Add build instructions for the http bridge in CI

[KtorZ]

Issue Number

#5

Overview

• I have extended our CI configuration to build the cardano-http-bridge and make it available in scope for testing
• I have made sure that the build artifacts are cached between jobs

Comments

The http-bridge is now built within the "Compiling" job, before the Haskell code -- if not already present (so, only on the first run).

Before tests run, we now do a cardano-http-bridge --help which resolves correctly and proves that the bridge is available in scope for testing.

[rvl]

Suggested change

	# Do not choose a language; we provide our own build tools:
	# Use the Travis Rust build tools for cardano-http-bridge.
	# Provide our own Haskell build tools for cardano-wallet.

[KtorZ]

Good catch 👍

[paweljakubas]

so why Tests on CI has failed?

[KtorZ]

This is what I am trying to figure out. I made another round of testing yesterday, completely clearing the cache, and it seems that I broke something 🤔 ... Will figure it out..

[paweljakubas]

that's strange :

== Section test:unit ==
Missing other-modules entry
* Cardano.Wallet.BlockSyncerSpec
Redundant build-depends entry
* time-units

There is no Cardano.Wallet.BlockSyncerSpec in the unit section because there is not this module anymore. Moreover, time-units is needed in test/unit/Cardano/NetworkLayerSpec.hs as there is import there in line 29:

import Data.Time.Units

There is some caching problem out there as @KtorZ underlined

[KtorZ]

Ok, I figured. We can't actually have two parallels jobs which share the same cache. I hoped Travis would be "smart enough" to merge the cache when there are uploads to the cache from different sources, but it doesn't. So, the job building the http bridge was finishing first, uploading his cache and then, got overwritten by the job that compiles the haskell sources.

In the next stage, only the latter cache was available, which doesn't contain the cardano-http-bridge. So I've moved the instruction to build the http-bridge inside the "compiling" job. In the end, it takes a couple of milliseconds if the bridge has already been built and is already in cache, otherwise, it will built it within 10 minutes and cache it afterwards.

Since there's now only job uploading to the cache, no more race-condition and cache overwriting.