.. _swh-graph-api: Graph Querying HTTP API ======================= The Graph Querying API is a high-level HTTP API intended to run common, relatively simple traversal queries on the compressed graph. The client/server architecture allows it to only load the graph in memory once then serve multiple different requests. However, it is limited in expressivity; more complex or resource-intensive queries should rather use the :ref:`Low-level Java API ` to run them as standalone programs. Terminology ----------- This API uses the following notions: - **Node**: a node in the :ref:`Software Heritage graph `, represented by a :ref:`SWHID `. - **Node type**: the 3-letter specifier from the node SWHID (``cnt``, ``dir``, ``rel``, ``rev``, ``snp``, ``ori``), or ``*`` for all node types. - **Edge type**: a pair ``src:dst`` where ``src`` and ``dst`` are either node types, or ``*`` to denote all node types. - **Edge restrictions**: a textual specification of which edges can be followed during graph traversal. Either ``*`` to denote that all edges can be followed or a comma separated list of edge types to allow following only those edges. Note that when traversing the *backward* (i.e., transposed) graph, edge types are reversed too. So, for instance, ``ori:snp`` makes sense when traversing the forward graph, but useless (due to lack of matching edges in the graph) when traversing the backward graph; conversely ``snp:ori`` is useful when traversing the backward graph, but not in the forward one. For the same reason ``dir:dir`` allows following edges from parent directories to sub-directories when traversing the forward graph, but the same restriction allows following edges from sub-directories to parent directories. - **Node restrictions**: a textual specification of which type of nodes can be returned after a request. Either ``*`` to denote that all types of nodes can be returned or a comma separated list of node types to allow returning only those node types. Examples ~~~~~~~~ - ``swh:1:cnt:94a9ed024d3859793618152ea559a168bbcbb5e2`` the SWHID of a node of type content containing the full text of the GPL3 license. - ``swh:1:rev:f39d7d78b70e0f39facb1e4fab77ad3df5c52a35`` the SWHID of a node of type revision corresponding to the commit in Linux that merged the 'x86/urgent' branch on 31 December 2017. - ``"dir:dir,dir:cnt"`` node types allowing edges from directories to directories nodes, or directories to contents nodes. - ``"rev:rev,dir:*"`` node types allowing edges from revisions to revisions nodes, or from directories nodes. - ``"*:rel"`` node types allowing all edges to releases. - ``"cnt,snp"`` accepted node types returned in the query results. Endpoints --------- Leaves ~~~~~~ .. http:get:: /graph/leaves/:src Performs a graph traversal and returns the leaves of the subgraph rooted at the specified source node. :param string src: source node specified as a SWHID :query string edges: edges types the traversal can follow; default to ``"*"`` :query string direction: direction in which graph edges will be followed; can be either ``forward`` or ``backward``, default to ``forward`` :query integer max_edges: how many edges can be traversed during the visit; default to 0 (not restricted) :query string return_types: only return the nodes matching this type; default to ``"*"`` :query integer max_matching_nodes: how many results to return before stopping; default to 0 (not restricted) :statuscode 200: success :statuscode 400: invalid query string provided :statuscode 404: starting node cannot be found **Example:** .. sourcecode:: http GET /graph/leaves/swh:1:dir:432d1b21c1256f7408a07c577b6974bbdbcc1323 HTTP/1.1 Content-Type: text/plain Transfer-Encoding: chunked .. sourcecode:: http HTTP/1.1 200 OK swh:1:cnt:540faad6b1e02e2db4f349a4845192db521ff2bd swh:1:cnt:630585fc6d34e5e121139e2aee0a64e83dc9aae6 swh:1:cnt:f8634ced669f0a9155c8cab1b2621d57d778215e swh:1:cnt:ba6daa801ad3ea587904b1abe9161dceedb2e0bd ... Neighbors ~~~~~~~~~ .. http:get:: /graph/neighbors/:src Returns node direct neighbors (linked with exactly one edge) in the graph. :param string src: source node specified as a SWHID :query string edges: edges types allowed to be listed as neighbors; default to ``"*"`` :query string direction: direction in