Migrate crates.io-index sync script to docker (#80)

* crates-io-index: add

* crates-io-index: use is_empty func

* crates-io-index: add user.name and user.email

* crates-io-index: fix typo

* crates-io-index: fix typo

* crates-io-index: add missing env names in comments

README.md

@@ -14,6 +14,7 @@
     - [aptsync](#aptsync)
     - [apt-sync](#apt-sync)
     - [archvsync](#archvsync)
+    - [crates-io-index](#crates-io-index)
     - [debian-cd](#debian-cd)
     - [docker-ce](#docker-ce)
     - [fedora](#fedora)
@@ -130,6 +131,20 @@ A.K.A. [ftpsync](https://anonscm.debian.org/cgit/mirror/archvsync.git/)
 | ------------- | ---------------------------------------------- |
 | `IGNORE_LOCK` | Purge lockfiles at first. Defaults to `false`. |
 
+### crates-io-index
+
+[![crates-io-index](https://img.shields.io/docker/image-size/ustcmirror/crates-io-index/latest)](https://hub.docker.com/r/ustcmirror/crates-io-index "crates-io-index")
+[![crates-io-index](https://img.shields.io/docker/pulls/ustcmirror/crates-io-index)](https://hub.docker.com/r/ustcmirror/crates-io-index "crates-io-index")
+
+A dedicated script to sync <https://github.com/rust-lang/crates.io-index>.
+
+| Parameter        | Description                                                                                                |
+| ---------------- | ---------------------------------------------------------------------------------------------------------- |
+| `CRATES_PROXY`   | The URL that crates will be redirected to. Defaults to `https://crates-io.proxy.ustclug.org/api/v1/crates` |
+| `CRATES_GITMSG`  | The commit message of `config.json`. Defaults to `Redirect to USTC Mirrors`                                |
+| `CRATES_GITMAIL` | `user.email` when committing `config.json`. Defaults to `lug AT ustc.edu.cn`                               |
+| `CRATES_GITNAME` | `user.name` when committing `config.json`. Defaults to `mirror`                                            |
+
 ### debian-cd
 
 [![debian-cd](https://img.shields.io/docker/image-size/ustcmirror/debian-cd/latest)](https://hub.docker.com/r/ustcmirror/debian-cd "debian-cd")

crates-io-index/Dockerfile

@@ -0,0 +1,4 @@
+FROM ustcmirror/base:alpine
+LABEL maintainer "Keyu Tao <taoky AT lug.ustc.edu.cn>"
+RUN apk add --no-cache git
+ADD sync.sh /

crates-io-index/sync.sh

@@ -0,0 +1,56 @@
+#!/bin/bash
+
+# Migrated to yuki (docker) by @taoky
+# Created by @ksqsf
+# Based on the original version written by @knight42
+
+# ENVS:
+# CRATES_PROXY=
+# CRATES_GITMSG=
+# CRATES_GITMAIL=
+# CRATES_GITNAME=
+
+is_empty() {
+    [[ -z $(ls -A "$1" 2>/dev/null) ]]
+}
+
+set -e
+[[ -n $DEBUG ]] && set -x
+
+CRATES_PROXY="${CRATES_PROXY:-https://crates-io.proxy.ustclug.org/api/v1/crates}"
+CRATES_GITMSG="${CRATES_GITMSG:-Redirect to USTC Mirrors}"
+CRATES_GITMAIL="${CRATES_GITMAIL:-lug AT ustc.edu.cn}"
+CRATES_GITNAME="${CRATES_GITNAME:-mirror}"
+
+ensure_redirect() {
+    pushd "$TO"
+    if grep -F -q "$CRATES_PROXY" 'config.json'; then
+        return
+    else
+        cat <<EOF > 'config.json'
+{
+    "dl": "$CRATES_PROXY",
+    "api": "https://crates.io/"
+}
+EOF
+        git add config.json
+        git -c user.name="$CRATES_GITNAME" -c user.email="$CRATES_GITMAIL" commit -qm "$CRATES_GITMSG"
+    fi
+    popd
+}
+
+# crates.io-index has a custom ensure_redirect logic
+# so now we don't use gitsync here.
+
+if ! is_empty "$TO"; then
+    cd "$TO"
+    git fetch origin
+    git reset --hard origin/master
+    ensure_redirect
+    git repack -adb
+    git gc --auto
+    git update-server-info
+else
+    git clone 'https://github.com/rust-lang/crates.io-index.git' "$TO"
+    ensure_redirect
+fi