TT#24920 Introduce 'ngcpcfg patch --from-customtt' for initial import

The new function will simplify initial customtt->patchtt
migration for end users. Some code was merged to be generic.

Also more tests were add here.

Change-Id: I7719f45275018818b2db82f6deee5b7428670a29

docs/ngcpcfg.txt

@@ -397,10 +397,14 @@ Note: This feature is only available if the ngcp-ngcpcfg-carrier package is inst
 
 Prints the log of local changes. Expand all changes if '-p' option is specified.
 
-  **patch** [--help] [<patchtt file(s)>]::
+  **patch** [--help | --from-customtt [<cusomtt file(s)>] | <patchtt file(s)>]::
 
 Generate customtt files using default templates and patchtt files.
 Using patchtt files automates template updating and simplifies customtt management.
+You can perform initial migration from customtt to patchtt using option '--from-customtt',
+ngcpcfg will process all/requested customtt files and generate patchtt files as a
+difference between template and current customtt files. You should normally
+execute '--from-customtt' only once during migration on patchtt.
 
   **pull**::
 

scripts/build

@@ -36,7 +36,7 @@ else
   "${SCRIPTS}"/check --ignore-branch-check
 fi
 
-"${SCRIPTS}"/patch
+"${SCRIPTS}"/patch "$@"
 
 # Kill all previous started tt2-daemon Perl processes if they were not stopped properly
 killall tt2-daemon 2>/dev/null || true

scripts/patch

@@ -23,38 +23,43 @@ cd "${NGCPCTL_MAIN}"
 patch_help() {
   export TIME_FORMAT=''
   log_info "'ngcpcfg patch' walks through all templates searching for '*.patchtt.tt2' files"
-  log_info "and generates '*.customtt.tt2' files based on the original template"
+  log_info "and generates '*.customtt.tt2' files based on the original template."
+  log_info "The option '--from-customtt' simplifies migration from customtt to patchtt."
   log_info ""
   log_info "Sample:"
-  log_info "  ngcpcfg patch [--help] [<patchtt file(s)>]"
+  log_info "  ngcpcfg patch [--help | --from-customtt [<cusomtt file(s)>] | <patchtt file(s)>]"
   log_info ""
   log_info "Run 'man ngcpcfg' for more information."
 }
 
 patch_search() {
-  log_debug "Searching for patchtt files"
+  local name="$1"
+  shift # remove the first 'patchtt/customtt'
+  local files=("$@")
 
-  local patchlist
-  patchlist=$(mktemp)
+  log_debug "Searching for ${name} files (requested '${files[*]}')"
+
+  local fileslist
+  fileslist=$(mktemp)
 
   local a="\.sp[12]?"
   local b="\.(web|db|prx|lb|slb)[0-9]+[ab]?"
-  local awk_regexp=".*patchtt\.tt2(${a}|${b})?$"
+  local awk_regexp=".*${name}\.tt2(${a}|${b})?$"
 
   for dir in ${CONFIG_POOL} ; do
     [ -n "${dir}" ] || log_error "${dir} doesn't exist"
-    # iterate over all files
-    while read -r patch ; do
-      # *NO* arguments provided via cmdline
-      if [ -z "${1:-}" ] ; then
-        log_debug "Found patch '${patch}'"
-        echo "${patch}" >> "${patchlist}"
+    log_debug "Iterate over all files in ${TEMPLATE_POOL_BASE%/}/${dir#/}"
+    while read -r file ; do
+      if [ "${#files[@]}" = "0" ] ; then
+        log_debug "NO arguments provided via cmdline"
+        log_debug "Found ${name} '${file}'"
+        echo "${file}" >> "${fileslist}"
       else
         # arguments (file list/pattern) provided via cmdline
-        for arg in "$@"; do
-          if echo "${patch}" | grep -q -- "${arg}" ; then
-            log_debug "Processing patch '${patch}' as requested"
-            echo "${patch}" >> "${patchlist}"
+        for arg in "${files[@]}"; do
+          if echo "${file}" | grep -q -- "${arg}" ; then
+            log_debug "Processing ${name} '${file}' as requested"
+            echo "${file}" >> "${fileslist}"
           fi
         done
       fi
@@ -62,24 +67,24 @@ patch_search() {
   done
 
   # output patch list, make sure we provide the file names just once
-  sort -u "${patchlist}"
+  sort -u "${fileslist}"
 
   if [ -n "${DEBUG:-}" ] ; then
     # send to stderr since stdout is used from outside
-    log_debug "Not removing temporary patchlist files since we are in debug mode:" >&2
-    log_debug "  patchlist = ${patchlist}" >&2
+    log_debug "Not removing temporary fileslist files since we are in debug mode:" >&2
+    log_debug "  fileslist = ${fileslist}" >&2
   else
-    rm -f "${patchlist}"
+    rm -f "${fileslist}"
   fi
 }
 
