mirror of
https://github.com/tailscale/tailscale.git
synced 2024-11-26 11:35:35 +00:00
c9a4dbe383
Previously, the build ended up embedding an empty string, which made the shell wrapper rebuild gocross on every invocation. This is still reasonably fast, but fixing the bypass shaves 80% off gocross's overhead when no rebuild is needed. Signed-off-by: David Anderson <danderson@tailscale.com>
103 lines
3.6 KiB
Bash
Executable File
103 lines
3.6 KiB
Bash
Executable File
#!/usr/bin/env sh
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# Copyright (c) Tailscale Inc & AUTHORS
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# SPDX-License-Identifier: BSD-3-Clause
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#
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# gocross-wrapper.sh is a wrapper that can be aliased to 'go', which
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# transparently builds gocross using a "bootstrap" Go toolchain, and
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# then invokes gocross.
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set -eu
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if [ "${CI:-}" = "true" ]; then
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set -x
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fi
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# Locate a bootstrap toolchain and (re)build gocross if necessary. We run all of
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# this in a subshell because posix shell semantics make it very easy to
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# accidentally mutate the input environment that will get passed to gocross at
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# the bottom of this script.
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(
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repo_root="$(dirname $0)/../.."
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# Figuring out if gocross needs a rebuild, as well as the rebuild itself, need
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# to happen with CWD inside this repo. Since we're in a subshell entirely
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# dedicated to wrangling gocross and toolchains, cd over now before doing
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# anything further so that the rest of this logic works the same if gocross is
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# being invoked from somewhere else.
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cd "$repo_root"
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toolchain="$HOME/.cache/tailscale-go"
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if [ -d "$toolchain" ]; then
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# A toolchain exists, but is it recent enough to compile gocross? If not,
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# wipe it out so that the next if block fetches a usable one.
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want_go_minor=$(egrep '^go ' "$repo_root/go.mod" | cut -f2 -d'.')
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have_go_minor=$(cut -f2 -d'.' <$toolchain/VERSION)
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if [ -z "$have_go_minor" -o "$have_go_minor" -lt "$want_go_minor" ]; then
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rm -rf "$toolchain" "$toolchain.extracted"
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fi
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fi
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if [ ! -d "$toolchain" ]; then
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mkdir -p "$HOME/.cache"
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# We need any Go toolchain to build gocross, but the toolchain also has to
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# be reasonably recent because we upgrade eagerly and gocross might not
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# build with Go N-1. So, if we have no cached tailscale toolchain at all,
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# fetch the initial one in shell. Once gocross is built, it'll manage
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# updates.
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read -r REV <$repo_root/go.toolchain.rev
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case "$REV" in
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/*)
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toolchain="$REV"
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;;
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*)
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# This works for linux and darwin, which is sufficient
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# (we do not build tailscale-go for other targets).
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HOST_OS=$(uname -s | tr A-Z a-z)
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HOST_ARCH="$(uname -m)"
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if [ "$HOST_ARCH" = "aarch64" ]; then
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# Go uses the name "arm64".
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HOST_ARCH="arm64"
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elif [ "$HOST_ARCH" = "x86_64" ]; then
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# Go uses the name "amd64".
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HOST_ARCH="amd64"
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fi
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rm -rf "$toolchain" "$toolchain.extracted"
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curl -f -L -o "$toolchain.tar.gz" "https://github.com/tailscale/go/releases/download/build-${REV}/${HOST_OS}-${HOST_ARCH}.tar.gz"
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mkdir -p "$toolchain"
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(cd "$toolchain" && tar --strip-components=1 -xf "$toolchain.tar.gz")
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echo "$REV" >"$toolchain.extracted"
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rm -f "$toolchain.tar.gz"
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;;
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esac
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fi
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# Binaries run with `gocross run` can reinvoke gocross, resulting in a
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# potentially fancy build that invokes external linkers, might be
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# cross-building for other targets, and so forth. In one hilarious
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# case, cmd/cloner invokes go with GO111MODULE=off at some stage.
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#
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# Anyway, build gocross in a stripped down universe.
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gocross_path="$repo_root/gocross"
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gocross_ok=0
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wantver="$(git rev-parse HEAD)"
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if [ -x "$gocross_path" ]; then
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gotver="$($gocross_path gocross-version 2>/dev/null || echo '')"
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if [ "$gotver" = "$wantver" ]; then
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gocross_ok=1
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fi
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fi
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if [ "$gocross_ok" = "0" ]; then
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unset GOOS
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unset GOARCH
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unset GO111MODULE
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unset GOROOT
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export CGO_ENABLED=0
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"$toolchain/bin/go" build -o "$gocross_path" -ldflags "-X tailscale.com/version.gitCommitStamp=$wantver" tailscale.com/tool/gocross
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fi
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) # End of the subshell execution.
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exec "$(dirname $0)/../../gocross" "$@"
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