From 73d6c9d469d1429999ea2e980b3ac4c63a3e0dd4 Mon Sep 17 00:00:00 2001
From: Darko Poljak <foss@ungleich.ch>
Date: Sun, 27 Sep 2020 10:17:35 +0200
Subject: [PATCH] Add custom remote copy/exec examples

---
 docs/src/cdist-remote-exec-copy.rst | 389 +++++++++++++++++++++++++++-
 1 file changed, 388 insertions(+), 1 deletion(-)

diff --git a/docs/src/cdist-remote-exec-copy.rst b/docs/src/cdist-remote-exec-copy.rst
index bb818310..e7b7b226 100644
--- a/docs/src/cdist-remote-exec-copy.rst
+++ b/docs/src/cdist-remote-exec-copy.rst
@@ -10,7 +10,7 @@ By default this is accomplished with ssh and scp respectively.
 The default implementations used by cdist are::
 
     __remote_exec: ssh -o User=root
-    __remote_copy: scp -o User=root
+    __remote_copy: scp -o User=root -q
 
 The user can override these defaults by providing custom implementations and
 passing them to cdist with the --remote-exec and/or --remote-copy arguments.
@@ -26,3 +26,390 @@ specified by enclosed in square brackets (see :strong:`ssh`\ (1) and
 With this simple interface the user can take total control of how cdist
 interacts with the target when required, while the default implementation 
 remains as simple as possible.
+
+
+Examples
+--------
+
+Here are examples of using alternative __remote_copy and __remote_exec scripts.
+
+All scripts from below are present in cdist sources in `other/examples/remote`
+directory.
+
+ssh
+~~~
+
+Same as cdist default.
+
+**copy**
+
+Usage: cdist config --remote-copy "/path/to/this/script" target_host
+
+.. code-block:: sh
+
+    #echo "$@" | logger -t "cdist-ssh-copy"
+    scp -o User=root -q $@
+
+**exec**
+
+Usage: cdist config --remote-exec "/path/to/this/script" target_host
+
+.. code-block:: sh
+
+    #echo "$@" | logger -t "cdist-ssh-exec"
+    ssh -o User=root $@
+
+local
+~~~~~
+
+This effectively turns remote calling into local calling. Probably most useful
+for the unit testing.
+
+**copy**
+
+.. code-block:: sh
+
+    code="$(echo "$@" | sed "s|\([[:space:]]\)$__target_host:|\1|g")"
+    cp -L $code
+
+**exec**
+
+.. code-block:: sh
+
+    target_host=$1; shift
+    echo "$@" | /bin/sh 
+
+chroot
+~~~~~~
+
+**copy**
+
+Usage: cdist config --remote-copy "/path/to/this/script /path/to/your/chroot" target-id
+
+.. code-block:: sh
+
+    log() {
+       #echo "$@" | logger -t "cdist-chroot-copy"
+       :
+    }
+
+    chroot="$1"; shift
+    target_host="$__target_host"
+
+    # replace target_host with chroot location
+    code="$(echo "$@" | sed "s|$target_host:|$chroot|g")"
+
+    log "target_host: $target_host"
+    log "chroot: $chroot"
+    log "$@"
+    log "$code"
+
+    # copy files into chroot
+    cp $code
+
+    log "-----"
+
+**exec**
+
+Usage: cdist config --remote-exec "/path/to/this/script /path/to/your/chroot" target-id
+
+.. code-block:: sh
+
+    log() {
+       #echo "$@" | logger -t "cdist-chroot-exec"
+       :
+    }
+
+    chroot="$1"; shift
+    target_host="$1"; shift
+
+    script=$(mktemp "${chroot}/tmp/chroot-${0##*/}.XXXXXXXXXX")
+    trap cleanup INT TERM EXIT
+    cleanup() {
+       [ $__cdist_debug ] || rm "$script"
+    }
+
+    log "target_host: $target_host"
+    log "script: $script"
+    log "@: $@"
+    echo "#!/bin/sh -l" > "$script"
+    echo "$@" >> "$script"
+    chmod +x "$script"
+
+    relative_script="${script#$chroot}"
+    log "relative_script: $relative_script"
+
+    # run in chroot
+    chroot "$chroot" "$relative_script"
+
+    log "-----"
+
+rsync
+~~~~~
+
+**copy**
+
+Usage: cdist config --remote-copy /path/to/this/script target_host
+
+.. code-block:: sh
+
+    # For rsync to do the right thing, the source has to end with "/" if it is
+    # a directory. The below preprocessor loop takes care of that.