-patch_validate() {
+patch_validate_patch() {
   local patch="$1"
   log_debug "Validating patch: '${patch}'"
 
   if [ ! -f "${patch}" ] ; then
     log_error "Missing patch file '${patch}'"
-    bad_patches+=("${patch}")
+    bad_files+=("${patch}")
     return 1
   fi
 
@@ -89,7 +94,7 @@ patch_validate() {
     log_debug "Found template for the patch: '${template}'"
   else
     log_error "Missing template for patch '${patch}'"
-    bad_patches+=("${patch}")
+    bad_files+=("${patch}")
     return 1
   fi
 
@@ -129,56 +134,165 @@ patch_apply() {
     else
       log_debug "Patch '${patch}' can be applied"
     fi
-    good_patches+=("${patch}")
+    good_files+=("${patch}")
   else
     log_error "The patch '${patch}' cannot be applied:"
     cat "${patch_output}" >&2
-    bad_patches+=("${patch}")
+    bad_files+=("${patch}")
   fi
 
   rm -f "${patch_output}"
 }
 
-patch_main() {
-  for patch in $(patch_search "$@") ; do
+patch_validate_customtt() {
+  local file="$1"
+  log_debug "Validating customtt: '${file}'"
+
+  if [ ! -f "${file}" ] ; then
+    log_error "Missing customtt file '${file}'"
+    bad_files+=("${file}")
+    return 1
+  fi
+
+  local template="${file%%.customtt*}.tt2"
+
+  if [ -f "${template}" ] ; then
+    log_debug "Found template for the customtt: '${template}'"
+  else
+    log_error "Missing template for customtt '${customtt}'"
+    bad_files+=("${customtt}")
+    return 1
+  fi
+
+  local patchtt="${file//.customtt/.patchtt}"
+  if [ -f "${patchtt}" ] ; then
+    log_debug "Overwriting patchtt '${patchtt}'"
+  else
+    log_debug "Not found patchtt for the customtt: '${patchtt}'"
+  fi
+}
+
+patch_import_customtt() {
+  local customtt_file="$1"
+  local apply="${2:-false}"
+  local template="${customtt_file%%.customtt*}.tt2"
+  local patchtt="${customtt_file//.customtt/.patchtt}"
+
+  local tmp_patchtt
+  tmp_patchtt=$(mktemp)
+  local diff_output
+  diff_output=$(mktemp)
+
+
+  # diff exit status is 0 if inputs are the same, 1 if different, 2 if trouble.
+  log_debug "Generating temporary patchtt '${tmp_patchtt}' from template '${template}' and customtt '${customtt_file}'"
+  case "$(diff -u "${template}" "${customtt_file}" > "${tmp_patchtt}" 2>"${diff_output}" && echo $? || echo $?)" in
+    0)
+      log_error "No difference between customtt '${customtt_file}' and template '${template}' (patchtt is not necessary here, remove or change customtt file)"
+      bad_files+=("${customtt_file}")
+      ;;
+    1)
+      log_debug "Successfully processed diff for customtt '${customtt_file}'"
+      good_files+=("${customtt_file}")
+      ;;
+    2)
+      log_error "Diff failed between template '${template}' and customtt file '${customtt_file}':"
+      cat "${diff_output}" >&2
+      bad_files+=("${customtt_file}")
+      ;;
+    *)
+      log_error "We should not be here. Aborting (better safe then sorry)."
+      exit 1
+      ;;
+  esac
+
+  if "${apply}" ; then
+    log_info "Creating patchtt file '${patchtt}'"
+    log_debug "Removing first 2 lines (filename + date) from 'diff -u' output (due to time changes on '--from-customtt')"
+    tail -n +3 "${tmp_patchtt}" > "${patchtt}"
+  fi
+
+  rm -f "${diff_output}"
+}
+
+patch_import() {
+  declare -a files=($(patch_search "customtt" "$@"))
+
+  log_debug "Validating customtt files"
+  for customtt in "${files[@]}" ; do
+    log_info "Validating customtt '${customtt}'"
+    if patch_validate_customtt "${customtt}" ; then
+      patch_import_customtt "${customtt}" "false"
+    fi
+  done
+
+  if [ "${#bad_files[@]}" != "0" ] ; then
+    log_debug "Aborted here due to failed patch validation above"
+    return
+  fi
+
+  log_debug "Validating patchtt files from customtt"
+  for customtt in "${files[@]}" ; do
+    patch_import_customtt "${customtt}" "true"
+  done
+}
+
+patch_patch() {
+  declare -a files=($(patch_search "patchtt" "$@"))
+
+  for patch in "${files[@]}" ; do
     log_info "Validating patch '${patch}'"
-    patch_validate "${patch}" && patch_apply "${patch}" "false"
+    if patch_validate_patch "${patch}" ; then
+      patch_apply "${patch}" "false"
+    fi
   done
 
