Changes between Version 2 and Version 3 of RemoteInputFiles

Timestamp:

Feb 4, 2013, 11:53:11 PM (12 years ago)

Author:

davea

Comment:

--

RemoteInputFiles

@@ -1 +1 @@
 = Remote management of input files =
+
+For a file to be used as an input file of a BOINC job,
+it must be available to BOINC clients via HTTP.
+The standard way to do this is put the file
+in the project's "download directory" on the project server.
+
+For projects that use [RemoteJobs remote job submission],
+job submitters don't have login access to the server,
+so they can't store files there directly.
+Instead, BOINC provides two mechanisms that allow
+job submitters to place files on the BOINC server.
+
+Each of these mechanisms deals with two issues:
+
+ * '''File immutability''': BOINC requires that a file
+  of a given name can never be changed.
+  Job submitters can't be expected to obey this rule:
+  they must be able to submit one job with an input file
+  of a given name, and a second job with an input file of
+  the same name but different contents.
+ * File cleanup: There must be some way to clean up
+  files on the server when they are no longer needed.
 
 == Content-based file management ==
 
+This system is used by the [CondorBoinc Condor/BOINC interface].
+If may be useful for other systems as well.
+In this system, the name of a file on the BOINC server
+is based on its MD5 hash; thus file immutability is automatic.
+
+File cleanup is based on file/batch associations.
+Each file can be associated with one or more batches.
+Files that are no longer associated with an active batch are
+automatically deleted from the server.
+
+The system uses two Web RPCs.
+These are implemented as XML sent via HTTP POST;
+the RPC handler is html/user/job_files.php.
+
+The following C++ interfaces are provided
+(in samples/condor/job_rpc.cpp).
+This is to be called on the job submission host;
+the files must exist on that host,
+and their MD5s must have already been computed.
 {{{
 extern int query_files(
@@ -10 +51 @@
     vector<string> &md5s,
     vector<string> &paths,
-    vector<int> &absent_files
+    vector<int> &absent_files           // output
 );
+}}}
 
+Inputs:
+ * '''project_url''': the project's master URL
+ * '''authenticator''': the job submitter's authenticator
+ * '''paths''': a list of file paths on the calling host.
+ * '''md5s''': a list of the MD5s of the files.
+ * '''batch_id''': the ID of a batch whose jobs will reference the files
+  (these jobs need not exist yet).
+
+Action: for each file, see if it exists on the server.
+If it does, create an association to the given batch.
+
+Output:
+ * return value: nonzero on error
+ * '''absent_files''': a list of files not present on the server
+  (represented as indices into the file vector).
+
+{{{
 extern int upload_files (
     const char* project_url,
     const char* authenticator,
-    int batch_id,
+    vector<string> &paths,
     vector<string> &md5s,
-    vector<string> &paths
+    int batch_id
 );
 }}}
 
+Inputs:
+ * '''project_url, authenticator, batch_id''': as above.
+ * '''paths''': a list of paths of files to be uploaded
+ * '''md5s''': a list of MD5 hashes of these files
+ * '''batch_id''': the ID of a batch with which the files are associated
+
+Action: Upload the files, and create associations to the given batch.
+
+Output:
+ * return value: nonzero on error
+
+If you use this system, periodically run the script
+'''html/ops/delete_job_files'''.
+This will delete files that are no longer associated
+with an active batch.
+
 == Per-user file sandbox ==
+