Render Eliot logs as an ASCII tree.

This output:

$ eliot-tree eliot.log
f3a32bb3-ea6b-457c-aa99-08a3d0491ab4
+-- app:soap:client:request@1/started
    |-- dump: /home/user/dump_files/20150303/1425356936.28_Client_req.xml
    |-- soapAction: a_soap_action
    |-- timestamp: 2015-03-03 06:28:56.278875
    `-- uri: http://example.org/soap
    +-- app:soap:client:success@2,1/started
        `-- timestamp: 2015-03-03 06:28:57.516579
        +-- app:soap:client:success@2,2/succeeded
            |-- dump: /home/user/dump_files/20150303/1425356937.52_Client_res.xml
            `-- timestamp: 2015-03-03 06:28:57.517077
    +-- app:soap:client:request@3/succeeded
        |-- status: 200
        `-- timestamp: 2015-03-03 06:28:57.517161

89a56df5-d808-4a7c-8526-e603aae2e2f2
+-- app:soap:service:request@1/started
    |-- dump: /home/user/dump_files/20150303/1425357068.03_Service_req.xml
    |-- soapAction: method
    |-- timestamp: 2015-03-03 06:31:08.032091
    `-- uri: /endpoints/soap/method
    +-- app:soap:service:success@2,1/started
        `-- timestamp: 2015-03-03 06:31:11.512330
        +-- app:soap:service:success@2,2/succeeded
            |-- dump: /home/user/dump_files/20150303/1425357071.51_Service_res.xml
            `-- timestamp: 2015-03-03 06:31:11.513453
    +-- app:soap:service:request@3/succeeded
        |-- status: 200
        `-- timestamp: 2015-03-03 06:31:11.513992

was generated from:

{"dump": "/home/user/dump_files/20150303/1425356936.28_Client_req.xml", "timestamp": 1425356936.278875, "uri": "http://example.org/soap", "action_status": "started", "task_uuid": "f3a32bb3-ea6b-457c-aa99-08a3d0491ab4", "action_type": "app:soap:client:request", "soapAction": "a_soap_action", "task_level": [1]}
{"timestamp": 1425356937.516579, "task_uuid": "f3a32bb3-ea6b-457c-aa99-08a3d0491ab4", "action_type": "app:soap:client:success", "action_status": "started", "task_level": [2, 1]}
{"task_uuid": "f3a32bb3-ea6b-457c-aa99-08a3d0491ab4", "action_type": "app:soap:client:success", "dump": "/home/user/dump_files/20150303/1425356937.52_Client_res.xml", "timestamp": 1425356937.517077, "action_status": "succeeded", "task_level": [2, 2]}
{"status": 200, "task_uuid": "f3a32bb3-ea6b-457c-aa99-08a3d0491ab4", "task_level": [3], "action_type": "app:soap:client:request", "timestamp": 1425356937.517161, "action_status": "succeeded"}
{"dump": "/home/user/dump_files/20150303/1425357068.03_Service_req.xml", "timestamp": 1425357068.032091, "uri": "/endpoints/soap/method", "action_status": "started", "task_uuid": "89a56df5-d808-4a7c-8526-e603aae2e2f2", "action_type": "app:soap:service:request", "soapAction": "method", "task_level": [1]}
{"timestamp": 1425357071.51233, "task_uuid": "89a56df5-d808-4a7c-8526-e603aae2e2f2", "action_type": "app:soap:service:success", "action_status": "started", "task_level": [2, 1]}
{"task_uuid": "89a56df5-d808-4a7c-8526-e603aae2e2f2", "action_type": "app:soap:service:success", "dump": "/home/user/dump_files/20150303/1425357071.51_Service_res.xml", "timestamp": 1425357071.513453, "action_status": "succeeded", "task_level": [2, 2]}
{"status": 200, "task_uuid": "89a56df5-d808-4a7c-8526-e603aae2e2f2", "task_level": [3], "action_type": "app:soap:service:request", "timestamp": 1425357071.513992, "action_status": "succeeded"}

usage: eliot-tree [-h] [-u UUID] [-i KEY] [--raw] [-l LENGTH] [--select QUERY]
                  [FILE [FILE ...]]

Display an Eliot log as a tree of tasks.

positional arguments:
  FILE                  Files to process

optional arguments:
  -h, --help            show this help message and exit
  -u UUID, --task-uuid UUID
                        Select a specific task by UUID
  -i KEY, --ignore-task-key KEY
                        Ignore a task key, use multiple times to ignore
                        multiple keys. Defaults to ignoring most Eliot
                        standard keys.
  --raw                 Do not format some task values (such as timestamps) as
                        human-readable
  -l LENGTH, --field-limit LENGTH
                        Limit the length of field values to LENGTH or a
                        newline, whichever comes first. Use a length of 0 to
                        output the complete value.
  --select QUERY        Select tasks to be displayed based on a jmespath
                        query, can be specified multiple times to mimic
                        logical AND. If any child task is selected the entire
                        top-level task is selected. See <http://jmespath.org/>

See <https://github.com/jonathanj/eliottree> for details.