Processes

Type of Processes

Weaver supports multiple type of processes, as listed below. Each one of them are accessible through the same API interface, but they have different implications.

See also

Section Examples provides multiple concrete use cases of Deploy and Execute request payloads for diverse set of applications.

Builtin

These processes come pre-packaged with Weaver. They will be available directly on startup of the application and re-updated on each boot to make sure internal database references are updated with any source code changes.

Theses processes typically correspond to utility operations. They are specifically useful when employed as step within a Workflow process that requires data-type conversion between input/output of similar, but not perfectly, compatible definitions.

For example, process weaver.processes.builtin.jsonarray2netcdf takes a single input JSON file which its content contains an array-list of NetCDF file references, and returns them directly as the corresponding list of output files. These two different file formats (single JSON to multiple NetCDF) can then be used to map two processes with these respective output and inputs.

As of the latest release, following builtin processes are available:

All builtin processes are marked with weaver.processes.constants.CWL_REQUIREMENT_APP_BUILTIN in the CWL hints section and are all defined in weaver.processes.builtin.

WPS-1/2

This kind of process corresponds to a traditional WPS XML or JSON endpoint (depending of supported version) prior to WPS-REST specification. When the WPS-REST process is deployed in Weaver using an URL reference to an WPS-1/2 process, Weaver parses and converts the XML or JSON body of the response and registers the process locally using this definition. This allows a remote server offering limited functionalities (e.g.: no REST bindings supported) to provide them through Weaver.

A minimal Deploy request body for this kind of process could be as follows:

{
  "processDescription": {
    "process": {
      "id": "my-process-reference"
    }
  },
  "executionUnit": [
    {
      "href": "https://example.com/wps?service=WPS&request=DescribeProcess&identifier=my-process&version=1.0.0"
    }
  ]
}

This would tell Weaver to locally deploy the my-process-reference process using the WPS-1 URL reference that is expected to return a DescribeProcess XML schema. Provided that this endpoint can be resolved and parsed according to typical WPS specification, this should result into a successful process registration. The deployed process would then be accessible with DescribeProcess requests.

The above deployment procedure can be automated on startup using Weaver’s wps_processes.yml configuration file. Please refer to Configuration of WPS Processes section for more details on this matter.

Warning

Because Weaver creates a snapshot of the reference process at the moment it was deployed, the local process definition could become out-of-sync with the remote reference where the Execute request will be sent. Refer to Remote Provider section for more details to work around this issue.

See also

WPS-REST

This process type is the main component of Weaver. All other process types are converted to this one either through some parsing (e.g.: WPS-1/2) or with some requirement indicators (e.g.: Builtin, Workflow) for special handling.

When deploying one such process directly, it is expected to have a reference to a CWL Application Package. This is most of the time employed to wrap a reference docker image process. The reference package can be provided in multiple ways as presented below.

Note

When a process is deployed with any of the below supported Application Package formats, additional parsing of this CWL as well as complementary details directly within the WPS deployment body is accomplished. See Correspondence between CWL and WPS fields section for more details.

Package as Literal Execution Unit Block

In this situation, the CWL definition is provided as is using JSON-formatted package embedded within the POST {WEAVER_URL}/processes (Deploy) request. The request payload would take the following shape:

{
  "processDescription": {
    "process": {
      "id": "my-process-reference"
    }
  },
  "executionUnit": [
    {
      "unit": {
        "cwlVersion": "v1.0",
        "class": "CommandLineTool",
        "inputs": ["<...>"],
        "outputs": ["<...>"],
        "<...>": "<...>"
      }
    }
  ]
}

ESGF-CWT

For traditional WPS-1 process type, Weaver adds default values to CWL definition. As we can see in weaver/processes/wps_package.py, the following default values for the CWL package are:

cwl_package = OrderedDict([
    ("cwlVersion", "v1.0"),
    ("class", "CommandLineTool"),
    ("hints", {
        CWL_REQUIREMENT_APP_WPS1: {
            "provider": get_url_without_query(wps_service_url),
            "process": process_id,
        }}),
])

In ESGF-CWT processes, ESGF-CWTRequirement hint must be used instead of usual WPS1Requirement, contained in the weaver.processes.constants.CWL_REQUIREMENT_APP_WPS1 variable. The handling of this technicality is handled in weaver/processes/wps_package.py. We can define ESGF-CWT processes using this syntax:

{
  "cwlVersion": "v1.0",
  "class": "CommandLineTool",
  "hints": {
    "ESGF-CWTRequirement": {
      "provider": "https://edas.nccs.nasa.gov/wps/cwt",
      "process": "xarray.subset"
    }
  }
}

Workflow

Processes categorized as Workflow are very similar to WPS-REST processes. From the API standpoint, they actually look exactly the same as an atomic process when calling DescribeProcess or Execute requests. The difference lies within the referenced Application Package which uses a CWL Workflow instead of typical CWL CommandLineTool, and therefore, modifies how the process is internally executed.

