This allows configuring the daemon's proxy server through the daemon.json con-
figuration file or command-line flags configuration file, in addition to the
existing option (through environment variables).
Configuring environment variables on Windows to configure a service is more
complicated than on Linux, and adding alternatives for this to the daemon con-
figuration makes the configuration more transparent and easier to use.
The configuration as set through command-line flags or through the daemon.json
configuration file takes precedence over env-vars in the daemon's environment,
which allows the daemon to use a different proxy. If both command-line flags
and a daemon.json configuration option is set, an error is produced when starting
the daemon.
Note that this configuration is not "live reloadable" due to Golang's use of
`sync.Once()` for proxy configuration, which means that changing the proxy
configuration requires a restart of the daemon (reload / SIGHUP will not update
the configuration.
With this patch:
cat /etc/docker/daemon.json
{
"http-proxy": "http://proxytest.example.com:80",
"https-proxy": "https://proxytest.example.com:443"
}
docker pull busybox
Using default tag: latest
Error response from daemon: Get "https://registry-1.docker.io/v2/": proxyconnect tcp: dial tcp: lookup proxytest.example.com on 127.0.0.11:53: no such host
docker build .
Sending build context to Docker daemon 89.28MB
Step 1/3 : FROM golang:1.16-alpine AS base
Get "https://registry-1.docker.io/v2/": proxyconnect tcp: dial tcp: lookup proxytest.example.com on 127.0.0.11:53: no such host
Integration tests were added to test the behavior:
- verify that the configuration through all means are used (env-var,
command-line flags, damon.json), and used in the expected order of
preference.
- verify that conflicting options produce an error.
Signed-off-by: Anca Iordache <anca.iordache@docker.com>
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
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