+
+    # second last argument is the source
+    source_index=$(($#-1))
+    index=0
+    for arg in $@; do
+       if [ $index -eq 0 ]; then
+          # reset $@
+          set --
+       fi
+       index=$((index+=1))
+       if [ $index -eq $source_index -a -d "$arg" ]; then
+          arg="${arg%/}/"
+       fi
+       set -- "$@" "$arg"
+    done
+
+    rsync --backup --suffix=~cdist -e 'ssh -o User=root' $@
+
+schroot
+~~~~~~~
+
+__remote_copy and __remote_exec scripts to run cdist against a chroot on the
+target host over ssh.
+
+**copy**
+
+Usage: cdist config --remote-copy "/path/to/this/script schroot-chroot-name" target_host
+
+
+.. code-block:: sh
+
+    log() {
+       #echo "$@" | logger -t "cdist-schroot-copy"
+       :
+    }
+
+    chroot_name="$1"; shift
+    target_host="$__target_host"
+
+    # get directory for given chroot_name
+    chroot="$(ssh -o User=root -q $target_host schroot -c $chroot_name --config | awk -F = '/directory=/ {print $2}')"
+
+    # prefix destination with chroot
+    code="$(echo "$@" | sed "s|$target_host:|$target_host:$chroot|g")"
+
+    log "target_host: $target_host"
+    log "chroot_name: $chroot_name"
+    log "chroot: $chroot"
+    log "@: $@"
+    log "code: $code"
+
+    # copy files into remote chroot
+    scp -o User=root -q $code
+
+    log "-----"
+
+**exec**
+
+Usage: cdist config --remote-exec "/path/to/this/script schroot-chroot-name" target_host
+
+.. code-block:: sh
+
+    log() {
+       #echo "$@" | logger -t "cdist-schroot-exec"
+       :
+    }
+
+    chroot_name="$1"; shift
+    target_host="$1"; shift
+
+    code="ssh -o User=root -q $target_host schroot -c $chroot_name -- $@"
+
+    log "target_host: $target_host"
+    log "chroot_name: $chroot_name"
+    log "@: $@"
+    log "code: $code"
+
+    # run in remote chroot
+    $code
+
+    log "-----"
+
+schroot-uri
+~~~~~~~~~~~
+
+__remote_exec/__remote_copy script to run cdist against a schroot target URI.
