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[Xen-devel] [PATCH] some API spec improvements

From: John Levon <levon@xxxxxxxxxxxxxxxxx>

Date: Tue, 24 Apr 2007 14:45:50 +0100

Delivery-date: Tue, 24 Apr 2007 06:40:14 -0700

List-id: Xen developer discussion <xen-devel.lists.xensource.com>

# HG changeset patch # User john.levon@xxxxxxx # Date 1177421676 -3600 # Node ID 84cf09a18710022e5ff9f2eb43e065e6e23bc643 # Parent 9e44519ee9a25121003357c4e3e825d64c3b13a4 Xen API specification improvements. Move the error list to be more prominent, and explicitly document which generic error codes can be returned by all methods. Mark host CPU flags/features return value as unspecified. Document PERMISSION_DENIED. Document error returns of session.login_with_password. Signed-off-by: John Levon <john.levon@xxxxxxx> diff -r 9e44519ee9a2 -r 84cf09a18710 docs/xen-api/xenapi-datamodel.tex --- a/docs/xen-api/xenapi-datamodel.tex Sat Apr 21 11:37:34 2007 +0100 +++ b/docs/xen-api/xenapi-datamodel.tex Tue Apr 24 14:34:36 2007 +0100 @@ -225,6 +225,249 @@ The following enumeration types are used \end{longtable} \vspace{1cm} +\newpage +\section{Error Handling} +When a low-level transport error occurs, or a request is malformed at the HTTP +or XML-RPC level, the server may send an XML-RPC Fault response, or the client +may simulate the same. The client must be prepared to handle these errors, +though they may be treated as fatal. On the wire, these are transmitted in a +form similar to this: + +\begin{verbatim} + <methodResponse> + <fault> + <value> + <struct> + <member> + <name>faultCode</name> + <value><int>-1</int></value> + </member> + <member> + <name>faultString</name> + <value><string>Malformed request</string></value> + </member> + </struct> + </value> + </fault> + </methodResponse> +\end{verbatim} + +All other failures are reported with a more structured error response, to +allow better automatic response to failures, proper internationalisation of +any error message, and easier debugging. On the wire, these are transmitted +like this: + +\begin{verbatim} + <struct> + <member> + <name>Status</name> + <value>Failure</value> + </member> + <member> + <name>ErrorDescription</name> + <value> + <array> + <data> + <value>MAP_DUPLICATE_KEY</value> + <value>Customer</value> + <value>eSpeil Inc.</value> + <value>eSpeil Incorporated</value> + </data> + </array> + </value> + </member> + </struct> +\end{verbatim} + +Note that {\tt ErrorDescription} value is an array of string values. The +first element of the array is an error code; the remainder of the array are +strings representing error parameters relating to that code. In this case, +the client has attempted to add the mapping {\tt Customer $\rightarrow$ +eSpiel Incorporated} to a Map, but it already contains the mapping +{\tt Customer $\rightarrow$ eSpiel Inc.}, and so the request has failed. + +The reference below lists each possible error returned by each method. +As well as the errors explicitly listed, any method may return low-level +errors as described above, or any of the following generic errors: + +\begin{itemize} +\item HANDLE\_INVALID +\item INTERNAL\_ERROR +\item MAP\_DUPLICATE\_KEY +\item MESSAGE\_METHOD\_UNKNOWN +\item MESSAGE\_PARAMETER\_COUNT\_MISMATCH +\item OPERATION\_NOT\_ALLOWED +\item PERMISSION\_DENIED +\item SESSION\_INVALID +\end{itemize} + +Each possible error code is documented in the following section. + +\subsection{Error Codes} + +\subsubsection{HANDLE\_INVALID} + +You gave an invalid handle. The object may have recently been deleted. +The class parameter gives the type of reference given, and the handle +parameter echoes the bad value given. + +\vspace{0.3cm} +{\bf Signature:} +\begin{verbatim}HANDLE_INVALID(class, handle)\end{verbatim} +\begin{center}\rule{10em}{0.1pt}\end{center} + +\subsubsection{INTERNAL\_ERROR} + +The server failed to handle your request, due to an internal error. The +given message may give details useful for debugging the problem. + +\vspace{0.3cm} +{\bf Signature:} +\begin{verbatim}INTERNAL_ERROR(message)\end{verbatim} +\begin{center}\rule{10em}{0.1pt}\end{center} + +\subsubsection{MAP\_DUPLICATE\_KEY} + +You tried to add a key-value pair to a map, but that key is already