For Workflow processes to be deploy-able and executable, it is mandatory that Weaver is configured as EMS or HYBRID (see: Configuration Settings). This requirement is due to the nature of workflows that chain processes that need to be dispatched to known remote ADES servers (see: Configuration of Data Sources and Workflow Operations).

Given that a Workflow process was successfully deployed and that all process steps can be resolved, calling its Execute request will tell Weaver to parse the chain of operations and send step process execution requests to relevant ADES picked according to data sources. Each step’s job will then gradually be monitored from the remote ADES until completion, and upon successful result, the EMS will retrieve the data references to pass it down to the following step. When the complete chain succeeds, the final results of the last step will be provided as Workflow output as for atomic processes. In case of failure, the error will be indicated in the log with the appropriate step and message where the error occurred.

Note

Although chaining sub-workflow(s) within a bigger scoped workflow is technically possible, this have not yet been fully explored (tested) in Weaver. There is a chance that Data-Source resolution fails to identify where to dispatch the step in this situation. If this impacts you, please vote and indicate your concern on issue #171.

Remote Provider

Remote provider correspond to a remote service that provides similar interfaces as supported by Weaver (WPS-like). For example, a remote WPS-1 XML endpoint can be referenced as a provider. When an API Providers-scoped request is executed, for example to list is processes capabilities (see GetCapabilities), Weaver will send the corresponding request using the registered reference URL to access the remote server and reply with parsed response, as if they its processes were registered locally.

Since remote providers obviously require access to the remote service, Weaver will only be able to provide results if the service is accessible with respect to standard implementation features and supported specifications.

The main advantage of using Weaver’s endpoint rather than directly accessing the referenced remote provider processes is in the case of limited functionality offered by the service. For instance, WPS-1 do not always offer GetStatus feature, and there is no extensive job monitoring availability. Since Weaver wraps the original reference with its own endpoints, these features indirectly become employable. Similarly, although WPS-1 offer XML-only endpoints, the parsing operation accomplished by Weaver makes theses services available as WPS-REST JSON endpoints. On top of that, registering remote providers into Weaver allows the user to use it as a central hub to keep references to all his accessible services and dispatch jobs from a common location.

A remote provider differs from previously presented WPS-1/2 processes such that the underlying processes of the service are not registered locally. For example, if a remote service has two WPS processes, only top-level service URL will be registered locally (in Weaver’s database) and the application will have no explicit knowledge of these remote processes. When calling process-specific requests (e.g.: DescribeProcess or Execute), Weaver will re-send the corresponding request directly to the remote provider each time and return the result accordingly. On the other hand, a WPS-1/2 reference would be parsed and saved locally with the response at the time of deployment. This means that a deployed WPS-1/2 reference would act as a snapshot of the reference (which could become out-of-sync), while Remote Provider will dynamically update according to the re-fetched response from the remote service. If our example remote service was extended to have a third WPS process, it would immediately be reflected in GetCapabilities and DescribeProcess retrieved via Weaver Providers-scoped requests. This would not be the case for the WPS-1/2 reference that would need manual update (deploy the third process to register it in Weaver).

An example body of the register provider request could be as follows:

{
  "id": "my-service",
  "url": "https://example.com/wps",
  "public": true
}

Then, processes of this registered Remote Provider will be accessible. For example, if the referenced service by the above URL add a WPS process identified by my-process, its JSON description would be obtained with following request (DescribeProviderProcess):

GET {WEAVER_URL}/providers/my-service/processes/my-process

Note

Process my-process in the example is not registered locally. From the point of view of Weaver’s processes (i.e.: route /processes/{id}), it does NOT exist. You must absolutely use the provider-prefixed route /providers/{id}/processes/{id} to explicitly fetch and resolve this remote process definition.

Warning

API requests scoped under Providers are Weaver-specific implementation. These are not part of OGC API - Processes specification.

Managing processes included in Weaver ADES/EMS

Following steps represent the typical steps applied to deploy a process, execute it and retrieve the results.

Register a new process (Deploy)

Deployment of a new process is accomplished through the POST {WEAVER_URL}/processes POST {WEAVER_URL}/processes (Deploy) request.

