From 4eafabb37af78f86beec3ce129879870b2533d2e Mon Sep 17 00:00:00 2001
From: Sven Klemm <sven@timescale.com>
Date: Thu, 30 Jul 2020 17:25:56 +0200
Subject: [PATCH] Fix telemetry installed_time format

This patch changes the telemetry code to always send the installed_time
timestamp AS ISO8601. Previously it was depending on local settings
leading to timestamps not processable by the telemetry receiver.
---
 src/telemetry/telemetry.c   | 13 ++++++++++---
 test/expected/telemetry.out | 14 ++++++++++++++
 test/sql/telemetry.sql      | 13 +++++++++++++
 3 files changed, 37 insertions(+), 3 deletions(-)

diff --git a/src/telemetry/telemetry.c b/src/telemetry/telemetry.c
index c83196ed1df..80b362893bd 100644
--- a/src/telemetry/telemetry.c
+++ b/src/telemetry/telemetry.c
@@ -296,6 +296,15 @@ get_pgversion_string()
 	return buf->data;
 }
 
+#define ISO8601_FORMAT "YYYY-MM-DD\"T\"HH24:MI:SSOF"
+
+static char *
+format_iso8601(Datum value)
+{
+	return TextDatumGetCString(
+		DirectFunctionCall2(timestamptz_to_char, value, CStringGetTextDatum(ISO8601_FORMAT)));
+}
+
 static StringInfo
 build_version_body(void)
 {
@@ -320,9 +329,7 @@ build_version_body(void)
 						 DirectFunctionCall1(uuid_out, ts_telemetry_metadata_get_exported_uuid())));
 	ts_jsonb_add_str(parse_state,
 					 REQ_INSTALL_TIME,
-					 DatumGetCString(
-						 DirectFunctionCall1(timestamptz_out,
-											 ts_telemetry_metadata_get_install_timestamp())));
+					 format_iso8601(ts_telemetry_metadata_get_install_timestamp()));
 
 	ts_jsonb_add_str(parse_state, REQ_INSTALL_METHOD, TIMESCALEDB_INSTALL_METHOD);
 
diff --git a/test/expected/telemetry.out b/test/expected/telemetry.out
index 00cc4715b0e..4c9c878009e 100644
--- a/test/expected/telemetry.out
+++ b/test/expected/telemetry.out
@@ -491,3 +491,17 @@ SELECT json_object_field(get_telemetry_report()::json,'num_hypertables');
  "1"
 (1 row)
 
+set datestyle to iso;
+-- check that installed_time formatting in telemetry report does not depend on local date settings
+SELECT json_object_field_text(get_telemetry_report()::json,'installed_time') as installed_time
+\gset
+set datestyle to sql;
+SELECT json_object_field_text(get_telemetry_report()::json,'installed_time') as installed_time2
+\gset
+SELECT :'installed_time' = :'installed_time2' AS equal, length(:'installed_time'), length(:'installed_time2');
+ equal | length | length 
+-------+--------+--------
+ t     |     22 |     22
+(1 row)
+
+RESET datestyle;
diff --git a/test/sql/telemetry.sql b/test/sql/telemetry.sql
index 30b56f20d27..5af10115a38 100644
--- a/test/sql/telemetry.sql
+++ b/test/sql/telemetry.sql
@@ -187,3 +187,16 @@ CREATE TABLE device_readings (
 SELECT table_name FROM create_hypertable('device_readings', 'observation_time');
 
 SELECT json_object_field(get_telemetry_report()::json,'num_hypertables');
+
+set datestyle to iso;
+-- check that installed_time formatting in telemetry report does not depend on local date settings
+SELECT json_object_field_text(get_telemetry_report()::json,'installed_time') as installed_time
+\gset
+set datestyle to sql;
+SELECT json_object_field_text(get_telemetry_report()::json,'installed_time') as installed_time2
+\gset
+
+SELECT :'installed_time' = :'installed_time2' AS equal, length(:'installed_time'), length(:'installed_time2');
+
+RESET datestyle;
+