install_cni_chaining

#!/usr/bin/env bash

# Copyright 2022 Antrea Authors
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

source logging
source module_utils

HOST_CNI_NET_DIR="/host/etc/cni/net.d"

run_monitor="false"

function usage {
    echo "install_cni_chaining"
    echo -e "  -h|--help           Print help message"
    echo -e "  --monitor           Monitor the CNI conf file and re-apply changes every time it is overwritten"
}

while (( "$#" )); do
  case "$1" in
    -h|--help)
      usage
      exit 0
      ;;
    --monitor)
      run_monitor="true"
      ;;
    -*|--*) # unsupported flags
      echo "Error: unsupported flag $1" >&2
      exit 1
      ;;
    *) # standalone arguments are not supported
      echo "Error: unsupported argument $1" >&2
      exit 1
      ;;
  esac
  shift
done

# Find the cni conf file with lowest name, which is not installed by us
while true; do
  cni_conf_name=$(ls "$HOST_CNI_NET_DIR" | grep -v antrea | head -n1)
  if [[ ! -z $cni_conf_name ]]; then
    break
  fi
  log_info "install_cni_chaining" "CNI conf file not found. Retrying after 2 secs"
  sleep 2s
done
cni_conf_path="$HOST_CNI_NET_DIR/$cni_conf_name"

# EKS uses 10-aws.conflist
# AKS uses 10-azure.conflist
cni_conf_name_antrea="05-antrea.conflist"
cni_conf_path_antrea="$HOST_CNI_NET_DIR/$cni_conf_name_antrea"

cni_conf_sha=""

function update_cni_conf {
    log_info "install_cni_chaining" "updating CNI conf file $cni_conf_name -> $cni_conf_name_antrea"

    # We use the following steps:
    # 1. read the input file once and store its contents in a variable
    # 2. perform the necessary changes on the variable contents
    # 3. write the variable contents to the output file if necessary
    content=$(cat $cni_conf_path)
    cni_conf_sha="$(echo -n "$content" | sha256sum | while read -r s _; do echo "$s"; done)"

    echo "$content" | grep -sq "azure"
    if [[ $? == 0 ]]; then
        # Note that in more recent AKS versions, transparent is the default:
        # https://github.com/Azure/azure-container-networking/pull/709
        content="$(echo "$content" | sed 's/"mode":"bridge",/"mode":"transparent",/g')"
    fi

    echo "$content" | jq '.plugins[] | .type' | grep -sq antrea
    if [[ $? != 0 ]]; then
        content="$(echo "$content" | jq '.plugins += [{"type": "antrea"}]')"
    fi

    # we only write to the file if an update is necessary
    cmp -s <(echo "$content") $cni_conf_path_antrea
    if [[ $? != 0 ]]; then
        echo "$content" > $cni_conf_path_antrea
    else
        log_info "install_cni_chaining" "CNI conf file is already up-to-date"
    fi
}

# monitor will start a watch on host's CNI config directory.
# when we detect a change to the CNI conf file, we call update_cni_conf.
function monitor {
    inotifywait -m "$HOST_CNI_NET_DIR" -e create,close_write |
        while read -r directory action filename; do
            if [[ "$filename" == "$cni_conf_name" ]]; then
                log_info "install_cni_chaining" "inotify event in $directory: $action $filename"
                sha="$(sha256sum "$directory/$filename" | while read -r s _; do echo "$s"; done)"
                if [[ "$sha" == "" ]]; then
                    log_warning "install_cni_chaining" "unable to compute sha, file may have been deleted"
                    continue
                fi
                if [[ "$sha" == "$cni_conf_sha" ]]; then
                    log_info "install_cni_chaining" "sha matches existing one, ignoring event"
                    continue
                fi
                update_cni_conf
            fi
        done
}

# Update conf file the first time
update_cni_conf

# Install Antrea binary file
install -m 755 /usr/local/bin/antrea-cni /host/opt/cni/bin/antrea

id

if [[ -z "${SKIP_LOADING_KERNEL_MODULES:-}" ]]; then
    # Load the OVS kernel module if not built-in
    if ! is_module_builtin "openvswitch"; then
        modprobe openvswitch || { echo "Failed to load the OVS kernel module from the container, try running 'modprobe openvswitch' on your Nodes"; exit 1;}
    else
        log_info "install_cni_chaining" "Module openvswitch is built-in"
    fi
fi

if [[ "$run_monitor" == "false" ]]; then
    exit 0
fi

SLEEP_PID=
MONITOR_PID=
function quit {
    log_info "install_cni_chaining" "Exiting"
    # terminate background monitor process
    if [ "$MONITOR_PID" != "" ]; then kill $MONITOR_PID > /dev/null 2>&1 || true; fi
    # terminate background sleep process
    if [ "$SLEEP_PID" != "" ]; then kill $SLEEP_PID > /dev/null 2>&1 || true; fi
    exit 0
}

# Do not trap EXIT as it would then ignore the "exit 0" statement in quit and
# exit with code 128 + SIGNAL
trap "quit" INT TERM HUP

log_info "install_cni_chaining" "Starting inotify monitor for $cni_conf_name"

monitor &
MONITOR_PID=$!
while true; do
  # sleep so script never finishes
  # we start sleep in bg so we can trap signals
  sleep 3600 &
  SLEEP_PID=$!
  wait $SLEEP_PID
done