RPC backend implementation

[rajarshimaitra]

Description

This opens the RPC backend recently added in BDK bitcoindevkit/bdk#407.

This builds on top of BDK master, because RPC back end isn't released yet.

I committed the Cargo.lock file too understanding that we are suppose to commit this file also as per #27 (comment). Let me know if that's not appropriate.

This is now ready for review.

Notes to the reviewers

It seems there is some failure with esplora backend, probably something related to recent restructuring of esplora module in
bdk. Now that there are two different esplora configuration in BDK, we need to either chose one for bdk-cli, or have both options
as feature flag. I decided to go for use-explora-reqwest for now.

But in any case this error should not be there, as I can see bdk compiles with maybe-await!() macro in master just fine, with the reqwest esplora feature. Not sure what is the issue here. Any suggestion would be helpful.

Compiling bdk-cli v0.2.1-dev (/home/raj/github-repo/bdk-cli)
error[E0277]: the `?` operator can only be applied to values that implement `Try`
   --> src/lib.rs:984:13
    |
984 |             maybe_await!(wallet.sync(log_progress(), max_addresses))?;
    |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the `?` operator cannot be applied to type `impl Future`
    |
    = help: the trait `Try` is not implemented for `impl Future`
    = note: required by `into_result`

error[E0277]: the `?` operator can only be applied to values that implement `Try`
   --> src/lib.rs:999:24
    |
999 |             let txid = maybe_await!(wallet.broadcast(tx))?;
    |                        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the `?` operator cannot be applied to type `impl Future`
    |
    = help: the trait `Try` is not implemented for `impl Future`
    = note: required by `into_result`

This is causing the test failures.

Checklists

All Submissions:

• I've signed all my commits
• I followed the contribution guidelines
• I ran cargo fmt and cargo clippy before committing

New Features:

• I've added tests for the new feature
• I've added docs for the new feature
• I've updated CHANGELOG.md

[rajarshimaitra]

Updated with v0.10.0. But cargo build --features esplora still fails.

[rajarshimaitra]

The above error is fixed (along with other updates for BDK v0.10.0) in https://github.com/bitcoindevkit/bdk-cli/pulls

Decided to use esplora ureq version. Removing all async from bdk-cli. cc @tcharding @notmandatory

This should be merged after the version update PR.

[rajarshimaitra]

Rebased on esplora fix at #41 .. This should be merged after that PR.

[rajarshimaitra]

Rebased on master.

[rajarshimaitra]

There needs to be readme update after this. But doing it in this PR might cause conflicts with #44.

So putting that for a separate PR.

[notmandatory]

Please add rpc to the build.rs logic that prevents two blockchain features from being enabled together. Also maybe another rebase and then you can mention it as an option in the README too. I'd like to merge this one next, then #42. Thanks!

[notmandatory]

Need to add feature = "rpc" also in src/lib.rs line 167

[rajarshimaitra]

• Rebased,
• updated build script,
• fixed in lib.rs,
• Updated Readme

[notmandatory]

ACK 32a3a55

Looks good, thanks for the update. I'll give anyone else interested a chance to review and if no objections merge tomorrow.