The request body requires mainly two components:

  • processDescription:
    Defines the process identifier, metadata, inputs, outputs, and some execution specifications. This mostly corresponds to information that corresponds to a traditional WPS definition.
  • executionUnit:
    Defines the core details of the Application Package. This corresponds to the explicit CWL definition that indicates how to execute the given application.

Upon deploy request, Weaver will either respond with a successful result, or with the appropriate error message, whether caused by conflicting ID, invalid definitions or other parsing issues. A successful process deployment will result in this process to become available for following steps.

Warning

When a process is deployed, it is not necessarily available immediately. This is because process visibility also needs to be updated. The process must be made public to allow its discovery. For updating visibility, please refer to the PUT {WEAVER_URL}/processes/{id}/visibility (Visibility) request.

After deployment and visibility preconditions have been met, the corresponding process should become available through DescribeProcess requests and other routes that depend on an existing process.

Note that when a process is deployed using the WPS-REST interface, it also becomes available through the WPS-1/2 interface with the same identifier and definition. Because of compatibility limitations, some parameters in the WPS-1/2 might not be perfectly mapped to the equivalent or adjusted WPS-REST interface, although this concerns mostly only new features such as status monitoring. For most traditional use cases, properties are mapped between the two interfaces, but it is recommended to use the WPS-REST one because of the added features.

Access registered process(es) (GetCapabilities, DescribeProcess)

Available processes can all be listed using GET {WEAVER_URL}/processes (GetCapabilities) request. This request will return all locally registered process summaries. Other return formats and filters are also available according to provided request query parameters. Note that processes not marked with public visibility will not be listed in this result.

For more specific process details, the GET {WEAVER_URL}/processes/{id} (DescribeProcess) request should be used. This will return all information that define the process references and expected inputs/outputs.

Note

For remote processes (see: Remote Provider), Provider requests are also available for more fine-grained search of underlying processes. These processes are not necessarily listed as local processes, and will therefore sometime not yield any result if using the typical DescribeProcess endpoint.

All routes listed under Process requests should normally be applicable for remote processes by prefixing them with /providers/{id}.

Execution of a process (Execute)

Process execution (i.e.: submitting a Job) is accomplished using the POST {WEAVER_URL}/processes/{id}/jobs (Execute) request. This section will first describe the basics of this request format, and after go into details for specific use cases and parametrization of various input/output combinations. Let’s employ the following example of JSON body sent to the Job execution to better illustrate the requirements.

{
  "mode": "async",
  "response": "document",
  "inputs": [
    {
      "id": "input-file",
      "href": "<some-file-reference"
    },
    {
      "id": "input-value",
      "data": 1,
    }
  ],
  "outputs": [
    {
      "id": "output",
      "transmissionMode": "reference"
    }
  ]
}

Basic Details

Todo

Support sync mode. Relates to https://github.com/crim-ca/weaver/issues/247.

The first field is mode, it basically tells whether to run the Process in a blocking (sync) or non-blocking (async) manner. Note that support is currently limited for mode sync as this use case is often more cumbersome than async execution. Effectively, sync mode requires to have a task worker executor available to run the Job (otherwise it fails immediately due to lack of processing resource), and the requester must wait for the whole execution to complete to obtain the result. Given that Process could take a very long time to complete, it is not practical to execute them in this manner and potentially have to wait hours to retrieve outputs. Instead, the preferred and default approach is to request an async Job execution. When doing so, Weaver will add this to a task queue for processing, and will immediately return a Job identifier and location where the user can probe for its status, using GetStatus monitoring request. As soon as any task worker becomes available, it will pick any leftover queued Job to execute it.

The second field is response. At the time being, Weaver only supports document value. This parameter is present only for compatibility with other ADES implementation, but does not actually affects Weaver’s response.

Following are the inputs definition. This is the most important section of the request body. It defines which parameters to forward to the referenced Process to be executed. All id elements in this Job request body must correspond to valid inputs from the definition returned by DescribeProcess response. Obviously, all formatting requirements (i.e.: proper file MIME-types), data types (e.g.: int, string, etc.) and validations rules (e.g.: minOccurs, AllowedValues, etc.) must also be fulfilled. When providing files as input, multiple protocols are supported. See later section File Reference Types for details.

Finally, the outputs section defines, for each id corresponding to the Process definition, how to report the produced outputs from a successful Job completion. Again, Weaver only implement the reference result for the time being as this is the most common variation. In this case, the produced file is stored locally and exposed externally with returned reference URL. The other (unimplemented) mode value would return the contents directly in the response instead of the URL.

Note

Other parameters can be added to the request to provide further functionalities. Above fields are the minimum requirements to request a Job. Please refer to the OpenAPI Execute definition for all applicable features.