-  if [ "${#bad_patches[@]}" != "0" ] ; then
+  if [ "${#bad_files[@]}" != "0" ] ; then
     log_debug "Aborted here due to failed patch validation above"
     return
   fi
 
-  for patch in $(patch_search "$@") ; do
+  for patch in "${files[@]}" ; do
     log_info "Applying patch '${patch}'"
     patch_apply "${patch}" "true"
   done
 }
-## }}}
-
-if [ "${1:-}" = "--help" ]; then
-  patch_help
-  exit 0
-fi
-
-declare -a bad_patches=()
-declare -a good_patches=()
 
-patch_main "$@"
+patch_footer() {
+  local label="$1"
 
-if [ "${#bad_patches[@]}" = "0" ] ; then
-  if [ "${#good_patches[@]}" = "0" ] ; then
-    log_info "No patchtt files found, nothing to patch."
+  if [ "${#bad_files[@]}" = "0" ] ; then
+    if [ "${#good_files[@]}" = "0" ] ; then
+      log_info "No ${label} files found, nothing to patch."
+    else
+      log_info "Requested ${label} operation has finished successfully."
+    fi
   else
-    log_info "Patch operation has finished successfully."
+    log_error "Some operations above finished with an error for the file(s):"
+    bad_files_unique=($(echo "${bad_files[@]}" | tr ' ' '\n' | sort -u))
+    printf '\t%s\n' "${bad_files_unique[@]}"
+    RC=1
   fi
-else
-  log_error "Some operations above finished with an error for the patch(es):"
-  bad_patches_unique=($(echo "${bad_patches[@]}" | tr ' ' '\n' | sort -u))
-  printf '\t%s\n' "${bad_patches_unique[@]}"
-  RC=1
-fi
+}
+## }}}
+
+declare -a bad_files=()
+declare -a good_files=()
+
+case "${1:-}" in
+  "--help")
+    patch_help
+    ;;
+  "--from-customtt")
+    shift # removing '--from-customtt'
+    patch_import "$@"
+    patch_footer "customtt"
+    ;;
+  *)
+    patch_patch "$@"
+    patch_footer "patchtt"
+    ;;
+esac
 
 exit "${RC:-0}"
 

t/test_ngcpcfg_patch.py

@@ -5,6 +5,9 @@ import pytest
 import re
 import tempfile
 
+###############################################################################
+# tests for "ngcpcfg patch" (no options provides)
+###############################################################################
 
 @pytest.mark.tt_24920
 def test_patch_action_no_args(ngcpcfgcli, tmpdir):
@@ -19,7 +22,7 @@ def test_patch_action_no_args(ngcpcfgcli, tmpdir):
 
 @pytest.mark.tt_24920
 def test_patch_action_help(ngcpcfgcli, tmpdir):
-    # ensure 'ngcpcfg patch' assert on corrupted patchtt file
+    # ensure 'ngcpcfg patch --help' works as expected
 
     template_path = tmpdir.join('/etc')
     apt_path = template_path.join('/apt/apt.conf.d')
@@ -50,7 +53,7 @@ APT::Install-Recommends "0";
 
     assert "'ngcpcfg patch' walks through all templates" in out.stdout
     assert "Validating patch" not in out.stdout
-    assert 'Patch operation has finished successfully.' not in out.stdout
+    assert 'Requested patchtt operation has finished successfully.' not in out.stdout
     assert out.stderr == "b''"
 
 
@@ -87,7 +90,7 @@ APT::Install-Recommends "0";
 
     assert "Validating patch '" + str(template_path) + \
         "/apt/apt.conf.d/71_no_recommended.patchtt.tt2'" in out.stdout
-    assert 'Patch operation has finished successfully.' in out.stdout
+    assert 'Requested patchtt operation has finished successfully.' in out.stdout
     assert out.stderr == "b''"
 
     generated_customtt = str(tmpdir) + \
@@ -134,8 +137,8 @@ APT::Install-Recommends "0";
         "/apt/apt.conf.d/71_no_recommended.patchtt.tt2'" in out.stdout
     assert "Error: The patch '" + str(template_path) + \
         "/apt/apt.conf.d/71_no_recommended.patchtt.tt2' cannot be applied" in out.stderr
-    assert "Error: Some operations above finished with an error for the patch(es)" in out.stderr
-    assert 'Patch operation has finished successfully.' not in out.stdout
+    assert "Error: Some operations above finished with an error for the file(s)" in out.stderr
+    assert 'Requested patchtt operation has finished successfully.' not in out.stdout
 
