Communicate timeouts

[m-mohr]

Google returns HTTP status 400 with a text response Computation timed out. if the data is too big to process. This is currently not communicated very well and should be improved.

Related to Simons issue with the following process graph:

{
  "process_graph": {
    "imagery": {
      "red": "B4",
      "nir": "B8A",
      "imagery": {
        "extent": [
          "2018-01-01T00:00:00Z",
          "2018-12-31T23:59:59Z"
        ],
        "imagery": {
          "extent": {
            "west": 4.757069,
            "south": 51.502332,
            "east": 6.020497,
            "north": 52.849645
          },
          "imagery": {
            "process_id": "get_collection",
            "name": "COPERNICUS/S2"
          },
          "process_id": "filter_bbox"
        },
        "process_id": "filter_daterange"
      },
      "process_id": "NDVI"
    },
    "process_id": "max_time"
  },
  "budget": null,
  "output": {
    "format": "png",
    "parameters": {}
  }
}

He also says that the batch job behaves not very well:

Der Batch-Job läuft auch irgendwie nicht durch. Er antwortet mit „Job has not finished computing the results yet“ und nach einiger Zeit kommt dann sogar „Job has not been startet yet“.

[m-mohr]

This should be solved with version 0.4.