Note

Since most of the time, returned files are not human readable or are simply too large to be displayed, the transmissionMode: value is rarely employed. Also, it is to be noted that outputs representing LiteralData (which is even more uncommon) would automatically be represented as value without explicitly requesting it, as there would not be any file to return. If this poses problem or you encounter a valid use-case where value would be useful for your needs, please submit a new issue to request the feature.

Execution Steps

Once the Job is submitted, its status should initially switch to accepted. This effectively means that the Job is pending execution (task queued), but is not yet executing. When a worker retrieves it for execution, the status will change to started for preparation steps (i.e.: allocation resources, retrieving required parametrization details, etc.), followed by running when effectively reaching the execution step of the underlying Application Package operation. This status will remain as such until the operation completes, either with succeeded or failed status.

At any moment during async execution, the Job status can be requested using GET {WEAVER_URL}/processes/{id}/jobs/{id} (GetStatus). Note that depending on the timing at which the user executes this request and the availability of task workers, it could be possible that the Job be already in running state, or even failed in case of early problem detected.

When the Job reaches its final state, multiple parameters will be adjusted in the status response to indicate its completion, notably the completed percentage, time it finished execution and full duration. At that moment, the requests for retrieving either error details or produced outputs become accessible. Examples are presented in GetResult section.

Process Operations

Todo

detail ‘operations’ accomplished (stage-in, exec-cwl, stage-out)

Workflow Operations

Todo

same as prev + ‘operations’ (deploy based on data-source, visibility, exec-remote for each step, pull-result)

File Reference Types

Most inputs can be categorized into two of the most commonly employed types, namely LiteralData and ComplexData. The former represents basic values such as integers or strings, while the other represents a file reference. Files in Weaver (and WPS in general) can be specified with any formats as MIME-type.

As for standard WPS, remote file references are usually limited to http(s) scheme, unless the process takes an input string and parses the unusual reference from the literal data to process it by itself. On the other hand, Weaver supports all following reference schemes.

  • http(s)://

  • file://

  • opensearchfile:// [experimental]

  • s3:// [experimental]

The method in which Weaver will handle such references depends on its configuration, in other words, whether it is running as ADES or EMS (see: Configuration), as well as depending on some other CWL package requirements. These use-cases are described below.

Warning

Missing schemes in URL reference are considered identical as if file:// was used. In most cases, if not always, an execution request should not employ this scheme unless the file is ensured to be at the specific location where the running Weaver application can find it. This scheme is usually only employed as byproduct of the fetch operation that Weaver uses to provide the file locally to underlying CWL application package to be executed.

When Weaver is able to figure out that the process needs to be executed locally in ADES mode, it will fetch all necessary files prior to process execution in order to make them available to the CWL package. When Weaver is in EMS configuration, it will always forward remote references (regardless of scheme) exactly as provided as input of the process execution request, since it assumes it needs to dispatch the execution to another ADES remote server, and therefore only needs to verify that the file reference is reachable remotely. In this case, it becomes the responsibility of this remote instance to handle the reference appropriately. This also avoids potential problems such as if Weaver as EMS doesn’t have authorized access to a link that only the target ADES would have access to.

When CWL package defines WPS1Requirement under hints for corresponding WPS-1/2 remote processes being monitored by Weaver, it will skip fetching of http(s)-based references since that would otherwise lead to useless double downloads (one on Weaver and the other on the WPS side). It is the same in case of ESGF-CWTRequirement employed for ESGF-CWT processes. Because these processes do not always support S3 buckets, and because Weaver supports many variants of S3 reference formats, it will first fetch the S3 reference using its internal AWS Configuration, and then expose this downloaded file as https(s) reference accessible by the remote WPS process.

Note

When Weaver is fetching remote files with http(s)://, it can take advantage of additional request options to support unusual or server-specific handling of remote reference as necessary. This could be employed for instance to attribute access permissions only to some given ADES server by providing additional authorization tokens to the requests. Please refer to Configuration of Request Options for this matter.

When using S3 references, Weaver will attempt to retrieve the file using server AWS Configuration and AWS Credentials. Provided that the corresponding S3 bucket can be accessed by the running Weaver application, it will fetch the file and store it locally temporarily for CWL execution.

Note

When using S3 buckets, authorization are handled through typical AWS credentials and role permissions. This means that AWS access must be granted to the application in order to allow it fetching the file. There are also different formats of S3 reference formats handled by Weaver. Please refer to Configuration of AWS S3 Buckets for more details.

When using OpenSearch references, additional parameters are necessary to handle retrieval of specific file URL. Please refer to OpenSearch Data Source for more details.

