catalog_query.h File Reference

Query the global catalog server for server descriptions. More...

#include <time.h>
#include "jx.h"

Go to the source code of this file.

Functions
struct catalog_query *	catalog_query_create (const char *hosts, struct jx *filter_expr, time_t stoptime)
	Create a catalog query. More...
struct jx *	catalog_query_read (struct catalog_query *q, time_t stoptime)
	Read the next object from a query. More...
void	catalog_query_delete (struct catalog_query *q)
	Delete a completed query object. More...
int	catalog_query_send_update (const char *hosts, const char *text)
	Send update text to the given hosts hosts is a comma delimited list of hosts, each of which can be host or host:port More...
int	catalog_query_send_update_conditional (const char *hosts, const char *text)
	Send update text to the given hosts, but fail if the update text cannot be compressed to a suitable size. More...

Detailed Description

Query the global catalog server for server descriptions.

Function Documentation

struct catalog_query* catalog_query_create	(	const char *	hosts,
		struct jx *	filter_expr,
		time_t	stoptime
	)

Create a catalog query.

Connects to a catalog server, issues a query, and waits for the results. The caller may specify a specific catalog host and port. If none is given, then the environment variables CATALOG_HOST and CATALOG_PORT will be consulted. If neither is set, the system will contact chirp.cse.nd.edu on port 9097.

Parameters

hosts	A comma delimited list of catalog servers to query, or null for the default server.
filter_expr	An optional expression to filter the results in JX syntax. A null pointer indicates no filter.
stoptime	The absolute time at which to abort.

Returns

A catalog query object on success, or null on failure.

struct jx* catalog_query_read	(	struct catalog_query *	q,
		time_t	stoptime
	)

Read the next object from a query.

Returns the next jx expressions from the issued query. The caller may use jx_lookup_string, jx_lookup_integer and related functions to manipulate the object, and then must call jx_delete when done.

Parameters

q	A query created by catalog_query_create.
stoptime	The absolute time at which to abort.

Returns

A jx expression representing the next result, or null if the end of stream has been reached.

void catalog_query_delete

(

struct catalog_query *

q

)

Delete a completed query object.

Parameters

q	The query to delete.

int catalog_query_send_update	(	const char *	hosts,
		const char *	text
	)

Send update text to the given hosts

hosts is a comma delimited list of hosts, each of which can be host or host:port

Parameters

hosts	A list of hosts to which to send updates
text	String to send

Returns

The number of updates successfully sent,

int catalog_query_send_update_conditional	(	const char *	hosts,
		const char *	text
	)

Send update text to the given hosts, but fail if the update text

cannot be compressed to a suitable size.

Parameters

hosts	A list of hosts to which to send updates
text	String to send

Returns

The number of updates successfully sent,