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35e5f81bc8
I've found this to be extremely useful. Not that I expect anyone to be able to find this document on their own accord considering the breadth of documentation that we have, this can still be useful for linking to from slack at least (what docs are really for, right?) also the triggers doc stuck out as confusing considering all the triggers stuff going on, I was unable to comprehend how exactly it was helpful other than making people aware that openstack exists and they could build an extension into fn for it if they want to, but this seems true of most things? so, removed it, if anyone objects maybe we could improve it a little?
33 lines
1.8 KiB
Markdown
33 lines
1.8 KiB
Markdown
# Testing a running Fn locally
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Running functions that call other functions in a local testing environment can
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be challenging. This document will outline best practices in functions to make
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this work more easily between deployments as well as some tips to help testing
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locally.
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### Best Practices
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Included in each function invocation will be the request url for how the
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function was invoked, see [formats](../developers/function-format.md) for where exactly,
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this will look something like `request_url` or `FN_REQUEST_URL` depends on the
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format. In FDKs, this will be exposed in the context object for each language.
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If your function invokes other functions, it's recommended to either configure
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the host that your function should use to invoke the other functions yourself
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(by sending it in the payload, or elsewhere), or to parse the `request_url`
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that Fn includes in a function invocation and use that. This makes it easy to
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switch between e.g. `localhost:8080` and `fn.my-company.com`.
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### Configuring functions to invoke locally
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When running functions that call other functions locally, they will need to be
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able to address the fn server to do so. Since functions run in a docker
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container, this can be more challenging when using a `localhost` url. One
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option is to use something more heavyweight like [ngrok](https://ngrok.com/),
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and this will work. It is also possible in a local environment to start `fn`
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with the option `FN_DOCKER_NETWORKS=host`, this is equivalent to running each
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function container with `--net=host`, where each function can address the
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locally running `fn` server to invoke functions against on `localhost`; this
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setting is not recommended for production and any behaviors therein should not
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be expected in production, it is extremely convenient for testing locally
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nonetheless.
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