Following table summarize the default behaviour of input file reference handling of different situations when received as input argument of process execution. For simplification, keyword <any> is used to indicate that any other value in the corresponding column can be substituted for a given row when applied with conditions of other columns, which results to same operational behaviour. Elements that behave similarly are also presented together in rows to reduce displayed combinations.

Configuration

Process Type

File Scheme

Applied Operation

<any>

<any>

opensearchfile://

Query and re-process 1

ADES

file://

Convert to http(s):// 2

http(s)://

Nothing (unmodified)

s3://

Fetch and convert to http(s):// 4

file://

Nothing (file already local)

http(s)://

Fetch and convert to file://

s3://

EMS

file://

Convert to http(s):// 2

http(s)://

Nothing (unmodified, step will handle it)

s3://

HYBRID

Note: HYBRID assumes ADES role (remote processes)

file://

Convert to http(s):// 2

http(s)://

Nothing (unmodified)

s3://

Fetch and convert to http(s):// 4

Note: HYBRID assumes ADES role (local processes)

file://

Nothing (unmodified)

http(s)://

Fetch and convert to file://

Note: HYBRID assumes EMS role

file://

Convert to http(s):// 2

http(s)://

Nothing (unmodified, step will handle it)

s3://

Footnotes

1

References defined by opensearch:// will trigger an OpenSearch query using the provided URL as well as other input additional parameters (see OpenSearch Data Source). After processing of this query, retrieved file references will be re-processed using the summarized logic in the table for the given use case.

2(1,2,3,4,5)

When a file:// (or empty scheme) maps to a local file that needs to be exposed externally for another remote process, the conversion to http(s):// scheme employs setting weaver.wps_output_url to form the result URL reference. The file is placed in weaver.wps_output_dir to expose it as HTTP(S) endpoint. Note that the HTTP(S) servicing of the file is not handled by Weaver itself. It is assumed that the server where Weaver is hosted or another service takes care of this task.

3(1,2,3,4)

When the process refers to a remote WPS-REST process (i.e.: remote WPS instance that supports REST bindings but that is not necessarily an ADES), Weaver simply wraps and monitors its remote execution, therefore files are handled just as for any other type of remote WPS-like servers. When the process contains an actual CWL Application Package that defines a CommandLineTool class (including applications with Docker image requirement), files are fetched as it will be executed locally. See CWL CommandLineTool, WPS-REST and Remote Provider for further details.

4(1,2)

When an s3:// file is fetched, is gets downloaded to a temporary file:// location, which is NOT necessarily exposed as http(s)://. If execution is transferred to a remove process that is expected to not support S3 references, only then the file gets converted as in 2.

5(1,2)

Workflows are only available on EMS and HYBRID instances. Since they chain processes, no fetch is needed as the sub-step process will do it instead as needed. See Workflow process as well as CWL Workflow for more details.

Todo

method to indicate explicit fetch to override these? (https://github.com/crim-ca/weaver/issues/183)

Todo

add tests that validate each combination of operation

OpenSearch Data Source

In order to provide OpenSearch query results as input to Process for execution, the corresponding Deploy request body must be provided with additionalParameters in order to indicate how to interpret any specified metadata. The appropriate OpenSearch queries can then be applied prior the execution to retrieve the explicit file reference(s) of EOImage elements that have been found and to be submitted to the Job.

Depending on the desired context (application or per-input) over which the AOI, TOI, EOImage and multiple other metadata search filters are to be applied, their definition can be provided in the following locations within the Deploy body.

Context

Location

Role

Application

processDescription.process.additionalParameters

http://www.opengis.net/eoc/applicationContext

Input

processDescription.process.inputs[*].additionalParameters

http://www.opengis.net/eoc/applicationContext/inputMetadata

The distinction between application or per-input contexts is entirely dependent of whatever is the intended processing operation of the underlying Process, which is why they must be defined by the user deploying the process since there is no way for Weaver to automatically infer how to employ provided search parameters.

In each case, the structure of additionalParameters should be similar to the following definition:

{
  "additionalParameters": [
    {
      "role": "http://www.opengis.net/eoc/applicationContext/inputMetadata",
      "parameters": [
        {
          "name": "EOImage",
          "values": [
            "true"
          ]
        },
        {
          "name": "AllowedCollections",
          "values": "s2-collection-1,s2-collection-2,s2-sentinel2,s2-landsat8"
        }
      ]
    }
  ]
}

In each case, it is also expected that the role should correspond to the location where the definition is provided accordingly to their context from the above table.

For each deployment, processes using EOImage to be processed into OpenSearch query results can interpret the following field definitions for mapping against respective inputs or application context.