     # TODO: ensure no customtt.tt2 were generated
 
@@ -154,7 +157,7 @@ def test_patch_action_template_missing_for_patchtt(ngcpcfgcli, tmpdir):
 @@ -1,2 +1 @@
 -
 -the changes here
-+doesn't matter as not tt2 file available
++doesn't matter as no tt2 file available
 ''')
 
     out = ngcpcfgcli("patch",
@@ -171,8 +174,8 @@ def test_patch_action_template_missing_for_patchtt(ngcpcfgcli, tmpdir):
         "/apt/apt.conf.d/71_no_recommended.patchtt.tt2'" in out.stdout
     assert "Error: Missing template for patch '" + str(template_path) + \
         "/apt/apt.conf.d/71_no_recommended.patchtt.tt2'" in out.stderr
-    assert "Error: Some operations above finished with an error for the patch(es)" in out.stderr
-    assert 'Patch operation has finished successfully.' not in out.stdout
+    assert "Error: Some operations above finished with an error for the file(s)" in out.stderr
+    assert 'Requested patchtt operation has finished successfully.' not in out.stdout
 
 
 @pytest.mark.tt_24920
@@ -226,7 +229,72 @@ APT::Install-Recommends "0";
     assert "Successfully created '" + str(template_path) + \
         "/apt/apt.conf.d/71_no_recommended.customtt.tt2'" in out.stdout
     assert '72_another_file.customtt.tt2' not in out.stdout
-    assert 'Patch operation has finished successfully.' in out.stdout
+    assert 'Requested patchtt operation has finished successfully.' in out.stdout
+    assert out.stderr == "b''"
+
+    generated_customtt = str(tmpdir) + \
+        '/etc/apt/apt.conf.d/71_no_recommended.customtt.tt2'
+
+    assert os.path.isfile(generated_customtt)
+    with open(generated_customtt) as customtt:
+        customtt_output = customtt.read()
+    assert customtt_output == '''APT::Install-Recommends "1";\n'''
+    # TODO ensure file '/etc/apt/apt.conf.d/72_another_file.tt2' was not created
+
+
+@pytest.mark.tt_24920
+def test_patch_action_generate_requested_customtt_only_shortname(ngcpcfgcli, tmpdir):
+    # ensure 'ngcpcfg patch .../some.patchtt.tt2' will build one
+    # requested patchtt only using the short filename
+
+    template_path = tmpdir.join('/etc')
+    apt_path = template_path.join('/apt/apt.conf.d')
+    os.makedirs(str(apt_path), exist_ok=True)
+
+    apt_path.join('71_no_recommended.tt2').write('''
+APT::Install-Recommends "0";
+''')
+
+    apt_path.join("71_no_recommended.patchtt.tt2").write('''
+--- 71_no_recommended.tt2.orig  2017-12-08 13:31:49.763402557 +0100
++++ 71_no_recommended.tt2       2017-12-08 13:32:00.559382702 +0100
+@@ -1,2 +1 @@
+-
+-APT::Install-Recommends "0";
++APT::Install-Recommends "1";
+''')
+
+    apt_path.join('72_another_file.tt2').write('''
+# This is a dummy message you should not see
+''')
+
+    apt_path.join("72_another_file.patchtt.tt2").write('''
+--- 71_no_recommended.tt2.orig  2017-12-08 13:31:49.763402557 +0100
++++ 71_no_recommended.tt2       2017-12-08 13:32:00.559382702 +0100
+@@ -1,2 +1 @@
+-
+-# This is a dummy message you should not see
++# This is a dummy message you should not see on 'ngcpcfg build'
+''')
+
+    out = ngcpcfgcli("patch",
+                     "71_no_recommended.patchtt.tt2",
+                     env={
+                         'NGCP_BASE_TT2': os.getcwd(),
+                         'NGCP_PORTFILE': '/tmp/ngcpcfg.port',
+                         'OUTPUT_DIRECTORY': str(tmpdir),
+                         'TEMPLATE_POOL_BASE': str(tmpdir),
+                         'CONFIG_POOL': '/etc',
+                         })
+
+    assert "Validating patch '" + str(template_path) + \
+        "/apt/apt.conf.d/71_no_recommended.patchtt.tt2'" in out.stdout
+    assert "Applying patch '" + str(template_path) + \
+        "/apt/apt.conf.d/71_no_recommended.patchtt.tt2'" in out.stdout
+    assert "Successfully created '" + str(template_path) + \
+        "/apt/apt.conf.d/71_no_recommended.customtt.tt2'" in out.stdout
+    assert '72_another_file.customtt.tt2' not in out.stdout
+    assert 'Requested patchtt operation has finished successfully.' in out.stdout
     assert out.stderr == "b''"
 
