Merge pull request #37 from coopdevs/promtail-one-line-logs

Promtail-friendly one line logs

CHANGELOG.md

@@ -6,6 +6,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+- Print promtail-friendly logs. See [#37](https://github.com/coopdevs/backups_role/pull/37)
+
 ## [v1.2.4] - 2019-12-03
 
 ### Fixed

templates/cron-main.sh.j2

@@ -3,40 +3,45 @@
 # Exit with error code 1 if any command fails
 set -e
 
-# Clone standard output to standard error
-#+ This way we have titles and datetimes in both outputs: err and out
-#+ and therefore error messages appear within a context.
-#+ In Linux this is equivalent to /dev/std{out,err}
-#+ that sounds more intuitive, but it's not as portable.
-#+ See https://unix.stackexchange.com/a/123659
-
-# Use `tee -a` to append error logs instead of overwritting
-# It is interpreted before the later append stderr redirection `2>>`
-#+ Example:
-#+     for i in 1 2 3; do { date | tee /dev/fd/2; } >> out.log 2>> err.log ; done
-#+ err.log has only one line, while out.log has three.
-
-function title {
-  echo -e "\n## $1 ##" | tee -a /dev/fd/2;
-  date | tee -a /dev/fd/2;
+# Output to stdout the message given, escaping its newlines and prefixing with date and loglevel
+function log {
+  LOGLEVEL=${LOGLEVEL:-INFO}
+  ARGS="$@"
+  echo "$(date --rfc-3339=ns) | $LOGLEVEL | ${ARGS//$'\n'/\\n}"
 }
 
 # Remove temporal directory
 function clean {
   rm -rf "{{ backups_role_tmp_path }}"
 }
 
+# Runner that saves stderr and logs it if command fails
+function run {
+
+  set +e
+  ERR_S=$(eval "$@" 2>&1 1>/dev/null)
+  ERR_C=$?
+  set -e
+
+  if [ $ERR_C -ne 0 ]; then
+    export LOGLEVEL="ERROR"
+    log "$ERR_S"
+    exit $ERR_C
+  fi
+}
+
 # Set up an exit trap to delete temporal directory
 #+ before exiting, even if there are errors.
 trap clean EXIT
 
-title "Create temporal directory"
-mkdir -p "{{ backups_role_tmp_path }}"
-echo "…done"
+log "Create temporal directory"
+run mkdir -p "{{ backups_role_tmp_path }}"
 
 # Execute scripts in chain if error code is ok
 {# Append and render script template to prepare backup #}
 {% include backups_role_script_prepare_template %}
 
 {# Append and render script template to upload backup #}
 {% include "cron-upload.sh.j2" %}
+
+log "Backup complete"

templates/cron-prepare.sh.j2

@@ -1,11 +1,6 @@
 {# This template is included by cron-main.sh.j2 #}
-# NOTE
-# This script is meant to be executed by a very limited sudoer user.
-# It must be allowed to only execute `tar -czvf *` as root,
-# meaning that it can't uncompress, add options, or even change the options order.
-# This is a way to give to this user read-only access to whole filesystem.
 
-title "Postgres DB dump"
+log "Postgres DB dump"
 {# jinja comment.
  Next non-comment line below should render to something like:
  for DB in "main" "secondary" "test"; do
@@ -18,10 +13,13 @@ title "Postgres DB dump"
  https://stackoverflow.com/a/49692186/3625897
 #}
 for DB in "{{ backups_role_db_names | join('" "')  }}"; do
-  /usr/bin/pg_dump --encoding=UTF8 "$DB" > "{{ backups_role_tmp_path }}/pg_dump_$DB"
+  run /usr/bin/pg_dump --encoding=UTF8 "$DB" > "{{ backups_role_tmp_path }}/pg_dump_$DB"
 done
-echo "…done"
 
-title "Compress assets data"
-sudo tar -czvf {{ backups_role_tmp_path }}/assets.tar.gz {{ backups_role_assets_paths|join(' ') }}
-echo "…done"
+# This command below is meant to be executed by a very limited sudoer user.
+# It must be allowed to only execute `tar -czvf *` as root,
+# meaning that it can't uncompress, add options, or even change the options order.
+# This is a way to give to this user read-only access to whole filesystem.
+
+log "Compress assets data"
+run sudo tar -czvf {{ backups_role_tmp_path }}/assets.tar.gz {{ backups_role_assets_paths|join(' ') }}

templates/cron-upload.sh.j2

@@ -1,26 +1,23 @@
 {# This template is included by cron-main.sh.j2 #}
-title "Restic backup"
-restic backup \
+
+log "Restic backup"
+run restic backup \
   {% if backups_role_script_prepare_template == "cron-prepare.sh.j2" %}
   {% for db in backups_role_db_names %}
   "{{ backups_role_tmp_path }}/pg_dump_{{ db }}" \
   {% endfor %}
   {% endif %}
   {{ backups_role_assets_paths|join(' ') }}
 
-echo "…done"
-
-title "Restic forget"
-restic forget \
+log "Restic forget"
+run restic forget \
   --keep-last    {{ backups_role_keep_last }} \
   --keep-hourly  {{ backups_role_keep_hourly }} \
   --keep-daily   {{ backups_role_keep_daily }} \
   --keep-weekly  {{ backups_role_keep_weekly }} \
   --keep-monthly {{ backups_role_keep_monthly }} \
   --keep-yearly  {{ backups_role_keep_yearly }} \
   --prune
-echo "…done"
 
-title "Restic check"
-restic check
-echo "…done"
+log "Restic check"
+run restic check