there. +The key, current value, and the new value that you tried to set are all +echoed. + +\vspace{0.3cm} +{\bf Signature:} +\begin{verbatim}MAP_DUPLICATE_KEY(key, current value, new value)\end{verbatim} +\begin{center}\rule{10em}{0.1pt}\end{center} + +\subsubsection{MESSAGE\_METHOD\_UNKNOWN} + +You tried to call a method that does not exist. The method name that you +used is echoed. + +\vspace{0.3cm} +{\bf Signature:} +\begin{verbatim}MESSAGE_METHOD_UNKNOWN(method)\end{verbatim} +\begin{center}\rule{10em}{0.1pt}\end{center} + +\subsubsection{MESSAGE\_PARAMETER\_COUNT\_MISMATCH} + +You tried to call a method with the incorrect number of parameters. The +fully-qualified method name that you used, and the number of received and +expected parameters are returned. + +\vspace{0.3cm} +{\bf Signature:} +\begin{verbatim}MESSAGE_PARAMETER_COUNT_MISMATCH(method, expected, received)\end{verbatim} +\begin{center}\rule{10em}{0.1pt}\end{center} + +\subsubsection{NETWORK\_ALREADY\_CONNECTED} + +You tried to create a PIF, but the network you tried to attach it to is +already attached to some other PIF, and so the creation failed. + +\vspace{0.3cm} +{\bf Signature:} +\begin{verbatim}NETWORK_ALREADY_CONNECTED(network, connected PIF)\end{verbatim} +\begin{center}\rule{10em}{0.1pt}\end{center} + +\subsubsection{OPERATION\_NOT\_ALLOWED} + +You attempted an operation that was not allowed. + +\vspace{0.3cm} +No parameters. +\begin{center}\rule{10em}{0.1pt}\end{center} + +\subsubsection{PERMISSION\_DENIED} + +You do not have the required permissions to perform the operation. + +\vspace{0.3cm} +No parameters. +\begin{center}\rule{10em}{0.1pt}\end{center} + +\subsubsection{PIF\_IS\_PHYSICAL} + +You tried to destroy a PIF, but it represents an aspect of the physical +host configuration, and so cannot be destroyed. The parameter echoes the +PIF handle you gave. + +\vspace{0.3cm} +{\bf Signature:} +\begin{verbatim}PIF_IS_PHYSICAL(PIF)\end{verbatim} +\begin{center}\rule{10em}{0.1pt}\end{center} + +\subsubsection{SESSION\_AUTHENTICATION\_FAILED} + +The credentials given by the user are incorrect, so access has been denied, +and you have not been issued a session handle. + +\vspace{0.3cm} +No parameters. +\begin{center}\rule{10em}{0.1pt}\end{center} + +\subsubsection{SESSION\_INVALID} + +You gave an invalid session handle. It may have been invalidated by a +server restart, or timed out. You should get a new session handle, using +one of the session.login\_ calls. This error does not invalidate the +current connection. The handle parameter echoes the bad value given. + +\vspace{0.3cm} +{\bf Signature:} +\begin{verbatim}SESSION_INVALID(handle)\end{verbatim} +\begin{center}\rule{10em}{0.1pt}\end{center} + +\subsubsection{SESSION\_NOT\_REGISTERED} + +This session is not registered to receive events. You must call +event.register before event.next. The session handle you are using is +echoed. + +\vspace{0.3cm} +{\bf Signature:} +\begin{verbatim}SESSION_NOT_REGISTERED(handle)\end{verbatim} +\begin{center}\rule{10em}{0.1pt}\end{center} + +\subsubsection{VALUE\_NOT\_SUPPORTED} + +You attempted to set a value that is not supported by this implementation. +The fully-qualified field name and the value that you tried to set are +returned. Also returned is a developer-only diagnostic reason. + +\vspace{0.3cm} +{\bf Signature:} +\begin{verbatim}VALUE_NOT_SUPPORTED(field, value, reason)\end{verbatim} +\begin{center}\rule{10em}{0.1pt}\end{center} + +\subsubsection{VLAN\_TAG\_INVALID} + +You tried to create a VLAN, but the tag you gave was invalid -- it mmust be +between 0 and 4095. The parameter echoes the VLAN tag you gave. + +\vspace{0.3cm} +{\bf Signature:} +\begin{verbatim}VLAN_TAG_INVALID(VLAN)\end{verbatim} +\begin{center}\rule{10em}{0.1pt}\end{center} + +\subsubsection{VM\_BAD\_POWER\_STATE} + +You attempted an operation on a VM that was not in an appropriate power +state at the time; for example, you attempted to start a VM that was +already running. The parameters returned are the VM's handle, and the +expected and actual VM state at the time of the call. + +\vspace{0.3cm} +{\bf Signature:} +\begin{verbatim}VM_BAD_POWER_STATE(vm, expected, actual)\end{verbatim} +\begin{center}\rule{10em}{0.1pt}\end{center} + +\subsubsection{VM\_HVM\_REQUIRED} + +HVM