Name

Values

Context

Description

EOImage

["true"]

Input

Indicates that the nested parameters within the current additionalParameters section where it is located defines an EOImage. This is to avoid misinterpretation by similar names that could be employed by other kind of definitions. The Process input’s id where this parameter is defined is the name that will be employed to pass down OpenSearch results.

AllowedCollections

String of comma-separated list of collection IDs.

Input (same one as EOImage)

Provides a subset of collection identifiers that are supported. During execution any specified input not respecting one of the defined values will fail OpenSearch query resolution.

CatalogSearchField

["<name>"]

Input (other one than EOImage)

String with the relevant OpenSearch query filter name according to the described input. Defines a given Process input id to be mapped against the specified query name.

UniqueAOI

["true"]

Application

Indicates that provided CatalogSearchField (typically bbox) corresponds to a global AOI that should be respected across multiple EOImage inputs. Otherwise, (default values: ["false"]) each EOImage should be accompanied with its respective AOI definition.

UniqueTOI

["true"]

Application

Indicates that provided CatalogSearchField (typically StartDate and EndDate) corresponds to a global TOI that should be respected across multiple EOImage inputs. Otherwise, (default values: ["false"]) each EOImage should be accompanied with its respective TOI definition.

When an EOImage is detected for a given Process, any submitted Job execution will expect the defined inputs in the Process description to indicate which images to retrieve for the application. Using inputs defined with corresponding CatalogSearchField filters, a specific OpenSearch query will be sent to obtain the relevant images. The inputs corresponding to search fields will then be discarded following OpenSearch resolution. The resolved link(s) for to EOImage will be substituted within the id of the input where EOImage was specified and will be forwarded to the underlying Application Package for execution.

Note

Collection identifiers are mapped against URL endpoints defined in configuration to execute the appropriate OpenSearch requests. See Configuration of Data Sources for more details.

See also

Definitions in OpenSearch Deploy request body provides a more detailed example of the expected structure and relevant additionalParameters locations.

See also

Definitions in OpenSearch Examples providing different combinations of inputs, notably for using distinct AOI, term:TOI and collections, with or without UniqueAOI and UniqueTOI specifiers.

Multiple Inputs

Todo

repeating IDs example for WPS multi-inputs

Multiple Outputs

Although CWL allows output arrays, WPS does not support it directly, as only single values are allowed for WPS outputs according to original specification. To work around this, Metalink files can be used to provide a single output reference that embeds other references. This approach is also employed and preferred as described in PyWPS Multiple Outputs.

Todo

fix doc when Multiple Output is supported with metalink (https://github.com/crim-ca/weaver/issues/25)

Todo

add example of multi-output process definition

Todo

and how CWL maps them with WPS

Warning

This feature is being worked on (Weaver Issue #25). Direct support between

Outputs Location

By default, Job results will be hosted under the endpoint configured by weaver.wps_output_url and weaver.wps_output_path, and will be stored under directory defined by weaver.wps_output_dir setting.

Each Job will have its specific UUID employed for all of the outputs files, logs and status in order to avoid conflicts. Therefore, outputs will be available with the following location:

{WPS_OUTPUT_URL}/{JOB_UUID}.xml             # status location
{WPS_OUTPUT_URL}/{JOB_UUID}.log             # execution logs
{WPS_OUTPUT_URL}/{JOB_UUID}/{output.ext}    # results of the job if successful

Note

Value WPS_OUTPUT_URL in above example is resolved accordingly with weaver.wps_output_url, weaver.wps_output_path and weaver.url, as per Configuration Settings details.

When submitting a Job for execution, it is possible to provide the X-WPS-Output-Context header. This modifies the output location to be nested under the specified directory or sub-directories.

For example, providing X-WPS-Output-Context: project/test-1 will result in outputs located at:

{WPS_OUTPUT_URL}/project/test-1/{JOB_UUID}/{output.ext}

Note

Values provided by X-WPS-Output-Context can only contain alphanumeric, hyphens, underscores and path separators that will result in a valid directory and URL locations. The path is assumed relative by design to be resolved under the WPS output directory, and will therefore reject any . or .. path references. The path also CANNOT start by /. In such cases, an HTTP error will be immediately raised indicating the symbols that where rejected when detected within X-WPS-Output-Context header.

If desired, parameter weaver.wps_output_context can also be defined in the Configuration Settings in order to employ a default directory location nested under weaver.wps_output_dir when X-WPS-Output-Context header is omitted from the request. By default, this parameter is not defined (empty) in order to store Job results directly under the configured WPS output directory.

Note

Header X-WPS-Output-Context is ignored when using S3 buckets for output location since they are stored individually per Job UUID, and hold no relevant context location. See also Configuration of AWS S3 Buckets.

