| Overview |  |
Behaviours: gen_server.
Erlang API for the Machi client-implemented Chain Replication (CORFU-style) protocol.
See also the docs for machi_flu1_client for additional
details on data types and operation descriptions.
The API here is much simpler than the machi_flu1_client or
machi_proxy_flu1_client APIs. This module's API is a
proposed simple-but-complete form for clients who are not
interested in being an active participant in a Machi cluster and to
have the responsibility for Machi internals, i.e., client-side
Chain Replication, client-side read repair, client-side tracking of
internal Machi epoch & projection changes, etc.
This client is implemented as a long-lived Erlang process using
gen_server-style OTP code practice. A naive client can expect
that this process will manage all transient TCP session
disconnections and Machi chain reconfigurations. This client's
efforts are best-effort and can require some time to retry
operations in certain failure cases, i.e., up to several seconds
during a Machi projection & epoch change when a new server is
added to the chain.
Doc TODO: Once this API stabilizes, add all relevant data type details to the EDoc here.
So far, there is one missing client API feature that ought to be added to Machi in the near future: more flexible checksum management.
Add a source annotation to all checksums to indicate where the
checksum was calculated. For example,
Client-side checksums would be the "strongest" type of checksum, meaning that any data corruption (of the original data and/or of the checksum itself) can be detected after the client-side calculation. There are too many horror stories on The Net about IP PDUs that are corrupted but unnoticed due to weak TCP checksums, buggy hardware, buggy OS drivers, etc. Checksum versioning is also desirable if/when the current checksum implementation changes from SHA-1 to something else.
The major operation processing is implemented in a state machine-like
manner. Before attempting an operation X, there's an initial
operation pre-X that takes care of updating the epoch id,
restarting client protocol proxies, and if there's any server
instability (e.g. some server is wedged), then insert some sleep
time. When the chain appears to have stabilized, then we try the X
operation again.
Function name for the pre-X stuff is usually X(), and the
function name for the X stuff is usually X2(). (I.e., the X
stuff follows after pre-X and therefore has a 2 suffix on the
function name.)
pre-X function is named read_repair3(),
and the X function is named read_repair4().
| append_chunk/3 | Append a chunk (binary- or iolist-style) of data to a file
with Prefix. |
| append_chunk/4 | Append a chunk (binary- or iolist-style) of data to a file
with Prefix. |
| append_chunk_extra/4 | Append a chunk (binary- or iolist-style) of data to a file
with Prefix. |
| append_chunk_extra/5 | Append a chunk (binary- or iolist-style) of data to a file
with Prefix. |
| checksum_list/2 | Fetch the list of chunk checksums for File. |
| checksum_list/3 | Fetch the list of chunk checksums for File. |
| code_change/3 | |
| handle_call/3 | |
| handle_cast/2 | |
| handle_info/2 | |
| init/1 | |
| list_files/1 | Fetch the list of all files on the remote FLU. |
| list_files/2 | Fetch the list of all files on the remote FLU. |
| quit/1 | Quit & close the connection to remote FLU and stop our proxy process. |
| read_chunk/4 | Read a chunk of data of size Size from File at Offset. |
| read_chunk/5 | Read a chunk of data of size Size from File at Offset. |
| start_link/1 | Start a local, long-lived process that will be our steady & reliable communication proxy with the fickle & flaky remote Machi server. |
| terminate/2 |
append_chunk(PidSpec, Prefix, Chunk) -> any()
Append a chunk (binary- or iolist-style) of data to a file
with Prefix.
append_chunk(PidSpec, Prefix, Chunk, Timeout) -> any()
Append a chunk (binary- or iolist-style) of data to a file
with Prefix.
append_chunk_extra(PidSpec, Prefix, Chunk, ChunkExtra) -> any()
Append a chunk (binary- or iolist-style) of data to a file
with Prefix.
append_chunk_extra(PidSpec, Prefix, Chunk, ChunkExtra, Timeout) -> any()
Append a chunk (binary- or iolist-style) of data to a file
with Prefix.
checksum_list(PidSpec, File) -> any()
Fetch the list of chunk checksums for File.
checksum_list(PidSpec, File, Timeout) -> any()
Fetch the list of chunk checksums for File.
code_change(OldVsn, S, Extra) -> any()
handle_call(Request, From, S) -> any()
handle_cast(Msg, S) -> any()
handle_info(Info, S) -> any()
init(X1) -> any()
list_files(PidSpec) -> any()
Fetch the list of all files on the remote FLU.
list_files(PidSpec, Timeout) -> any()
Fetch the list of all files on the remote FLU.
quit(PidSpec) -> any()
Quit & close the connection to remote FLU and stop our proxy process.
read_chunk(PidSpec, File, Offset, Size) -> any()
Read a chunk of data of size Size from File at Offset.
read_chunk(PidSpec, File, Offset, Size, Timeout) -> any()
Read a chunk of data of size Size from File at Offset.
start_link(P_srvr_list) -> any()
Start a local, long-lived process that will be our steady & reliable communication proxy with the fickle & flaky remote Machi server.
terminate(Reason, State) -> any()
Generated by EDoc, May 20 2015, 12:36:35.