which graph edges will be followed; can be either ``forward`` or ``backward``, default to ``forward`` :query integer max_edges: how many edges can be traversed during the visit; default to 0 (not restricted) :query string return_types: only return the nodes matching this type; default to ``"*"`` :statuscode 200: success :statuscode 400: invalid query string provided :statuscode 404: starting node cannot be found **Example:** .. sourcecode:: http GET /graph/neighbors/swh:1:rev:f39d7d78b70e0f39facb1e4fab77ad3df5c52a35 HTTP/1.1 Content-Type: text/plain Transfer-Encoding: chunked .. sourcecode:: http HTTP/1.1 200 OK swh:1:rev:a31e58e129f73ab5b04016330b13ed51fde7a961 swh:1:dir:b5d2aa0746b70300ebbca82a8132af386cc5986d swh:1:rev:52c90f2d32bfa7d6eccd66a56c44ace1f78fbadd ... Walk ~~~~ .. .. http:get:: /graph/walk/:src/:dst Performs a graph traversal and returns the first found path from source to destination (final destination node included). :param string src: starting node specified as a SWHID :param string dst: destination node, either as a node SWHID or a node type. The traversal will stop at the first node encountered matching the desired destination. :query string edges: edges types the traversal can follow; default to ``"*"`` :query string traversal: traversal algorithm; can be either ``dfs`` or ``bfs``, default to ``dfs`` :query string direction: direction in which graph edges will be followed; can be either ``forward`` or ``backward``, default to ``forward`` :query string return_types: types of nodes we want to be displayed; default to ``"*"`` :statuscode 200: success :statuscode 400: invalid query string provided :statuscode 404: starting node cannot be found **Example:** .. sourcecode:: http HTTP/1.1 200 OK swh:1:rev:f39d7d78b70e0f39facb1e4fab77ad3df5c52a35 swh:1:rev:52c90f2d32bfa7d6eccd66a56c44ace1f78fbadd swh:1:rev:cea92e843e40452c08ba313abc39f59efbb4c29c swh:1:rev:8d517bdfb57154b8a11d7f1682ecc0f79abf8e02 ... Visit ~~~~~ .. http:get:: /graph/visit/nodes/:src .. http:get:: /graph/visit/edges/:src Performs a graph traversal and returns explored nodes, edges or paths (in the order of the traversal). :param string src: starting node specified as a SWHID :query string edges: edges types the traversal can follow; default to ``"*"`` :query integer max_edges: how many edges can be traversed during the visit; default to 0 (not restricted) :query string return_types: only return the nodes matching this type; default to ``"*"`` :query integer max_matching_nodes: how many nodes to return/visit before stopping; default to 0 (not restricted) :statuscode 200: success :statuscode 400: invalid query string provided :statuscode 404: starting node cannot be found **Example:** .. sourcecode:: http GET /graph/visit/nodes/swh:1:snp:40f9f177b8ab0b7b3d70ee14bbc8b214e2b2dcfc HTTP/1.1 Content-Type: text/plain Transfer-Encoding: chunked .. sourcecode:: http HTTP/1.1 200 OK swh:1:snp:40f9f177b8ab0b7b3d70ee14bbc8b214e2b2dcfc swh:1:rev:cfab784723a6c2d33468c9ed8a566fd5e2abd8c9 swh:1:rev:53e5df0e7a6b7bd4919074c081a173655c0da164 swh:1:rev:f85647f14b8243532283eff3e08f4ee96c35945f swh:1:rev:fe5f9ef854715fc59b9ec22f9878f11498cfcdbf swh:1:dir:644dd466d8ad527ea3a609bfd588a3244e6dafcb swh:1:cnt:c8cece50beae7a954f4ea27e3ae7bf941dc6d0c0 swh:1:dir:a358d0cf89821227d4c00b0ced5e0a8b3756b5db swh:1:cnt:cc407b7e24dd300d2e1a77d8f04af89b3f962a51 swh:1:cnt:701bd0a63e11b3390a547ce8515d28c6bab8a201 ... **Example:** .. sourcecode:: http GET /graph/visit/edges/swh:1:snp:40f9f177b8ab0b7b3d70ee14bbc8b214e2b2dcfc HTTP/1.1 Content-Type: text/plain Transfer-Encoding: chunked .. sourcecode:: http HTTP/1.1 200 OK swh:1:snp:40f9f177b8ab0b7b3d70ee14bbc8b214e2b2dcfc swh:1:rev:61f92a7db95f5a6d1fcb94d2b897ed3797584d7b swh:1:snp:40f9f177b8ab0b7b3d70ee14bbc8b214e2b2dcfc swh:1:rev:00e81c89c29ff3e58745fdaf7abb68daa1389e85 swh:1:snp:40f9f177b8ab0b7b3d70ee14bbc8b214e2b2dcfc swh:1:rev:7596fdc31c9aa00aed281ccb026a74cabf2383bb swh:1:snp:40f9f177b8ab0b7b3d70ee14bbc8b214e2b2dcfc swh:1:rev:ec7a2341ac3d9d8b571bbdfb90a089d4e54dea56 swh:1:snp:40f9f177b8ab0b7b3d70ee14bbc8b214e2b2dcfc swh:1:rev:1c5b5eac61eda2454034a43eb124ab490885ef3a swh:1:snp:40f9f177b8ab0b7b3d70ee14bbc8b214e2b2dcfc swh:1:rev:4dfa88ca55e04e8afe05e8543ddddee32dde7236 swh:1:snp:40f9f177b8ab0b7b3d70ee14bbc8b214e2b2dcfc