     generated_customtt = str(tmpdir) + \
@@ -269,15 +337,18 @@ APT::Install-Recommends "0";
 def test_patch_action_build_generate_and_overwrite_customtt_file(ngcpcfgcli, tmpdir):
     # Ensure here "ngcpcfg build" will:
     #   * find available patchtt file
-    #   * validate available patchtt file
+    #   * validate available patchtt file (necessary only)
     #   * use available patchtt file
-    #   * generate proper customtt file using tt2 + patchtt
-    #   * overwrite old/available customtt file
-    #   * build proper config using new customtt file
+    #   * care about patchtt.tt2.sp1 file
+    #   * generate proper customtt files using tt2 + patchtt
+    #   * overwrite old/available customtt files
+    #   * build proper config using new customtt files
 
     template_path = tmpdir.join('/etc')
     apt_path = template_path.join('/apt/apt.conf.d')
+    dummy_path = template_path.join('/dummy')
     os.makedirs(str(apt_path), exist_ok=True)
+    os.makedirs(str(dummy_path), exist_ok=True)
 
     apt_path.join('71_no_recommended.tt2').write('''
 APT::Install-Recommends "0";
@@ -288,6 +359,10 @@ APT::Install-Recommends "0";
 APT::Install-Recommends "2";
 ''')
 
+    expected_output = '''
+APT::Install-Recommends "1";
+'''
+
     apt_path.join("71_no_recommended.patchtt.tt2").write('''
 --- 71_no_recommended.tt2.orig   2018-01-10 15:24:06.951855880 +0100
 +++ 71_no_recommended.tt2        2018-01-10 15:27:14.891237633 +0100
@@ -297,9 +372,36 @@ APT::Install-Recommends "2";
 
 ''')
 
-    expected_output = '''
+    apt_path.join('71_no_recommended.customtt.tt2.sp1').write('''
+# generated via customtt.sp1 without patch file
+APT::Install-Recommends "3";
+''')
+
+    apt_path.join("71_no_recommended.patchtt.tt2.sp1").write('''
+@@ -1 +1 @@
+-APT::Install-Recommends "0";
++APT::Install-Recommends "3";
+
+''')
+
+    expected_output_sp1 = '''
 APT::Install-Recommends "1";
 '''
+
+    dummy_path.join('dummy.tt2').write('''
+dome dummy template message
+''')
+
+    dummy_path.join('dummy.customtt.tt2').write('''
+dome dummy customtt message
+''')
+
+    dummy_path.join("dummy.patchtt.tt2").write('''
+@@ -1 +1 @@
+-dome dummy template message
++dome dummy customtt message
+''')
+
     out = ngcpcfgcli("build", "--ignore-branch-check",
                      "/etc/apt/apt.conf.d/",
                      env={
@@ -311,13 +413,20 @@ APT::Install-Recommends "1";
                          })
 
     assert 'No patchtt files found, nothing to patch.' not in out.stdout
+    assert 'dummy' not in out.stdout
     assert "Validating patch '" + str(template_path) + \
         "/apt/apt.conf.d/71_no_recommended.patchtt.tt2'" in out.stdout
+    assert "Validating patch '" + str(template_path) + \
+        "/apt/apt.conf.d/71_no_recommended.patchtt.tt2.sp1'" in out.stdout
     assert "Applying patch '" + str(template_path) + \
         "/apt/apt.conf.d/71_no_recommended.patchtt.tt2'" in out.stdout
     assert "Successfully created '" + str(template_path) + \
         "/apt/apt.conf.d/71_no_recommended.customtt.tt2'" in out.stdout
-    assert 'Patch operation has finished successfully.' in out.stdout
+    assert "Applying patch '" + str(template_path) + \
+        "/apt/apt.conf.d/71_no_recommended.patchtt.tt2.sp1'" in out.stdout
+    assert "Successfully created '" + str(template_path) + \
+        "/apt/apt.conf.d/71_no_recommended.customtt.tt2.sp1'" in out.stdout
+    assert 'Requested patchtt operation has finished successfully.' in out.stdout
     assert "Generating " + str(tmpdir) + "/output/" + str(tmpdir) + \
         "//etc/apt/apt.conf.d/71_no_recommended: OK" in out.stdout
     # disabled for the moment, see https://gerrit.mgm.sipwise.com/#/c/17739/4/t/test_ngcpcfg_patch.py@99
@@ -331,6 +440,136 @@ APT::Install-Recommends "1";
         output = output_file.read()
     assert output == expected_output
 