+
+Usage::
+
+    cdist config \
+        --remote-exec "/path/to/this/script exec" \
+        --remote-copy "/path/to/this/script copy" \
+        target_uri
+
+    # target_uri examples:
+    schroot:///chroot-name
+    schroot://foo.ethz.ch/chroot-name
+    schroot://user-name@foo.ethz.ch/chroot-name
+
+    # and how to match them in .../manifest/init
+    case "$target_host" in
+    schroot://*)
+        # any schroot
+    ;;
+    schroot://foo.ethz.ch/*)
+        # any schroot on specific host
+    ;;
+    schroot://foo.ethz.ch/chroot-name)
+        # specific schroot on specific host
+    ;;
+    schroot:///chroot-name)
+        # specific schroot on localhost
+    ;;
+    esac
+
+**copy/exec**
+
+.. code-block:: sh
+
+    my_name="${0##*/}"
+    mode="$1"; shift
+
+    log() {
+       # uncomment me for debugging
+       #echo "$@" | logger -t "cdist-$my_name-$mode"
+       :
+    }
+
+    die() {
+       echo "$@" >&2
+       exit 1
+    }
+
+
+    uri="$__target_host"
+
+    scheme="${uri%%:*}"; rest="${uri#$scheme:}"; rest="${rest#//}"
+    authority="${rest%%/*}"; rest="${rest#$authority}"
+    path="${rest%\?*}"; rest="${rest#$path}"
+    schroot_name="${path#/}"
+
+    [ "$scheme" = "schroot" ] || die "Failed to parse scheme from __target_host ($__target_host). Expected 'schroot', got '$scheme'"
+    [ -n "$schroot_name" ] || die "Failed to parse schroot name from __target_host: $__target_host"
+
+    case "$authority" in
+       '')
+          # authority is empty, neither user nor host given
+          user=""
+          host=""
+       ;; 
+       *@*)
+          # authority contains @, take user from authority
+          user="${authority%@*}"
+          host="${authority#*@}"
+       ;; 
+       *) 
+          # no user in authority, default to root
+          user="root"
+          host="$authority"
+       ;;
+    esac
+
+    log "mode: $mode"
+    log "@: $@"
+    log "uri: $uri"
+    log "scheme: $scheme"
+    log "authority: $authority"
+    log "user: $user"
+    log "host: $host"
+    log "path: $path"
+    log "schroot_name: $schroot_name"
+
+    exec_prefix=""
+    copy_prefix=""
+    if [ -n "$host" ]; then
+       # we are working on a remote host
+       exec_prefix="ssh -o User=$user -q $host"
+       copy_prefix="scp -o User=$user -q"
+       copy_destination_prefix="$host:"
+    else
+       # working on local machine
+       copy_prefix="cp"
+       copy_destination_prefix=""
+    fi
+    log "exec_prefix: $exec_prefix"
+    log "copy_prefix: $copy_prefix"
+    log "copy_destination_prefix: $copy_destination_prefix"
+
+    case "$mode" in
+       exec)
+          # In exec mode the first argument is the __target_host which we already got from env. Get rid of it.
+          shift
+          code="$exec_prefix schroot -c $schroot_name -- sh -c '$@'"
+       ;;
+       copy)
+          # get directory for given chroot_name
+          schroot_directory="$($exec_prefix schroot -c $schroot_name --config | awk -F = '/directory=/ {print $2}')"
+          [ -n "$schroot_directory" ] || die "Failed to retreive schroot directory for schroot: $schroot_name"
+          log "schroot_directory: $schroot_directory"
+          # prefix destination with chroot
+          code="$copy_prefix $(echo "$@" | sed "s|$uri:|${copy_destination_prefix}${schroot_directory}|g")"
+       ;;
+       *) die "Unknown mode: $mode";;
+    esac
+
+    log "code: $code"
+
+    # Run the code
+    $code
+
+    log "-----"
+
+sudo
+~~~~
+
+**copy**
+
+Use rsync over ssh to copy files. Uses the "--rsync-path" option
+to run the remote rsync instance with sudo.
+
+This command assumes your ssh configuration is already set up in ~/.ssh/config.
+
+Usage: cdist config --remote-copy /path/to/this/script target_host
+
+.. code-block:: sh
+
+    # For rsync to do the right thing, the source has to end with "/" if it is
+    # a directory. The below preprocessor loop takes care of that.
+
+    # second last argument is the source
+    source_index=$(($#-1))
+    index=0
+    for arg in $@; do
+       if [ $index -eq 0 ]; then
+          # reset $@
+          set --
+       fi
+       index=$((index+=1))
+       if [ $index -eq $source_index -a -d "$arg" ]; then
+          arg="${arg%/}/"
+       fi
+       set -- "$@" "$arg"
+    done
+
+    rsync --copy-links --rsync-path="sudo rsync" -e 'ssh' "$@"
+
+**exec**
+
+Prefixes all remote commands with sudo.
+
+This command assumes your ssh configuration is already set up in ~/.ssh/config.
+
+Usage: cdist config --remote-exec "/path/to/this/script" target_host
+
+.. code-block:: sh
+
+    host="$1"; shift
+    ssh -q "$host" sudo sh -c \""$@"\"