Clap based improvements for the CLI

[hu55a1n1]

Summary

• Reuse code by grouping related fields into a single struct and flattening it in the parent struct (see feat(dcap): make DCAP RA default  #150 (comment))
• Try to use clap groups for imposing group constraints w.r.t. mock-sgx for example. (see feat(dcap): make DCAP RA default  #150 (comment))

(Copying @dangush's comments from #150)

[piotr-roslaniec]

We have no access to the mock_sgx field present in the "higher contexts" where SgxConfiguration is used, so we have to rely on the MOCK_SGX environment variable directly. Using ArgGroup seems a bit superfluous here. We still need to condition fields based on the reverse logic of the MOCK_SGX environment variable. Please clarify if I misunderstood, otherwise I'd be happy to contribute:

/// SGX-specific configuration. Required if `MOCK_SGX` is not set.
#[derive(Debug, Parser, Clone, Serialize, Deserialize)]
pub struct SgxConfiguration {
    /// FMSPC (Family-Model-Stepping-Platform-Custom SKU)
    #[arg(long)]
    #[serde(skip_serializing_if = "Option::is_none")]
    pub fmspc: Option<Fmspc>,

    /// Address of the TcbInfo contract
    #[arg(long)]
    #[serde(skip_serializing_if = "Option::is_none")]
    pub tcbinfo_contract: Option<AccountId>,

    /// Address of the DCAP verifier contract
    #[arg(long)]
    #[serde(skip_serializing_if = "Option::is_none")]
    pub dcap_verifier_contract: Option<AccountId>,
}

impl SgxConfiguration {
    fn validate(&self) -> Result<(), String> {
        if std::env::var("MOCK_SGX").is_err() {
            self.check_required_field(&self.fmspc, "FMSPC")?;
            self.check_required_field(&self.tcbinfo_contract, "tcbinfo_contract")?;
            self.check_required_field(&self.dcap_verifier_contract, "dcap_verifier_contract")?;
        }
        Ok(())
    }

    fn check_required_field<T>(&self, field: &Option<T>, field_name: &str) -> Result<(), String> {
        if field.is_none() {
            return Err(format!("{} is required if MOCK_SGX isn't set", field_name));
        }
        Ok(())
    }
}

[dusterbloom]

@piotr-roslaniec Thanks for you comment. I am not 100% clear on what you meant.
I have tried to imagine what you meant and built a quick test branch.
Can you please give it a look it out and/or just try it out?

[piotr-roslaniec]

Hi @dusterbloom, thanks for getting back to me. For details, please see this draft: #279