2 * The checker provides an api/tool for the verification of TOSCA yaml files
3 * as specified in the OASIS specification found at:
4 * http://docs.oasis-open.org/tosca/TOSCA-Simple-Profile-YAML/v1.0/TOSCA-Simple-Profile-YAML-v1.0.pdf
6 * It provides a three stage processing of a tosca yaml file:
7 * - yaml verification: is the document a valid yaml document as per yaml.org/spec. In particular we're using the snakeyaml library for parsing the yaml document to a nested structure of java objects.
8 * - tosca yaml grammar validation: is the document a valid tosca yaml
9 * document, as per the the TOSCA simple profile for yaml. We use a modified
10 * version of the kwalify library for this task. The grammar for TOSCA yaml
11 * is itself a yaml document (found in the package in
12 * resources/tosca-schema.yaml). There are certain limitations on how far
13 * this grammar can go.
14 * - consistency verification: we check the type hierarchies for all TOSCA
15 * constructs (data types, capability types, node types, etc), the definition
16 * of all facets of a construct (properties, attributes, etc) across the type
17 * hierachies, the conformity of construct templates (node templates, ..) with
18 * their types, data valuations(input assignements, constants, function calls).
20 * Each stage is blocking, i.e. a stage will be performed only if the previous
21 * one completed successfully.
23 * The verification is done across all the imported documents. The common TOSCA
24 * types are by default made available to all documents being processed (the
25 * specification is in resources/tosca-common-types.yaml). Networking related
26 * types can be made available by importing resources/tosca-network-types.yaml
27 * while the tosca nfv profile definitions are available at
28 * resources/tosca-nfv-types.yaml.
30 * Besides snakeyaml and kwalify this package also has dependencies on Google's
31 * guava library and Apache's jxpath.
33 * The three java interfaces exposed by the package are the Checker, Target
34 * and Report. A Target represents a document processed by the Checker. While
35 * the Checker starts with a top Target, through import statements it can end up
36 * processing a number of Targets. The results of processing a Target are made
37 * available through a Report which currently is nothing more that a list of
42 * Checker checker = new Checker();
43 * checker.check("tests/example.yaml");
45 * for (Target t: checker.targets())
46 * System.out.println(t.getLocation() + "\n" + t.getReport());
50 * The errors are recorded as instances of Exception, mostly due to the fact
51 * snakeyaml and kwalify do report errors as exceptions. As such there are 3
52 * basic types of errros to be expected in a report: YAMLException (from
53 * snakeyaml, related to parsing), ValidationException (from kwalify, tosca
54 * grammar validation), TargetException (from the checker itself). This might
55 * change as we're looking to unify the way errors are reported. A Report
56 * object has a user friendly toString function.
58 * A CheckerException thrown during the checking process is an indication of a
59 * malfunction in the checker itself.
61 * The checker handles targets as URIs. The resolution of a target consists in
62 * going from a string representing some path/uri to the absolute URI. URIs can
63 * be of any java recognizable schema: file, http, etc. A TargetResolver (not
64 * currently exposed through the API) attempts in order:
65 * - if the String is an absolute URI, keep it as such
66 * - if the String is a relative URI attempt to resolve it as relative to
67 * know search paths (pre-configured absolute URIs: current directory and the
68 * root of the main target's URI). The option of adding custom search paths will
70 * - attempt to resolve as a classpath resource (a jar:file: URI)
72 * At this time there are no options for the checker (please provide
73 * requirements to be considered).
78 * - the checker performs during tosca grammar validation a 'normalization'
79 * process as the tosca yaml profile allows for short forms in the
80 * specification of a number of its constructs (see spec). The checker changes
81 * the actual structure of the parsed document such that only normalized
82 * (complete) forms of specification are present before the checking phase.
83 * (the kwalify library was extended in order to be able to specify these
84 * short forms in the grammar itself and process/tolerate them at validation
87 * - the checker contains an internal catalog where the types and templates
88 * of different constructs are aggregated and indexed across all targets in
89 * order to facilitate the checking phase. Catalogs can be 'linked' and the
90 * resolution process delegated (the checker maintains a basic catalog with
91 * the core and common types and there is always a second catalog maintaining
92 * the information related to the current targets).
93 * The catalog is currently not exposed by the library.
95 * - imports processing: the import statements present in a target are first
96 * 'detected' during tosca yaml grammar validation phase. At that stage all
97 * imports are (recursively) parsed and validated (first 2 phases). Checking
98 * off all imports (recursively) is done during stage 3.
101 package org.onap.sdc.dcae.checker;