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This interface layer implements the basic form of the `http` interface protocol,
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which is used for things such as reverse-proxies, load-balanced servers, REST
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service discovery, et cetera.
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By providing the `http` interface, your charm is providing an HTTP server that
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can be load-balanced, reverse-proxied, used as a REST endpoint, etc.
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Your charm need only provide the port on which it is serving its content, as
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soon as the `{relation_name}.available` state is set:
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@when('website.available')
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def configure_website(website):
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website.configure(port=hookenv.config('port'))
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By requiring the `http` interface, your charm is consuming one or more HTTP
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servers, as a REST endpoint, to load-balance a set of servers, etc.
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Your charm should respond to the `{relation_name}.available` state, which
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indicates that there is at least one HTTP server connected.
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The `services()` method returns a list of available HTTP services and their
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associated hosts and ports.
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The return value is a list of dicts of the following form:
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'service_name': name_of_service,
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'hostname': address_of_host,
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'port': port_for_host,
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A trivial example of handling this interface would be:
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from charms.reactive.helpers import data_changed
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@when('reverseproxy.available')
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def update_reverse_proxy_config(reverseproxy):
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services = reverseproxy.services()
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if not data_changed('reverseproxy.services', services):
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for service in services:
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for host in service['hosts']:
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hookenv.log('{} has a unit {}:{}'.format(
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services['service_name'],
added
removed
deps/interface/interface-http/README.md