New in version 4.3.0: Addition of the X-WPS-Output-Context header.

Email Notification

When submitting a Job for execution, it is possible to provide the notification_email field. Doing so will tell Weaver to send an email to the specified address with successful or failure details upon Job completion. The format of the email is configurable from weaver.ini.example file with email-specific settings (see: Configuration).

Monitoring of a process (GetStatus)

Todo

job status body example (success vs fail)

Obtaining output results, logs or errors

In the case of successful Job execution, the outputs can be retrieved with GET {WEAVER_URL}/processes/{id}/jobs/{id}/result (GetResult) request to list each corresponding output id with the generated file reference URL. Keep in mind that those URL’s purpose are only to fetch the results (not persistent storage), and could therefore be purged after some reasonable amount of time. The format should be similar to the following example, with minor variations according to Configuration parameters for the base WPS output location:

{
  "outputs": [
    {
      "id": "output",
      "href": "{WEAVER_URL}/wpsoutputs/f93a15be-6e16-11ea-b667-08002752172a/output_netcdf.nc"
    }
  ]
}

In situations where the Job resulted into failed status, the GET {WEAVER_URL}/processes/{id}/jobs/{id}/exceptions (GetLogs) can be use to retrieve the potential cause of failure, by capturing any raised exception. Below is an example of such exception details.

[
  "builtins.Exception: Could not read status document after 5 retries. Giving up."
]

The returned exception are often better understood when compared against, or in conjunction with, the logs that provide details over each step of the operation.

Any Job executed by Weaver will provide minimal information log, such as operation setup, the moment when it started execution and latest status. The extent of other log entries will more often than not depend on the verbosity of the underlying process being executed. When executing an Application Package, Weaver tries as best as possible to collect standard output and error steams to report them through log and exception lists.

Since Weaver can only report as much details as provided by the running application, it is recommended by Application Package implementers to provide progressive status updates when developing their package in order to help understand problematic steps in event of process execution failures. In the case of remote WPS processes monitored by Weaver for example, this means gradually reporting process status updates (e.g.: calling WPSResponse.update_status if you are using PyWPS, see: Progress and Status Report), while using print and/or logging operation for scripts or Docker images executed through CWL CommandLineTool.

Note

Job logs and exceptions are a Weaver-specific implementation. They are not part of traditional OGC API - Processes.

A minimalistic example of logging output is presented below. This can be retrieved using GET {WEAVER_URL}/processes/{id}/jobs/{id}/logs (GetLogs) request, at any moment during Job execution (with logs up to that point in time) or after its completion (for full output). Note again that the more the Process is verbose, the more tracking will be provided here.