+    generated_customtt_sp1 = str(template_path) + \
+        '/apt/apt.conf.d/71_no_recommended.customtt.tt2.sp1'
+
+    assert os.path.isfile(generated_customtt)
+    with open(generated_customtt) as output_file:
+        output = output_file.read()
+    assert output == expected_output_sp1
+
+    generated_config = str(tmpdir) + "/output" + str(tmpdir) + \
+        '/etc/apt/apt.conf.d/71_no_recommended'
+
+    assert os.path.isfile(generated_config)
+    with open(generated_config) as output_file:
+        output = output_file.read()
+    assert output == expected_output
+
+
+@pytest.mark.tt_24920
+def test_patch_action_build_generate_all_file(ngcpcfgcli, tmpdir):
+    # the same as test 'test_patch_action_build_generate_and_overwrite_customtt_file'
+    # while build all available files
+
+    template_path = tmpdir.join('/etc')
+    apt_path = template_path.join('/apt/apt.conf.d')
+    dummy_path = template_path.join('/dummy')
+    os.makedirs(str(apt_path), exist_ok=True)
+    os.makedirs(str(dummy_path), exist_ok=True)
+
+    apt_path.join('71_no_recommended.tt2').write('''
+APT::Install-Recommends "0";
+''')
+
+    apt_path.join('71_no_recommended.customtt.tt2').write('''
+# generated via customtt without patch file
+APT::Install-Recommends "2";
+''')
+
+    expected_output = '''
+APT::Install-Recommends "1";
+'''
+
+    apt_path.join("71_no_recommended.patchtt.tt2").write('''
+--- 71_no_recommended.tt2.orig   2018-01-10 15:24:06.951855880 +0100
++++ 71_no_recommended.tt2        2018-01-10 15:27:14.891237633 +0100
+@@ -1 +1 @@
+-APT::Install-Recommends "0";
++APT::Install-Recommends "1";
+
+''')
+
+    apt_path.join('71_no_recommended.customtt.tt2.sp1').write('''
+# generated via customtt.sp1 without patch file
+APT::Install-Recommends "3";
+''')
+
+    apt_path.join("71_no_recommended.patchtt.tt2.sp1").write('''
+@@ -1 +1 @@
+-APT::Install-Recommends "0";
++APT::Install-Recommends "3";
+
+''')
+
+    expected_output_sp1 = '''
+APT::Install-Recommends "1";
+'''
+
+    dummy_path.join('dummy.tt2').write('''
+dome dummy template message
+''')
+
+    dummy_path.join('dummy.customtt.tt2').write('''
+dome dummy customtt message
+''')
+
+    dummy_path.join("dummy.patchtt.tt2").write('''
+@@ -1 +1 @@
+-dome dummy template message
++dome dummy customtt message
+''')
+
+    out = ngcpcfgcli("build", "--ignore-branch-check",
+                     env={
+                         'NGCP_BASE_TT2': os.getcwd(),
+                         'NGCP_PORTFILE': '/tmp/ngcpcfg.port',
+                         'OUTPUT_DIRECTORY': str(tmpdir) + "/output",
+                         'TEMPLATE_POOL_BASE': str(tmpdir),
+                         'CONFIG_POOL': '/etc',
+                         })
+
+    assert 'No patchtt files found, nothing to patch.' not in out.stdout
+    assert "Validating patch '" + str(template_path) + \
+        "/apt/apt.conf.d/71_no_recommended.patchtt.tt2'" in out.stdout
+    assert "Validating patch '" + str(template_path) + \
+        "/apt/apt.conf.d/71_no_recommended.patchtt.tt2.sp1'" in out.stdout
+    assert "Validating patch '" + str(template_path) + \
+        "/dummy/dummy.patchtt.tt2'" in out.stdout
+    assert "Applying patch '" + str(template_path) + \
+        "/apt/apt.conf.d/71_no_recommended.patchtt.tt2'" in out.stdout
+    assert "Successfully created '" + str(template_path) + \
+        "/apt/apt.conf.d/71_no_recommended.customtt.tt2'" in out.stdout
+    assert "Applying patch '" + str(template_path) + \
+        "/apt/apt.conf.d/71_no_recommended.patchtt.tt2.sp1'" in out.stdout
+    assert "Successfully created '" + str(template_path) + \
+        "/apt/apt.conf.d/71_no_recommended.customtt.tt2.sp1'" in out.stdout
+    assert "Applying patch '" + str(template_path) + \
+        "/dummy/dummy.patchtt.tt2'" in out.stdout
+    assert "Successfully created '" + str(template_path) + \
+        "/dummy/dummy.customtt.tt2'" in out.stdout
+    assert 'Requested patchtt operation has finished successfully.' in out.stdout
+    assert "Generating " + str(tmpdir) + "/output/" + str(tmpdir) + \
+        "//etc/apt/apt.conf.d/71_no_recommended: OK" in out.stdout
+    # disabled for the moment, see https://gerrit.mgm.sipwise.com/#/c/17739/4/t/test_ngcpcfg_patch.py@99
+    #assert out.stderr == "b''"
+
+    generated_customtt = str(template_path) + \
+        '/apt/apt.conf.d/71_no_recommended.customtt.tt2'
+
+    assert os.path.isfile(generated_customtt)
+    with open(generated_customtt) as output_file:
+        output = output_file.read()
+    assert output == expected_output
+
+    generated_customtt_sp1 = str(template_path) + \
+        '/apt/apt.conf.d/71_no_recommended.customtt.tt2.sp1'
+
+    assert os.path.isfile(generated_customtt)
+    with open(generated_customtt) as output_file:
+        output = output_file.read()
+    assert output == expected_output_sp1
+
     generated_config = str(tmpdir) + "/output" + str(tmpdir) + \
         '/etc/apt/apt.conf.d/71_no_recommended'
 
