Set defaults for backend creation

[Integralist]

We want to avoid this situation where we have to set the flags to the same value:

fastly backend create --name=example --address=example.com --override-host=example.com --ssl-cert-hostname=example.com --ssl-sni-hostname=example.com

Instead it would better if the user could just set:

fastly backend create --name=example --address=example.com

NOTE: I went back and updated the compute deploy logic so it included ssl-cert-hostname as we were only handling override-host and ssl-sni-hostname.

Examples

1. Allow empty values
2. Allow individual values
3. Ensure sensible defaults
4. Validate IP address behaviour

1. Allow empty values

If user sets the flags (--override-host, --ssl-cert-hostname, --ssl-sni-hostname) with an empty string, then let those values be used.

$ fastly backend create --name allow_empty --address example.com --override-host "" --ssl-cert-hostname "" --ssl-sni-hostname "" --service-id ... --version latest
$ fastly backend list --service-id ... --version latest --verbose

                Name: allow_empty
                Comment:
                Address: example.com
                Port: 80
                Override host:
                Connect timeout: 1000
                Max connections: 200
                First byte timeout: 15000
                Between bytes timeout: 10000
                Auto loadbalance: false
                Weight: 100
                Healthcheck:
                Shield:
                Use SSL: false
                SSL check cert: false
                SSL CA cert:
                SSL client cert:
                SSL client key:
                SSL cert hostname:
                SSL SNI hostname:
                Min TLS version:
                Max TLS version:
                SSL ciphers:

2. Allow individual values

If user sets the flags (--override-host, --ssl-cert-hostname, --ssl-sni-hostname) with unique values, then let those values be used.

$ fastly backend create --name allow_individual --address example.com --override-host "example-one.com" --ssl-cert-hostname "example-two.com" --ssl-sni-hostname "example-three.com" --service-id ... --version latest
$ fastly backend list --service-id ... --version latest --verbose

                Name: allow_individual
                Comment:
                Address: example.com
                Port: 80
                Override host: example-one.com
                Connect timeout: 1000
                Max connections: 200
                First byte timeout: 15000
                Between bytes timeout: 10000
                Auto loadbalance: false
                Weight: 100
                Healthcheck:
                Shield:
                Use SSL: false
                SSL check cert: false
                SSL CA cert:
                SSL client cert:
                SSL client key:
                SSL cert hostname: example-two.com
                SSL SNI hostname: example-three.com
                Min TLS version:
                Max TLS version:
                SSL ciphers:

3. Ensure sensible defaults

If user omits all three flags (--override-host, --ssl-cert-hostname, --ssl-sni-hostname) and if --address is a hostname, then set all three field values to the hostname given in the --address flag.

$ fastly backend create --name ensure_sensible_defaults --address example.com --service-id ... --version latest
$ fastly backend list --service-id ... --version latest --verbose

                Name: ensure_sensible_defaults
                Comment:
                Address: example.com
                Port: 80
                Override host: example.com
                Connect timeout: 1000
                Max connections: 200
                First byte timeout: 15000
                Between bytes timeout: 10000
                Auto loadbalance: false
                Weight: 100
                Healthcheck:
                Shield:
                Use SSL: false
                SSL check cert: false
                SSL CA cert:
                SSL client cert:
                SSL client key:
                SSL cert hostname: example.com
                SSL SNI hostname: example.com
                Min TLS version:
                Max TLS version:
                SSL ciphers:

4. Validate IP address behaviour

If user omits all three flags (--override-host, --ssl-cert-hostname, --ssl-sni-hostname) and if --address is an IP, then don't set a value for any of the field values.

$ fastly backend create --name validate_ip_address --address 8.8.8.8 --service-id ... --version latest
$ fastly backend list --service-id ... --version latest --verbose

                Name: validate_ip_address_behaviour
                Comment:
                Address: 8.8.8.8
                Port: 80
                Override host:
                Connect timeout: 1000
                Max connections: 200
                First byte timeout: 15000
                Between bytes timeout: 10000
                Auto loadbalance: false
                Weight: 100
                Healthcheck:
                Shield:
                Use SSL: false
                SSL check cert: false
                SSL CA cert:
                SSL client cert:
                SSL client key:
                SSL cert hostname:
                SSL SNI hostname:
                Min TLS version:
                Max TLS version:
                SSL ciphers: