UpdateController/update_psa

#!/bin/bash
# set -x

source ./log_helpers
source ./git_helpers

# source ./update_helpers.sh
# source ./opkg_helpers.sh
source ./update_psa_helpers

source ./read_config

###############################################################################
# update_psa
# 
# Implementing the UpdateController (see below). UpdateController is waiting
# for an external trigger by the DeviceController (DC). The trigger is sent via
# an UNIX-pipe (=fifo). When DC triggers UpdateController, it has to check if
# an update is possible, i.e. is has to lock the PSA for the update procedure.
# UpdateController will send back the update-result to DeviceController
# which unlocks the PSA to return to nomal operation.
#
# If UpdateController has been triggered, it checks out a predefined git-
# repository. As a sanity check it makes sure that there are some changes in 
# the repository. In case there are no changes, it issues an error message
# to DC and returns to its wait-state.
#
# Otherwise it checks if the changed files are correct (using md5) and if
# the new files are valid for the PSA. If there is some problem, it issues an
# error message to DC, reverts the git-repository to its previous state and
# returns to its wait-state.
#
# Otherwise it makes a backup of the current state of the PSA, and if there
# are opkg-packages to install it runs a dry installation process using opkg.
# In case of error, it issues an error message to DC, deletes the backup,
# reverts # the git-repository to its previous state and returns to its
# wait-state.
#
# Otherwise, it copies all new files to their target locations and in case
# of opkg-packages, it installs the packages.
#
# In case of error it restores the previous state using the backup and 
# reinstalls the previous opkg-package(s). It issues an error message to
# DC and returns to its wait-state.
#
# Otherwise the update went well, and it does some cleanup, sends a success
# message to DC and returns to its wait-state. 
#                                                                           
###############################################################################
#                                                                             
#                            UPDATE PROCEDURE
#                                                                           
###############################################################################
update() {
    local try_update_count=0
    local func="${FUNCNAME[0]}"

    # read config parameters
    # read_config
                
    log_debug "$func:${LINENO}: fetch/merge updates..."
   
    # Fetch new updates (using git)
    while :
    do
        local repository_is_already_up_to_date=""
        if ! fetch_customer_updates repository_is_already_up_to_date; then
            if [ "$repository_is_already_up_to_date" = "yes" ]; then
                log_error "$func:${LINENO}: $customer_id is up-to-date"\
                    "-> no files to update -> no psa update"
                exit 1
            fi
            try_updates_count=$((try_updates_count+1))
            if [[ "$try_updates_count" -eq 5 ]]; then
                log_error "$func:${LINENO}: fetch/merging failed" ; exit 1
            fi
            sleep 60s
        else
            # Fetched updates successfully 
            try_updates_count=0
            break
        fi
    done

    # Backup before any updates in case some previous test was wrong
    if ! backup_previous_version; then
        log_error "$func:${LINENO}: backup failed"
        revert_customer_repository ; exit 1
    fi

    files=$(changed_file_names)
    if ! check_md5_for_changed_customer_files $files ; then
        log_error "$func:${LINENO}: new customer files wrong"
        revert_customer_repository ; exit 1
    fi
   
    if grep -qE ".*opkg_commands.*?" <<< $files; then
        # read opkg_cmds: each line respresents an opkg-command
        readarray opkg_commands < <(cat $opkg_cmds_file)
        for opkg_command in "${opkg_commands[@]}"; do
            if grep -qE "^\s*[#]+.*?$" <<< $opkg_command; then
                continue    # found comment line
            fi
           
            # FIXME: sollte nicht gebraucht werden 
            opkg_command=${opkg_command//[$'\r\n\t']/ }
            local package=$(printf '%s' "$opkg_command" | awk '{ print $NF }')

            local opkg_output=()
            if ! exec_opkg_info "$package" opkg_output; then
                log_error "$func:${LINENO}: opkg --noaction $opkg_command failed"
                revert_customer_repository ; exit 1
            fi

            if ! check_md5_for_opkg_packages opkg_output; then
                log_error "$func:${LINENO}: wrong md5sum for some opkg packages"
                revert_customer_repository ; exit 1
            fi
            
            # perform a dry-run and check if everything might work as expected. 

            # Actually execute the opkg command
            if ! exec_opkg $opkg_command; then
                log_error "$func:${LINENO}: exec_opkg $opkg_command failed"
                fallback_to_previous_version
                revert_customer_repository ; exit 1
            fi
        done
    else
        log_info "$func:${LINENO}: no opkg commnds to execute"
    fi
    
    # Cleanup.
    if ! cleanup_previous_version; then
        log_error "$func:${LINENO}: cleanup_previous_version failed"
    fi
            
    log_info "$func:${LINENO}: success"
    exit 0
}

###############################################################################

if [ $# -ne 1 ] ; then
    echo "Usage: $0 filename"  
    exit 1 
else
    if [ -z $IFS ]; then
        IFS=$'\n'
    fi

    if read_config "$1" ; then
        # set -x
        if clone_customer_repository $repository_path ; then 
            update 
        fi
    fi
fi