.
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