From 68be86349b3089e21c8e7299ec7c5cb43a637461 Mon Sep 17 00:00:00 2001
From: Ian Barwick <ian@2ndquadrant.com>
Date: Tue, 6 Aug 2019 20:50:27 +0900
Subject: [PATCH] Add function to parse version string returned by "repmgr
 --version"

---
 repmgr.h   |  1 +
 sysutils.c | 41 +++++++++++++++++++++++++++++++++++++++++
 sysutils.h |  1 +
 3 files changed, 43 insertions(+)

diff --git a/repmgr.h b/repmgr.h
index 23f3ec17..d99032af 100644
--- a/repmgr.h
+++ b/repmgr.h
@@ -51,6 +51,7 @@
 
 #define UNKNOWN_SERVER_VERSION_NUM -1
 #define UNKNOWN_BDR_VERSION_NUM -1
+#define UNKNOWN_REPMGR_VERSION_NUM -1
 
 #define UNKNOWN_TIMELINE_ID -1
 #define UNKNOWN_SYSTEM_IDENTIFIER 0
diff --git a/sysutils.c b/sysutils.c
index 929cb08e..96772f53 100644
--- a/sysutils.c
+++ b/sysutils.c
@@ -364,3 +364,44 @@ enable_wal_receiver(PGconn *conn, bool wait_startup)
 
 	return wal_receiver_pid;
 }
+
+
+/**
+ * Parse the string returned by "repmgr --version", e.g. "repmgr 4.1.2",
+ * and return it as a version integer (e.g. 40102).
+ *
+ * This is required for backwards compatibility as versions prior to
+ * 4.3 do not have the --version-number option.
+ */
+int
+parse_repmgr_version(const char *version_string)
+{
+	int series, major, minor;
+	int version_integer = UNKNOWN_REPMGR_VERSION_NUM;
+	PQExpBufferData sscanf_string;
+
+	initPQExpBuffer(&sscanf_string);
+
+	appendPQExpBuffer(&sscanf_string, "%s ",
+					  progname());
+	appendPQExpBufferStr(&sscanf_string, "%i.%i.%i");
+
+	if (sscanf(version_string, sscanf_string.data, &series, &major, &minor) == 3)
+	{
+		version_integer = (series * 10000) + (major * 100) + minor;
+	}
+	else
+	{
+		resetPQExpBuffer(&sscanf_string);
+		appendPQExpBuffer(&sscanf_string, "%s ",
+						  progname());
+		appendPQExpBufferStr(&sscanf_string, "%i.%i");
+
+		if (sscanf(version_string, "repmgr %i.%i", &series, &major) == 2)
+		{
+			version_integer = (series * 10000) + (major * 100);
+		}
+	}
+
+	return version_integer;
+}
diff --git a/sysutils.h b/sysutils.h
index 6c046920..cc358f67 100644
--- a/sysutils.h
+++ b/sysutils.h
@@ -28,5 +28,6 @@ extern bool remote_command(const char *host, const char *user, const char *comma
 extern pid_t disable_wal_receiver(PGconn *conn);
 extern pid_t enable_wal_receiver(PGconn *conn, bool wait_startup);
 
+extern int parse_repmgr_version(const char *version_string);
 
 #endif							/* _SYSUTILS_H_ */