1 files changed, 152 insertions, 0 deletions
diff --git a/third_party/bazel/rules_haskell/haskell/gen_ghc_bindist.py b/third_party/bazel/rules_haskell/haskell/gen_ghc_bindist.py
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+++ b/third_party/bazel/rules_haskell/haskell/gen_ghc_bindist.py
@@ -0,0 +1,152 @@
+#!/usr/bin/env python
+
+# This is a happy-path tool to download the bindist
+# download paths and hashes, for maintainers.
+# It uses the hashes provided by download.haskell.org.
+
+from __future__ import print_function
+
+import pprint
+import sys
+import urllib2
+
+# All GHC versions we generate.
+# `version` is the version number
+# `distribution_version` is a corrected name
+# (sometimes bindists have errors and are updated by new bindists)
+# `ignore_prefixes` is the prefix of files to ignore
+# `ignore_suffixes` is the suffix of files to ignore
+VERSIONS = [
+    { "version": "8.6.5" },
+    { "version": "8.6.4" },
+    { "version": "8.6.3" },
+    { "version": "8.6.2" },
+    { "version": "8.4.4" },
+    { "version": "8.4.3" },
+    { "version": "8.4.2" },
+    { "version": "8.4.1" },
+    { "version": "8.2.2" },
+    { "version": "8.0.2",
+      "ignore_suffixes": [".patch"] },
+    { "version": "7.10.3",
+      "distribution_version": "7.10.3b",
+      "ignore_prefixes": ["ghc-7.10.3-", "ghc-7.10.3a-"],
+      "ignore_suffixes": [".bz2", ".patch" ] }
+]
+
+# All architectures we generate.
+# bazel: bazel name
+# upstream: download.haskell.org name
+ARCHES = [
+    { "bazel": "linux_amd64",
+      "upstream": "x86_64-deb8-linux", },
+    { "bazel": "darwin_amd64",
+      "upstream": "x86_64-apple-darwin" },
+    { "bazel": "windows_amd64",
+      "upstream": "x86_64-unknown-mingw32" },
+]
+
+
+# An url to a bindist tarball.
+def link_for_tarball(arch, version):
+    return "https://downloads.haskell.org/~ghc/{ver}/ghc-{ver}-{arch}.tar.xz".format(
+        ver = version,
+        arch = arch,
+    )
+
+# An url to a version's tarball hashsum file.
+# The files contain the hashsums for all arches.
+def link_for_sha256_file(version):
+    return "https://downloads.haskell.org/~ghc/{ver}/SHA256SUMS".format(
+        ver = version
+    )
+
+# Parses the tarball hashsum file for a distribution version.
+def parse_sha256_file(content, version, url):
+    res = {}
+    errs = []
+    for line in content:
+        # f5763983a26dedd88b65a0b17267359a3981b83a642569b26334423f684f8b8c  ./ghc-8.4.3-i386-deb8-linux.tar.xz
+        (hash, file_) = line.strip().split("  ./")
+        prefix = "ghc-{ver}-".format(ver = version.get("distribution_version", version['version']))
+        suffix = ".tar.xz"
+
+        # filter ignored files
+        if   any([file_.startswith(p) for p in version.get("ignore_prefixes", [])]) \
+          or any([file_.endswith(s)   for s in version.get("ignore_suffixes", [])]):
+            continue
+
+        if file_.startswith(prefix) and file_.endswith(suffix):
+            # i386-deb8-linux
+            name = file_[len(prefix):-len(suffix)]
+            res[name] = hash
+        else:
+            errs.append("Can't parse the sha256 field for {ver}: {entry}".format(
+                ver = version['version'], entry = line.strip()))
+
+    if errs:
+        eprint("Errors parsing file at " + url + ". Either fix or ignore the lines (ignore_suffixes/ignore_prefixes).")
+        for e in errs:
+            eprint(e)
+        exit(1)
+
+    return res
+
+# Print to stderr.
+def eprint(mes):
+    print(mes, file = sys.stderr)
+
+# Main.
+if __name__ == "__main__":
+
+    # Fetch all hashsum files
+    # grab : { version: { arch: sha256 } }
+    grab = {}
+    for ver in VERSIONS:
+        eprint("fetching " + ver['version'])
+        url = link_for_sha256_file(ver['version'])
+        res = urllib2.urlopen(url)
+        if res.getcode() != 200:
+            eprint("download of {} failed with status {}".format(url, res.getcode()))
+            sys.exit(1)
+        else:
+            grab[ver['version']] = parse_sha256_file(res, ver, url)
+
+    # check whether any version is missing arches we need
+    # errs : { version: set(missing_arches) }
+    errs = {}
+    for ver, hashes in grab.items():
+      real_arches = frozenset(hashes.keys())
+      needed_arches = frozenset([a['upstream'] for a in ARCHES])
+      missing_arches = needed_arches.difference(real_arches)
+      if missing_arches:
+          errs[ver] = missing_arches
+    if errs:
+        for ver, missing in errs.items():
+            eprint("version {ver} is missing hashes for required architectures {arches}".format(
+                ver = ver,
+                arches = missing))
+
+    # fetch the arches we need and create the GHC_BINDISTS dict
+    # ghc_bindists : { version: { bazel_arch: (tarball_url, sha256_hash) } }
+    ghc_bindists = {}
+    for ver, hashes in grab.items():
+        # { bazel_arch: (tarball_url, sha256_hash) }
+        arch_dists = {}
+        for arch in ARCHES:
+            hashes[arch['upstream']]
+            arch_dists[arch['bazel']] = (
+                link_for_tarball(arch['upstream'], ver),
+                hashes[arch['upstream']]
+            )
+        ghc_bindists[ver] = arch_dists
+
+    # Print to stdout. Be aware that you can't `> foo.bzl`,
+    # because that truncates the source file which is needed
+    # for bazel to run in the first place.
+    print(""" \
+# Generated with `bazel run @io_tweag_rules_haskell//haskell:gen-ghc-bindist | sponge haskell/private/ghc_bindist_generated.bzl`
+# To add a version or architecture, edit the constants in haskell/gen_ghc_bindist.py
+GHC_BINDIST = \\""")
+    pprint.pprint(ghc_bindists)
+