Check_MK Werk 6920: HTTP proxies can now be configured globally

ID: 6920 Title: HTTP proxies can now be configured globally Component: Core & setup Level: 2 Class: New feature Version: 1.6.0i1 To enable components to connect to external resources in proxied networks more easily it is now possible to configure several HTTP proxies using the global setting "HTTP proxies". Imagine a scenario where your monitoring server is located in your company internal network and you need to make a connection to a external HTTP server in the internet while you can only connect to this server using a proxy server. In the past the most spread option is to set the HTTP(S)_PROXY environment variables for such a call and hope that the program you use for the connection supports these envrionment variables. Now it is possible to configure the proxies using the GUI in a central place and refer to these settings from different parts of your configuration. These proxies will be usable by e.g. special agents, notification scripts and active checks, which need to use a proxy for their work. As example the pushover notification script has been migrated to support the global proxy settings. Note to notification script developers: You have to name the notification proxy element of the Dictionary parameters valuespec "proxy_url" to make it work as expected with globally configured proxies. Note to special agent and active check developers: There is a new function available get_http_proxy(http_proxy). Pass the "http_proxy" value a user configured using the HTTPProxyReference valuespec to this function an you will get back the proxy URL as string or None in case no proxy should be set via command line (see "pydoc cmk_base.check_api.get_http_proxy_for_cmdline" for further information). CMK-1407