swh:1:rev:d56ae79e43ff1b37534370911c8a78ec7f38d437 swh:1:snp:40f9f177b8ab0b7b3d70ee14bbc8b214e2b2dcfc swh:1:rev:19ba5d6203a040a39ecc4a77b165d3f097c1e662 swh:1:snp:40f9f177b8ab0b7b3d70ee14bbc8b214e2b2dcfc swh:1:rev:9c56102eefea23c95405533e1de23da4b873ecc4 swh:1:snp:40f9f177b8ab0b7b3d70ee14bbc8b214e2b2dcfc swh:1:rev:3f54e816b46c2e179cd164e17fea93b3013a9db4 ... Counting results ~~~~~~~~~~~~~~~~ The following method variants, with trailing `/count` added, behave like their already discussed counterparts but, instead of returning results, return the *amount* of results that would have been returned: .. http:get:: /graph/leaves/count/:src Return the amount of :http:get:`/graph/leaves/:src` results .. http:get:: /graph/neighbors/count/:src Return the amount of :http:get:`/graph/neighbors/:src` results .. http:get:: /graph/visit/nodes/count/:src Return the amount of :http:get:`/graph/visit/nodes/:src` results Stats ~~~~~ .. http:get:: /graph/stats Returns statistics on the compressed graph. :statuscode 200: success **Example** .. sourcecode:: http GET /graph/stats HTTP/1.1 Content-Type: application/json .. sourcecode:: http HTTP/1.1 200 OK { "counts": { "nodes": 16222788, "edges": 9907464 }, "ratios": { "compression": 0.367, "bits_per_node": 5.846, "bits_per_edge": 9.573, "avg_locality": 270.369 }, "indegree": { "min": 0, "max": 12382, "avg": 0.6107127825377487 }, "outdegree": { "min": 0, "max": 1, "avg": 0.6107127825377487 } } Use-case examples ----------------- This section showcases how to leverage the endpoints of the HTTP API described above for some common use-cases. Browsing ~~~~~~~~ The following use cases require traversing the *forward graph*. - **ls**: given a directory node, list (non recursively) all linked nodes of type directory and content Endpoint:: /graph/neighbors/:DIR_ID?edges=dir:cnt,dir:dir - **git log**: given a revision node, recursively list all linked nodes of type revision Endpoint:: /graph/visit/nodes/:REV_ID?edges=rev:rev Vault ~~~~~ The following use cases require traversing the *forward graph*. - **tarball** (same as *ls -R* above) - **git bundle**: given a node, recursively list all linked nodes of any kind Endpoint:: /graph/visit/nodes/:NODE_ID?edges=* Provenance ~~~~~~~~~~ The following use cases require traversing the *backward (transposed) graph*. - **commit provenance**: given a content or directory node, return *a* commit whose directory (recursively) contains it Endpoint:: /graph/walk/:NODE_ID/rev?direction=backward&edges=dir:dir,cnt:dir,dir:rev - **complete commit provenance**: given a content or directory node, return *all* commits whose directory (recursively) contains it Endpoint:: /graph/leaves/:NODE_ID?direction=backward&edges=dir:dir,cnt:dir,dir:rev - **origin provenance**: given a content, directory, or commit node, return *an* origin that has at least one snapshot that (recursively) contains it Endpoint:: /graph/walk/:NODE_ID/ori?direction=backward&edges=* - **complete origin provenance**: given a content, directory, or commit node, return *all* origins that have at least one snapshot that (recursively) contains it Endpoint:: /graph/leaves/:NODE_ID?direction=backward&edges=* Provenance statistics ~~~~~~~~~~~~~~~~~~~~~ The following use cases require traversing the *backward (transposed) graph*. - **content popularity across commits**: count the number of commits (or *commit popularity*) that link to a directory that (recursively) includes a given content. Endpoint:: /graph/count/leaves/:NODE_ID?direction=backward&edges=cnt:dir,dir:dir,dir:rev - **commit popularity across origins**: count the number of origins (or *origin popularity*) that have a snapshot that (recursively) includes a given commit. Endpoint:: /graph/count/leaves/:NODE_ID?direction=backward&edges=* The following use cases require traversing the *forward graph*. - **revision size** (as n. of contents) distribution: the number of contents that are (recursively) reachable from a given revision. Endpoint:: /graph/count/leaves/:NODE_ID?edges=* - **origin size** (as n. of revisions) distribution: count the number of revisions that are (recursively) reachable from a given origin. Endpoint:: /graph/count/leaves/:NODE_ID?edges=ori:snp,snp:rel,snp:rev,rel:rev,rev:rev