@@ -372,7 +611,7 @@ APT::Install-Recommends "1";
                          })
 
     assert 'No patchtt files found, nothing to patch.' in out.stdout
-    assert 'Patch operation has finished successfully.' not in out.stdout
+    assert 'Requested patchtt operation has finished successfully.' not in out.stdout
     assert 'Generating ' in out.stdout
     assert '/etc/apt/apt.conf.d/71_no_recommended: OK' in out.stdout
     assert 'Validating patch' not in out.stdout
@@ -424,7 +663,183 @@ APT::Install-Recommends "0";
         "/apt/apt.conf.d/71_no_recommended.patchtt.tt2'" in out.stdout
     assert "Error: The patch '" + str(template_path) + \
         "/apt/apt.conf.d/71_no_recommended.patchtt.tt2' cannot be applied" in out.stderr
-    assert "Error: Some operations above finished with an error for the patch(es)" in out.stderr
-    assert 'Patch operation has finished successfully.' not in out.stdout
+    assert "Error: Some operations above finished with an error for the file(s)" in out.stderr
+    assert 'Requested patchtt operation has finished successfully.' not in out.stdout
     assert 'Generating ' not in out.stdout
     assert '/etc/apt/apt.conf.d/71_no_recommended: OK' not in out.stdout
+
+
+###############################################################################
+# tests for "ngcpcfg patch --from-customtt"
+###############################################################################
+
+
+@pytest.mark.tt_24920
+def test_patch_action_from_customtt_files(ngcpcfgcli, tmpdir):
+    # Ensure here "ngcpcfg patch --from-customtt" will:
+    #   * find all available customtt file
+    #   * create all necessary patchtt files
+
+    template_path = tmpdir.join('/etc')
+    apt_path = template_path.join('/apt/apt.conf.d')
+    os.makedirs(str(apt_path), exist_ok=True)
+
+    apt_path.join('71_no_recommended.tt2').write('''
+# some comment
+APT::Install-Recommends "0";
+''')
+
+    apt_path.join('71_no_recommended.customtt.tt2').write('''
+# some comment
+APT::Install-Recommends "2";
+''')
+
+    template_path.join('expected_patch.diff').write('''@@ -1,3 +1,3 @@
+ 
+ # some comment
+-APT::Install-Recommends "0";
++APT::Install-Recommends "2";
+''')
+
+    out = ngcpcfgcli("patch", "--from-customtt",
+                     env={
+                         'NGCP_BASE_TT2': os.getcwd(),
+                         'NGCP_PORTFILE': '/tmp/ngcpcfg.port',
+                         'OUTPUT_DIRECTORY': str(tmpdir) + "/output",
+                         'TEMPLATE_POOL_BASE': str(tmpdir),
+                         'CONFIG_POOL': '/etc',
+                         })
+
+    assert 'No patchtt files found, nothing to patch.' not in out.stdout
+    assert "Validating customtt '" + str(template_path) + \
+        "/apt/apt.conf.d/71_no_recommended.customtt.tt2'" in out.stdout
+    assert "Creating patchtt file '" + str(template_path) + \
+        "/apt/apt.conf.d/71_no_recommended.patchtt.tt2'" in out.stdout
+    assert 'Requested customtt operation has finished successfully.' in out.stdout
+    # disabled for the moment, see https://gerrit.mgm.sipwise.com/#/c/17739/4/t/test_ngcpcfg_patch.py@99
+    #assert out.stderr == "b''"
+
+    generated_patchtt = str(template_path) + \
+        '/apt/apt.conf.d/71_no_recommended.patchtt.tt2'
+    expected_patchtt = str(template_path) + \
+        '/expected_patch.diff'
+
+    assert os.path.isfile(generated_patchtt)
+    assert os.path.isfile(expected_patchtt)
+    with open(generated_patchtt) as output_file:
+        output = output_file.read()
+    with open(expected_patchtt) as expected_file:
+        expected = expected_file.read()
+    assert output == expected
+
+
+@pytest.mark.tt_24920
+def test_patch_action_from_customtt_missing_file_argument(ngcpcfgcli, tmpdir):
+    # ensure "ngcpcfg patch --from-customtt missing.customtt.tt2" will be handled properly if
+    # no some.customtt.tt2 file are available
+
+    out = ngcpcfgcli("patch",
+                     "--from-customtt",
+                     "missing.customtt.tt2",
+                     env={
+                         'NGCP_BASE_TT2': os.getcwd(),
+                         'NGCP_PORTFILE': '/tmp/ngcpcfg.port',
