Update README

README.md

-# Deduped map tilelist
+# WMF maps tools
+
+A collection of maps related CLI utils written in python.
+
+## Dependencies
+
+- Python >= 3.7
+- PyYAML
+- PyOsmium
+- Psycopg 2
+
+## Releases
+
+Project releases are created automatically when a new tag is created. To create a new release with proper packaging:
+
+- Bump the version under `setup.py`
+- Bump the version under `debian/changelog`
+- Push a new tag with the changes
+
+## Deduped map tilelist
 
 Given an input file with a list of line seperated tiles in `{zoom}/{x}/{y}` format, generate a distinct list of map tiles for all zoom levels from `minzoom` up to `maxzoom`.
 
-## Usage
+### Usage
 
 ```
 usage: maps-deduped-tilelist [-h] minzoom maxzoom [tilelist_file]
@@ -18,7 +37,7 @@ optional arguments:
   -h, --help     show this help message and exit
 ```
 
-## Example
+### Example
 
 ```
 > cat tilelist.txt
@@ -48,18 +67,24 @@ optional arguments:
 1/1/1
 ```
 
-## Context
+### Context
 
 This CLI tool is built as a way to generate a deduplicated tile list of distinct tiles based on the `imposm3` expired tile output. The reason behind this is to deduplicate tiles and optimize tile pregeneration by avoiding generating the same tile multiple times.
 
-## Dependencies
+## Imposm changeset verifier
 
-- Python >= 3.7
+Given an OSM changeset file and an imposm mapping, verify that operations described in the changeset are reflected in the DB after an OSM sync
 
-## Releases
+### Usage
+```
+usage: imposm-changeset-verify [-h] [--failfast] changeset mapping pgURL
 
-Project releases are created automatically when a new tag is created. To create a new release with proper packaging:
+positional arguments:
+  changeset
+  mapping
+  pgURL
 
-- Bump the version under `setup.py`
-- Bump the version under `debian/changelog`
-- Push a new tag with the changes
+optional arguments:
+  -h, --help  show this help message and exit
+  --failfast
+```
\ No newline at end of file

wmfmaps/changeset/verifier.py

+import json
 import osmium
 import psycopg2
 import yaml
@@ -27,20 +28,28 @@ class ElementHandler:
                     raise InconsistentChangeException(
                         f"Element with id:{change.id} shouldn't exist"
                     )
-                self.inconsistencies.append(change.id)
+                self.inconsistencies.append(
+                    {"type": "should be deleted", "id": change.id}
+                )
+                break
 
     def verify_existing(self, change):
+        at_least_once = False
         for table in self.tables:
-            if not self.exists(table, change.id):
-                if self.failfast:
-                    raise InconsistentChangeException(
-                        f"Element with id:{change.id} should exist"
-                    )
-                self.inconsistencies.append(change.id)
+            if self.exists(table, change.id):
+                at_least_once = True
+                break
+
+        if not at_least_once:
+            if self.failfast:
+                raise InconsistentChangeException(
+                    f"Element with id:{change.id} should exist"
+                )
+            self.inconsistencies.append({"type": "should exist", "id": change.id})
 
     def log_inconsistencies(self):
         for elem in self.inconsistencies:
-            print(f"Inconsistency with OSM ID: {elem}")
+            print(f"{json.dumps(elem)}")
 
     def __call__(self, change):
         if change.deleted: