(SUP-2372) add pg_repack schema reset task (#53)

* (SUP-2372) reset pgrepack task added

Co-authored-by: martyewings <martyewings@gmail.com>

Author: pgrant87

README.md

@@ -111,6 +111,16 @@ This module provides cron jobs to VACUUM FULL tables in the `pe-puppetdb` databa
 
 With PE 2018.1.7 and 2019.0.2 and newer, this module uses `pg_repack` instead of `VACUUM FULL`.
 
+Please note that when using `pg_repack` as part of the pe_databases module, unclean exits can leave behind the schema when otherwise it should have been cleaned up. This can result in the messages similar to the following:
+
+```
+INFO: repacking table "public.fact_paths"
+WARNING: the table "public.fact_paths" already has a trigger called "repack_trigger"
+DETAIL: The trigger was probably installed during a previous attempt to run pg_repack on the table which was interrupted and for some reason failed to clean up the temporary objects. Please drop the trigger or drop and recreate the pg_repack extension altogether to remove all the temporary objects left over.
+```
+
+The module now contains a task `reset_pgrepack_schema` to mitigate this issue. This needs to be run against your Primary or Postgrsql server to resolve this and it will drop and recreate the extension, removing the temporary objects.
+
 ### Vacuuming
 
 Generally speaking, PostgreSQL keeps itself in good shape with a process called [auto vacuuming](https://www.postgresql.org/docs/11/runtime-config-autovacuum.html).

files/common.sh

@@ -0,0 +1,37 @@
+#!/bin/bash
+
+# TODO: helper task?
+
+# Exit with an error message and error code, defaulting to 1
+fail() {
+  # Print a stderr: entry if there were anything printed to stderr
+  if [[ -s $_tmp ]]; then
+    # Hack to try and output valid json by replacing newlines with spaces.
+    echo "{ \"status\": \"error\", \"message\": \"$1\", \"stderr\": \"$(tr '\n' ' ' <$_tmp)\" }"
+  else
+    echo "{ \"status\": \"error\", \"message\": \"$1\" }"
+  fi
+
+  exit ${2:-1}
+}
+
+success() {
+  echo "$1"
+  exit 0
+}
+
+# Test for colors. If unavailable, unset variables are ok
+if tput colors &>/dev/null; then
+  green="$(tput setaf 2)"
+  red="$(tput setaf 1)"
+  reset="$(tput sgr0)"
+fi
+
+_tmp="$(mktemp)"
+exec 2>>"$_tmp"
+
+# Use indirection to munge PT_ environment variables
+# e.g. "$PT_version" becomes "$version"
+for v in ${!PT_*}; do
+  declare "${v#*PT_}"="${!v}"
+done

tasks/reset_pgrepack_schema.json

@@ -0,0 +1,8 @@
+{
+  "puppet_task_version": 1,
+  "supports_noop": false,
+  "description": "This task will remove and recreate the pg_repack extension",
+  "implementations": [
+    {"name": "reset_pgrepack_schema.sh", "requirements": ["shell"], "files": ["pe_databases/files/common.sh"], "input_method": "environment"}
+  ]
+}

tasks/reset_pgrepack_schema.sh

@@ -0,0 +1,20 @@
+#!/bin/sh
+
+# Puppet Task Name: reset_pgrepack_schema
+declare PT__installdir
+# shellcheck disable=SC1090
+source "$PT__installdir/pe_databases/files/common.sh"
+
+#Determine if PE Postgres is available
+if puppet resource service pe-postgresql | grep -q running; then
+    #Remove the pg_repack extension
+    su - pe-postgres -s '/bin/bash' -c '/opt/puppetlabs/server/bin/psql -d pe-puppetdb -c "DROP EXTENSION pg_repack CASCADE"' || fail "unable to drop pg_repack extension"
+
+    #Then, recreate the pg_repack extension
+    su - pe-postgres -s '/bin/bash' -c '/opt/puppetlabs/server/bin/psql -d pe-puppetdb -c "CREATE EXTENSION pg_repack"' || fail "unable to create pg_repack estenstion"
+else
+  fail "No running PE-PostgreSQL instance found, please run this task against your Primary or PE-PostgreSQL server"
+fi
+
+
+success '{ "status": "success" }'