is required for this operation + +\vspace{0.3cm} +{\bf Signature:} +\begin{verbatim}VM_HVM_REQUIRED(vm)\end{verbatim} +\begin{center}\rule{10em}{0.1pt}\end{center} \newpage \section{Class: session} @@ -275,6 +518,11 @@ session ref ID of newly created session + +\vspace{0.3cm} + +\noindent{\bf Possible Error Codes:} {\tt SESSION\_AUTHENTICATION\_FAILED} + \vspace{0.3cm} \vspace{0.3cm} \vspace{0.3cm} @@ -7100,7 +7348,9 @@ value of the field \subsubsection{RPC name:~get\_flags} {\bf Overview:} -Get the flags field of the given host\_cpu. +Get the flags field of the given host\_cpu. As of this version of the +API, the semantics of the returned string are explicitly unspecified, +and may change in the future. \noindent {\bf Signature:} \begin{verbatim} string get_flags (session_id s, host_cpu ref self)\end{verbatim} @@ -7132,7 +7382,9 @@ value of the field \subsubsection{RPC name:~get\_features} {\bf Overview:} -Get the features field of the given host\_cpu. +Get the features field of the given host\_cpu. As of this version of the +API, the semantics of the returned string are explicitly unspecified, +and may change in the future. \noindent {\bf Signature:} \begin{verbatim} string get_features (session_id s, host_cpu ref self)\end{verbatim} @@ -14192,224 +14444,3 @@ all fields from the object \vspace{0.3cm} \vspace{0.3cm} -\vspace{1cm} -\newpage -\section{Error Handling} -When a low-level transport error occurs, or a request is malformed at the HTTP -or XML-RPC level, the server may send an XML-RPC Fault response, or the client -may simulate the same. The client must be prepared to handle these errors, -though they may be treated as fatal. On the wire, these are transmitted in a -form similar to this: - -\begin{verbatim} - <methodResponse> - <fault> - <value> - <struct> - <member> - <name>faultCode</name> - <value><int>-1</int></value> - </member> - <member> - <name>faultString</name> - <value><string>Malformed request</string></value> - </member> - </struct> - </value> - </fault> - </methodResponse> -\end{verbatim} - -All other failures are reported with a more structured error response, to -allow better automatic response to failures, proper internationalisation of -any error message, and easier debugging. On the wire, these are transmitted -like this: - -\begin{verbatim} - <struct> - <member> - <name>Status</name> - <value>Failure</value> - </member> - <member> - <name>ErrorDescription</name> - <value> - <array> - <data> - <value>MAP_DUPLICATE_KEY</value> - <value>Customer</value> - <value>eSpeil Inc.</value> - <value>eSpeil Incorporated</value> - </data> - </array> - </value> - </member> - </struct> -\end{verbatim} - -Note that {\tt ErrorDescription} value is an array of string values. The -first element of the array is an error code; the remainder of the array are -strings representing error parameters relating to that code. In this case, -the client has attempted to add the mapping {\tt Customer $\rightarrow$ -eSpiel Incorporated} to a Map, but it already contains the mapping -{\tt Customer $\rightarrow$ eSpiel Inc.}, and so the request has failed. - -Each possible error code is documented in the following section. - -\subsection{Error Codes} - -\subsubsection{HANDLE\_INVALID} - -You gave an invalid handle. The object may have recently been deleted. -The class parameter gives the type of reference given, and the handle -parameter echoes the bad value given. - -\vspace{0.3cm} -{\bf Signature:} -\begin{verbatim}HANDLE_INVALID(class, handle)\end{verbatim} -\begin{center}\rule{10em}{0.1pt}\end{center} - -\subsubsection{INTERNAL\_ERROR} - -The server failed to handle your request, due to an internal error. The -given message may give details useful for debugging the problem. - -\vspace{0.3cm} -{\bf Signature:} -\begin{verbatim}INTERNAL_ERROR(message)\end{verbatim} -\begin{center}\rule{10em}{0.1pt}\end{center} - -\subsubsection{MAP\_DUPLICATE\_KEY} - -You tried to add a key-value pair to a map, but that key is already there. -The key, current value, and the new value that you tried to set are all -echoed. - -\vspace{0.3cm} -{\bf Signature:} -\begin{verbatim}MAP_DUPLICATE_KEY(key, current value, new