| 1 | RFC - LTTng address API proposal |
| 2 | |
| 3 | Author: David Goulet <david.goulet@efficios.com> |
| 4 | |
| 5 | Contributors: |
| 6 | * Mathieu Desnoyers <mathieu.desnoyers@efficios.com> |
| 7 | * Yannick Brosseau <yannick.brosseau@polymtl.ca> |
| 8 | |
| 9 | Version: |
| 10 | - v0.1: 31/07/2012 |
| 11 | * Initial proposal |
| 12 | |
| 13 | Introduction |
| 14 | ----------------- |
| 15 | |
| 16 | This document proposes the use of string URLs to the command line interface and |
| 17 | API which will deprecate a function and propose new ones. |
| 18 | |
| 19 | The purpose of this proposal is to support network streaming using URL string |
| 20 | format that you can find in proposal doc/proposals/0003-network.consumer.txt, |
| 21 | remove the lttng_uri structure from the API and integrate the URL string to the |
| 22 | API. |
| 23 | |
| 24 | API |
| 25 | ----------------- |
| 26 | |
| 27 | In order not to expose the new lttng_uri structure used to identify trace |
| 28 | location for lttng consumer, the public API will only use string address where |
| 29 | it will be converted in a lttng_uri and sent to the session daemon. |
| 30 | |
| 31 | [*] Create session: |
| 32 | |
| 33 | With the introduction of the enable-consumer command used for network streaming, |
| 34 | the create session command has been modified so the user could define a consumer |
| 35 | location either on the network or local with the command. This change deprecates |
| 36 | the old API function and adds a new one. |
| 37 | |
| 38 | Deprecated: |
| 39 | --> lttng_create_session(const char *name, const char *path); |
| 40 | |
| 41 | Proposed: |
| 42 | --> lttng_create_session_addr(const char *name, const char *addr, |
| 43 | int enable_consumer); |
| 44 | |
| 45 | The _name_ argument is the session name and _addr_ is a string representing the |
| 46 | URL specified by the user which looks like this: |
| 47 | |
| 48 | PROTO://[HOST|IP][:PORT][/PATH] |
| 49 | |
| 50 | Examples: |
| 51 | |
| 52 | * net://myhostname |
| 53 | * net://myhostname:9888 |
| 54 | * net://myhostname/foo/bar |
| 55 | * net://X.X.X.X:9888/foo/bar |
| 56 | |
| 57 | The enable_consumer option will disable the use of the consumer for the tracing |
| 58 | session. This will be useful with the to come snapshot feature. The motivation |
| 59 | behing this flag is to offer the same options as the enable-consumer command |
| 60 | where you can only set the URI for the consumer and not enable it. |
| 61 | |
| 62 | [*] Consumer: |
| 63 | |
| 64 | The current lttng_set_consumer_uri(...) call will be changed to: |
| 65 | |
| 66 | lttng_set_consumer_addr(struct lttng_handle *handle, |
| 67 | const char *addr); |
| 68 | |
| 69 | For both functions (consumer and create), the addr will be translate to a |
| 70 | lttng_uri in the liblttng-ctl and sent to the session daemon. |
| 71 | |
| 72 | With all this, the lttng_uri data structure will not be exposed to the public |
| 73 | API and the user command line interface. |