+                         'OUTPUT_DIRECTORY': str(tmpdir),
+                         'TEMPLATE_POOL_BASE': str(tmpdir),
+                         'CONFIG_POOL': '/etc',
+                         })
+
+    assert 'No customtt files found, nothing to patch.' in out.stdout
+    assert "Creating patchtt file '" not in out.stdout
+    # disabled for the moment, see https://gerrit.mgm.sipwise.com/#/c/17739/4/t/test_ngcpcfg_patch.py@99
+    #assert out.stderr == "b''"
+
+
+@pytest.mark.tt_24920
+def test_patch_action_from_customtt_filename_only(ngcpcfgcli, tmpdir):
+    # ensure "ngcpcfg patch --from-customtt valid.customtt.tt2" will be handled properly if
+    # no filename only valid.customtt.tt2 has been passed instead of full path
+
+    template_path = tmpdir.join('/etc')
+    apt_path = template_path.join('/apt/apt.conf.d')
+    os.makedirs(str(apt_path), exist_ok=True)
+
+    apt_path.join('71_no_recommended.tt2').write('''
+# some comment
+APT::Install-Recommends "0";
+''')
+
+    apt_path.join('71_no_recommended.customtt.tt2').write('''
+# some comment
+APT::Install-Recommends "2";
+''')
+
+    template_path.join('expected_patch.diff').write('''@@ -1,3 +1,3 @@
+ 
+ # some comment
+-APT::Install-Recommends "0";
++APT::Install-Recommends "2";
+''')
+
+    out = ngcpcfgcli("patch",
+                     "--from-customtt",
+                     "71_no_recommended.customtt.tt2",
+                     env={
+                         'NGCP_BASE_TT2': os.getcwd(),
+                         'NGCP_PORTFILE': '/tmp/ngcpcfg.port',
+                         'OUTPUT_DIRECTORY': str(tmpdir),
+                         'TEMPLATE_POOL_BASE': str(tmpdir),
+                         'CONFIG_POOL': '/etc',
+                         })
+
+    assert 'No patchtt files found, nothing to patch.' not in out.stdout
+    assert "Validating customtt '" + str(template_path) + \
+        "/apt/apt.conf.d/71_no_recommended.customtt.tt2'" in out.stdout
+    assert "Creating patchtt file '" + str(template_path) + \
+        "/apt/apt.conf.d/71_no_recommended.patchtt.tt2'" in out.stdout
+    assert 'Requested customtt operation has finished successfully.' in out.stdout
+    # disabled for the moment, see https://gerrit.mgm.sipwise.com/#/c/17739/4/t/test_ngcpcfg_patch.py@99
+    #assert out.stderr == "b''"
+
+    generated_patchtt = str(template_path) + \
+        '/apt/apt.conf.d/71_no_recommended.patchtt.tt2'
+    expected_patchtt = str(template_path) + \
+        '/expected_patch.diff'
+
+    assert os.path.isfile(generated_patchtt)
+    assert os.path.isfile(expected_patchtt)
+    with open(generated_patchtt) as output_file:
+        output = output_file.read()
+    with open(expected_patchtt) as expected_file:
+        expected = expected_file.read()
+    assert output == expected
+
+
+@pytest.mark.tt_24920
+def test_patch_action_from_customtt_missing_templates(ngcpcfgcli, tmpdir):
+    # ensure "ngcpcfg patch --from-customtt" will be aborted if template is missing for customtt
+
+    template_path = tmpdir.join('/etc')
+    apt_path = template_path.join('/apt/apt.conf.d')
+    os.makedirs(str(apt_path), exist_ok=True)
+
+    apt_path.join("71_no_recommended.customtt.tt2").write('''
+the content here doesn't matter as no tt2 file available
+''')
+
+    out = ngcpcfgcli("patch",
+                     "--from-customtt",
+                     env={
+                         'NGCP_BASE_TT2': os.getcwd(),
+                         'NGCP_PORTFILE': '/tmp/ngcpcfg.port',
+                         'OUTPUT_DIRECTORY': str(tmpdir),
+                         'TEMPLATE_POOL_BASE': str(tmpdir),
+                         'CONFIG_POOL': '/etc',
+                         })
+
+    assert "Validating customtt '" + str(template_path) + \
+        "/apt/apt.conf.d/71_no_recommended.customtt.tt2'" in out.stdout
+    assert "Error: Missing template for customtt '" + str(template_path) + \
+        "/apt/apt.conf.d/71_no_recommended.customtt.tt2'" in out.stderr
+    assert "Error: Some operations above finished with an error for the file(s)" in out.stderr
+    assert 'Requested patchtt operation has finished successfully.' not in out.stdout