value)\end{verbatim} -\begin{center}\rule{10em}{0.1pt}\end{center} - -\subsubsection{MESSAGE\_METHOD\_UNKNOWN} - -You tried to call a method that does not exist. The method name that you -used is echoed. - -\vspace{0.3cm} -{\bf Signature:} -\begin{verbatim}MESSAGE_METHOD_UNKNOWN(method)\end{verbatim} -\begin{center}\rule{10em}{0.1pt}\end{center} - -\subsubsection{MESSAGE\_PARAMETER\_COUNT\_MISMATCH} - -You tried to call a method with the incorrect number of parameters. The -fully-qualified method name that you used, and the number of received and -expected parameters are returned. - -\vspace{0.3cm} -{\bf Signature:} -\begin{verbatim}MESSAGE_PARAMETER_COUNT_MISMATCH(method, expected, received)\end{verbatim} -\begin{center}\rule{10em}{0.1pt}\end{center} - -\subsubsection{NETWORK\_ALREADY\_CONNECTED} - -You tried to create a PIF, but the network you tried to attach it to is -already attached to some other PIF, and so the creation failed. - -\vspace{0.3cm} -{\bf Signature:} -\begin{verbatim}NETWORK_ALREADY_CONNECTED(network, connected PIF)\end{verbatim} -\begin{center}\rule{10em}{0.1pt}\end{center} - -\subsubsection{OPERATION\_NOT\_ALLOWED} - -You attempted an operation that was not allowed. - -\vspace{0.3cm} -No parameters. -\begin{center}\rule{10em}{0.1pt}\end{center} - -\subsubsection{PIF\_IS\_PHYSICAL} - -You tried to destroy a PIF, but it represents an aspect of the physical -host configuration, and so cannot be destroyed. The parameter echoes the -PIF handle you gave. - -\vspace{0.3cm} -{\bf Signature:} -\begin{verbatim}PIF_IS_PHYSICAL(PIF)\end{verbatim} -\begin{center}\rule{10em}{0.1pt}\end{center} - -\subsubsection{SESSION\_AUTHENTICATION\_FAILED} - -The credentials given by the user are incorrect, so access has been denied, -and you have not been issued a session handle. - -\vspace{0.3cm} -No parameters. -\begin{center}\rule{10em}{0.1pt}\end{center} - -\subsubsection{SESSION\_INVALID} - -You gave an invalid session handle. It may have been invalidated by a -server restart, or timed out. You should get a new session handle, using -one of the session.login\_ calls. This error does not invalidate the -current connection. The handle parameter echoes the bad value given. - -\vspace{0.3cm} -{\bf Signature:} -\begin{verbatim}SESSION_INVALID(handle)\end{verbatim} -\begin{center}\rule{10em}{0.1pt}\end{center} - -\subsubsection{SESSION\_NOT\_REGISTERED} - -This session is not registered to receive events. You must call -event.register before event.next. The session handle you are using is -echoed. - -\vspace{0.3cm} -{\bf Signature:} -\begin{verbatim}SESSION_NOT_REGISTERED(handle)\end{verbatim} -\begin{center}\rule{10em}{0.1pt}\end{center} - -\subsubsection{VALUE\_NOT\_SUPPORTED} - -You attempted to set a value that is not supported by this implementation. -The fully-qualified field name and the value that you tried to set are -returned. Also returned is a developer-only diagnostic reason. - -\vspace{0.3cm} -{\bf Signature:} -\begin{verbatim}VALUE_NOT_SUPPORTED(field, value, reason)\end{verbatim} -\begin{center}\rule{10em}{0.1pt}\end{center} - -\subsubsection{VLAN\_TAG\_INVALID} - -You tried to create a VLAN, but the tag you gave was invalid -- it mmust be -between 0 and 4095. The parameter echoes the VLAN tag you gave. - -\vspace{0.3cm} -{\bf Signature:} -\begin{verbatim}VLAN_TAG_INVALID(VLAN)\end{verbatim} -\begin{center}\rule{10em}{0.1pt}\end{center} - -\subsubsection{VM\_BAD\_POWER\_STATE} - -You attempted an operation on a VM that was not in an appropriate power -state at the time; for example, you attempted to start a VM that was -already running. The parameters returned are the VM's handle, and the -expected and actual VM state at the time of the call. - -\vspace{0.3cm} -{\bf Signature:} -\begin{verbatim}VM_BAD_POWER_STATE(vm, expected, actual)\end{verbatim} -\begin{center}\rule{10em}{0.1pt}\end{center} - -\subsubsection{VM\_HVM\_REQUIRED} - -HVM is required for this operation - -\vspace{0.3cm} -{\bf Signature:} -\begin{verbatim}VM_HVM_REQUIRED(vm)\end{verbatim} -\begin{center}\rule{10em}{0.1pt}\end{center} _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxxxxxxxx http://lists.xensource.com/xen-devel

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