Add 'spago freeze' to compute hashes on the package set (purescript#113)

README.md

@@ -26,6 +26,7 @@ PureScript package manager and build tool powered by [Dhall][dhall] and
  - [Adding and overriding dependencies in the Package Set](#adding-and-overriding-dependencies-in-the-package-set)
  - [Verifying your additions and overrides](#verifying-your-additions-and-overrides)
  - [Upgrading the Package Set](#upgrading-the-package-set)
+ - [Caching the Package Set](#caching-the-package-set)
  - [Building, bundling and testing a project](#building-bundling-and-testing-a-project)
 - [FAQ](#faq)
  - [Hey wait we have a perfectly functional `pulp` right?](#hey-wait-we-have-a-perfectly-functional-pulp-right)
@@ -351,6 +352,32 @@ Fetching the new one and generating hashes.. (this might take some time)
 Done. Updating the local package-set file..
 ```
 
+#### Caching the Package Set
+
+It is important to have the hashes set in your `packages.dhall`, like this:
+
+```haskell
+...
+
+let mkPackage =
+ https://raw.githubusercontent.com/spacchetti/spacchetti/0.12.2-20190210/src/mkPackage.dhall sha256:0b197efa1d397ace6eb46b243ff2d73a3da5638d8d0ac8473e8e4a8fc528cf57
+
+let upstream =
+ https://raw.githubusercontent.com/spacchetti/spacchetti/0.12.2-20190210/src/packages.dhall sha256:1bee3f7608ca0f87a88b4b8807cb6722ab9ce3386b68325fbfa71d7211c1cf51
+
+...
+```
+
+The reason why it's so important is that (apart from [the safety guarantees][dhall-hash-safety])
+when your imports are protected by a hash they will be cached, considerably speeding up all
+the config-related operations.
+
+You can freeze the imports in your package set by running:
+
+```bash
+$ spago freeze
+```
+
 ### Building, bundling and testing a project
 
 We can build the project and its dependencies by running:
@@ -554,3 +581,4 @@ We have two commands for it:
 [todomvc]: https://github.com/f-f/purescript-react-basic-todomvc
 [purec]: https://github.com/pure-c/purec
 [purerl]: https://github.com/purerl/purescript
+[dhall-hash-safety]: https://github.com/dhall-lang/dhall-lang/wiki/Safety-guarantees#code-injection

app/Main.hs

@@ -57,6 +57,9 @@ data Command
  -- | Upgrade the package-set to the latest release
  | SpacchettiUpgrade
 
+ -- | Freeze the package-set so it will be cached
+ | Freeze
+
  -- | ### Commands for working with Psc-Package
  --
  -- Do the boilerplate of the local project setup to override and add arbitrary packages
@@ -96,6 +99,7 @@ parser
  T.<|> bundle
  T.<|> makeModule
  T.<|> spacchettiUpgrade
+ T.<|> freeze
  T.<|> pscPackageLocalSetup
  T.<|> pscPackageInsDhall
  T.<|> pscPackageClean
@@ -176,6 +180,10 @@ parser
  = T.subcommand "spacchetti-upgrade" "Upgrade the upstream in packages.dhall to the latest Spacchetti release"
  $ pure SpacchettiUpgrade
 
+ freeze
+ = T.subcommand "freeze" "Add hashes to the package-set, so it will be cached"
+ $ pure Freeze
+
  version
  = T.subcommand "version" "Show spago version"
  $ pure Version
@@ -201,6 +209,7 @@ main = do
  Verify limitJobs package -> Spago.Packages.verify limitJobs (Just package)
  VerifySet limitJobs -> Spago.Packages.verify limitJobs Nothing
  SpacchettiUpgrade -> Spago.Packages.upgradeSpacchetti
+ Freeze -> Spago.Packages.freeze
  Build limitJobs paths pursArgs -> Spago.Build.build limitJobs paths pursArgs
  Test modName limitJobs paths pursArgs -> Spago.Build.test modName limitJobs paths pursArgs
  Repl paths pursArgs -> Spago.Build.repl paths pursArgs

app/Spago/Messages.hs

@@ -83,6 +83,12 @@ upgradingPackageSet newTag = makeMessage
  , "Fetching the new one and generating hashes.. (this might take some time)"
  ]
 
+freezePackageSet :: Text
+freezePackageSet = makeMessage
+ [ "Generating hashes for the package-set so it will be cached."
+ , "This might take some time..."
+ ]
+
 packageSetVersionWarning :: Text
 packageSetVersionWarning = makeMessage
  [ "WARNING: the package-set version you're on doesn't check if the version of the"

app/Spago/PackageSet.hs

@@ -2,6 +2,7 @@ module Spago.PackageSet
  ( upgradeSpacchetti
  , checkPursIsUpToDate
  , makePackageSetFile
+ , freeze
  , path
  , pathText
  , PackageSet
@@ -93,6 +94,13 @@ makePackageSetFile force = do
  Dhall.Format.format Dhall.Pretty.Unicode (Just $ Text.unpack pathText)
 
 
+-- | Freeze the package-set imports so they can be cached
+freeze :: IO ()
+freeze = do
+ echo Messages.freezePackageSet
+ Dhall.Freeze.freeze (Just $ Text.unpack pathText) False defaultStandardVersion
+
+
 data RawPackageSet = RawPackageSet
  { mkPackage :: Dhall.Import
  , upstream :: Dhall.Import

app/Spago/Packages.hs

@@ -7,6 +7,7 @@ module Spago.Packages
  , getGlobs
  , getProjectDeps
  , PackageSet.upgradeSpacchetti
+ , PackageSet.freeze
  , PackageSet.PackageName(..)
  , PackagesFilter(..)
  ) where