[
  "[2020-03-24 21:32:32] INFO     [weaver.datatype.Job] 0:00:00   1% accepted   Job task setup completed.",
  "[2020-03-24 21:32:32] INFO     [weaver.datatype.Job] 0:00:00   2% accepted   Execute WPS request for process [jsonarray2netcdf]",
  "[2020-03-24 21:32:33] INFO     [weaver.datatype.Job] 0:00:01   4% accepted   Fetching job input definitions.",
  "[2020-03-24 21:32:33] INFO     [weaver.datatype.Job] 0:00:01   6% accepted   Fetching job output definitions.",
  "[2020-03-24 21:32:33] INFO     [weaver.datatype.Job] 0:00:01   8% accepted   Starting job process execution",
  "[2020-03-24 21:32:34] INFO     [weaver.datatype.Job] 0:00:01  10% accepted   Verifying job status location.",
  "[2020-03-24 21:32:34] WARNING  [weaver.datatype.Job] 0:00:01  10% accepted   WPS status location could not be found",
  "[2020-03-24 21:32:34] INFO     [weaver.datatype.Job] 0:00:01  20% running    Starting monitoring of job execution.",
  "[2020-03-24 21:33:59] INFO     [weaver.datatype.Job] 0:01:26  90% succeeded  [2020-03-24 17:32:34] INFO     [wps_package.jsonarray2netcdf]    1% running    Preparing package logs done.",
  "[2020-03-24 21:33:59] INFO     [weaver.datatype.Job] 0:01:26  90% succeeded  [2020-03-24 17:32:34] INFO     [wps_package.jsonarray2netcdf]    2% running    Launching package...",
  "[2020-03-24 21:33:59] INFO     [weaver.datatype.Job] 0:01:26  90% succeeded  [2020-03-24 17:32:34] INFO     [cwltool] Resolved '/tmp/tmpse3pi1gj/jsonarray2netcdf' to 'file:///tmp/tmpse3pi1gj/jsonarray2netcdf'",
  "[2020-03-24 21:33:59] INFO     [weaver.datatype.Job] 0:01:26  90% succeeded  [2020-03-24 17:32:34] INFO     [cwltool] ../../../../../tmp/tmpse3pi1gj/jsonarray2netcdf:1:1: Unknown hint",
  "[2020-03-24 21:33:59] INFO     [weaver.datatype.Job] 0:01:26  90% succeeded                                                       file:///tmp/tmpse3pi1gj/BuiltinRequirement",
  "[2020-03-24 21:33:59] INFO     [weaver.datatype.Job] 0:01:26  90% succeeded  [2020-03-24 17:32:34] INFO     [wps_package.jsonarray2netcdf]    5% running    Loading package content done.",
  "[2020-03-24 21:33:59] INFO     [weaver.datatype.Job] 0:01:26  90% succeeded  [2020-03-24 17:32:34] INFO     [wps_package.jsonarray2netcdf]    6% running    Retrieve package inputs done.",
  "[2020-03-24 21:33:59] INFO     [weaver.datatype.Job] 0:01:26  90% succeeded  [2020-03-24 17:32:34] INFO     [wps_package.jsonarray2netcdf]    8% running    Convert package inputs done.",
  "[2020-03-24 21:33:59] INFO     [weaver.datatype.Job] 0:01:26  90% succeeded  [2020-03-24 17:32:34] INFO     [wps_package.jsonarray2netcdf]   10% running    Running package...",
  "[2020-03-24 21:33:59] INFO     [weaver.datatype.Job] 0:01:26  90% succeeded  [2020-03-24 17:32:34] INFO     [cwltool] [job jsonarray2netcdf] /tmp/tmpqy1t8dp3$ python \\",
  "[2020-03-24 21:33:59] INFO     [weaver.datatype.Job] 0:01:26  90% succeeded      /opt/weaver/processes/builtin/jsonarray2netcdf.py \\",
  "[2020-03-24 21:33:59] INFO     [weaver.datatype.Job] 0:01:26  90% succeeded      -o \\",
  "[2020-03-24 21:33:59] INFO     [weaver.datatype.Job] 0:01:26  90% succeeded      /tmp/tmpqy1t8dp3 \\",
  "[2020-03-24 21:33:59] INFO     [weaver.datatype.Job] 0:01:26  90% succeeded      -i \\",
  "[2020-03-24 21:33:59] INFO     [weaver.datatype.Job] 0:01:26  90% succeeded      /tmp/tmpla2utn2c/stgb5787338-4a34-4771-88c0-cae95f4d82dd/test_nc_array.json",
  "[2020-03-24 21:33:59] INFO     [weaver.datatype.Job] 0:01:26  90% succeeded  [2020-03-24 17:32:41] INFO     [cwltool] [job jsonarray2netcdf] Max memory used: 36MiB",
  "[2020-03-24 21:33:59] INFO     [weaver.datatype.Job] 0:01:26  90% succeeded  [2020-03-24 17:32:41] INFO     [cwltool] [job jsonarray2netcdf] completed success",
  "[2020-03-24 21:33:59] INFO     [weaver.datatype.Job] 0:01:26  90% succeeded  [2020-03-24 17:32:41] INFO     [wps_package.jsonarray2netcdf]   95% running    Package execution done.",
  "[2020-03-24 21:33:59] INFO     [weaver.datatype.Job] 0:01:26  90% succeeded  [2020-03-24 17:33:53] INFO     [wps_package.jsonarray2netcdf]   98% running    Generate package outputs done.",
  "[2020-03-24 21:33:59] INFO     [weaver.datatype.Job] 0:01:26  90% succeeded  [2020-03-24 17:33:55] INFO     [wps_package.jsonarray2netcdf]  100% succeeded  Package complete.",
  "[2020-03-24 21:33:59] INFO     [weaver.datatype.Job] 0:01:26  90% succeeded  Job succeeded (status: Package complete.).",
  "[2020-03-24 21:34:45] INFO     [weaver.datatype.Job] 0:01:26  90% succeeded  Job succeeded.",
  "[2020-03-24 21:34:45] INFO     [weaver.datatype.Job] 0:01:26 100% succeeded  Job task complete."
]

Special Weaver EMS use-cases

This section highlight the additional behaviour available only through an EMS-configured Weaver instance. Some other points are already described in other sections, but are briefly indicated here for conciseness.

ADES dispatching using Data-Sources

Todo

add details, data-source defines where to send request of known ADES

Todo

reference config weaver.data_sources

Workflow (Chaining Step Processes)

Todo

add details, explanation done in below reference

See also