Initial commit

README.md

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+# nomad-diff
+
+A one to one Python re-write of the Job diff formatter [from Nomad's source](https://github.com/hashicorp/nomad/blob/v0.12.3/command/job_plan.go#L371).
+Use this if you communicate with Nomad over HTTP API and want to output the diff in the same format like the Nomad CLI & UI does.
+
+## Installation
+
+```
+$ pip install nomad-diff
+```
+
+## Usage
+
+```
+>>> import nomad_diff
+>>>
+>>> data = .. # Nomad's job diff
+>>>
+>>> print(nomad_diff.format(data, colors=True, verbose=False))
++/- Job: "example"
++/- Task Group: "cache" (2 destroy, 1 in-place update)
+  +/- Count: "3" => "1" (forces destroy)
+      Task: "redis"
+```
+

nomad_diff/__init__.py

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+from .diff import format_job_diff, JobDiff
+from colorama import Fore, Style  # type: ignore
+
+
+COLORS = {
+    '[green]': Fore.GREEN,
+    '[red]': Fore.RED,
+    '[blue]': Fore.BLUE,
+    '[cyan]': Fore.CYAN,
+    '[yellow]': Fore.YELLOW,
+    '[light_yellow]': Fore.LIGHTYELLOW_EX,
+    '[bold]': Style.BRIGHT,
+    '[reset]': Style.RESET_ALL
+}
+
+
+def format(diff: dict, colors: bool, verbose: bool):
+    diff_dict = JobDiff(**diff)
+    out = format_job_diff(diff_dict, verbose)
+
+    if not colors:
+        return strip_colors(out)
+
+    return colorize(out)
+
+
+def strip_colors(diff: str):
+    for e in COLORS.keys():
+        diff = diff.replace(e, '')
+
+    return diff
+
+
+def colorize(diff: str):
+    for p, color in COLORS.items():
+        diff = diff.replace(p, color)
+
+    return diff

nomad_diff/diff.py

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+from typing import List, Optional, Tuple
+from .models import JobDiff, TaskGroupDiff, FieldDiff, ObjectDiff, TaskDiff
+
+
+# https://github.com/hashicorp/nomad/blob/v0.12.3/command/job_plan.go#L371
+def format_job_diff(job: JobDiff, verbose: bool) -> str:
+    marker, _ = get_diff_string(job.Type)
+    out = f'{marker}[bold]Job: "{job.ID}"\n'
+
+    # Determine the longest markers and fields so that the output can be
+    # properly aligned.
+    longest_field, longest_marker = get_longest_prefixes(job.Fields, job.Objects)
+    for tg in job.TaskGroups or []:
+        _, l = get_diff_string(tg.Type)
+        if l > longest_marker:
+            longest_marker = l
+
+    # Only show the job's field and object diffs if the job is edited or
+    # verbose mode is set.
+    if job.Type == "Edited" or verbose:
+        fo = aligned_field_and_objects(job.Fields, job.Objects, 0, longest_field, longest_marker)
+        out += fo
+        if len(fo) > 0:
+            out += "\n"
+
+    # Print the task groups
+    for tg in job.TaskGroups or []:
+        _, mLength = get_diff_string(tg.Type)
+        kPrefix = longest_marker - mLength
+        out += f'{format_task_group_diff(tg, kPrefix, verbose)}\n'
+
+    return out
+
+
+# https://github.com/hashicorp/nomad/blob/v0.12.3/command/job_plan.go#L408
+def format_task_group_diff(tg: TaskGroupDiff, tg_prefix: int, verbose: bool) -> str:
+    marker, _ = get_diff_string(tg.Type)
+    out = f'{marker}{" " * tg_prefix}[bold]Task Group: "{tg.Name}"[reset]'
+
+    if tg.Updates:
+        order = list(tg.Updates.keys())
+        order.sort()
+
+        updates = []
+        for update_type in order:
+            count = tg.Updates[update_type]
+            color = ""
+
+            if update_type == "ignore" or update_type == "create":
+                color = "[green]"
+            elif update_type == "destroy":
+                color = "[red]"
+            elif update_type == "migrate":
+                color = "[blue]"
+            elif update_type == "in-place update":
+                color = "[cyan]"
+            elif update_type == "create/destroy update":
+                color = "[yellow]"
+            elif update_type == "canary":
+                color = "[light_yellow]"
+
+            updates.append(f'[reset]{color}{count} {update_type}')
+        out += f' ({", ".join(updates)}[reset])\n'
+    else:
+        out += "[reset]\n"
+
+    # Determine the longest field and markers so the output is properly
+    # aligned
+    longest_field, longest_marker = get_longest_prefixes(tg.Fields, tg.Objects)
+    for task in tg.Tasks or []:
+        _, l = get_diff_string(task.Type)
+        if l > longest_marker:
+            longest_marker = l
+
+    # Only show the task groups's field and object diffs if the group is edited or
+    # verbose mode is set.
+    sub_start_prefix = tg_prefix + 2
+    if tg.Type == "Edited" or verbose:
+        fo = aligned_field_and_objects(tg.Fields, tg.Objects, sub_start_prefix, longest_field, longest_marker)
+        out += fo
+        if len(fo) > 0:
+            out += "\n"
+
+    # Output the tasks
+    for task in tg.Tasks or []:
+        _, mLength = get_diff_string(task.Type)
+        prefix = longest_marker - mLength
+        out += f'{format_task_diff(task, sub_start_prefix, prefix, verbose)}'
+
+    return out
+
+
+# https://github.com/hashicorp/nomad/blob/v0.12.3/command/job_plan.go#L481
+def format_task_diff(task: TaskDiff, startPrefix: int, taskPrefix: int, verbose: bool) -> str:
+    marker, _ = get_diff_string(task.Type)
+    out = f'{" " * startPrefix}{marker}{" " * taskPrefix}[bold]Task: "{task.Name}"'
+
+    if task.Annotations:
+        out += f' [reset]({color_annotations(task.Annotations)})'
+
+    if task.Type == "None":
+        return out
+    elif task.Type in ("Deleted", "Added") and not verbose:
+        # Exit early if the job was not edited and it isn't verbose output
+        return out
+    else:
+        out += "\n"
+
+    sub_start_prefix = startPrefix + 2
+    longest_field, longest_marker = get_longest_prefixes(task.Fields, task.Objects)
+    out += aligned_field_and_objects(task.Fields, task.Objects, sub_start_prefix, longest_field, longest_marker)
+
+    return out
+
+
+# https://github.com/hashicorp/nomad/blob/v0.12.3/command/job_plan.go#L507
+def format_object_diff(diff: ObjectDiff, start_prefix: int, key_prefix: int) -> str:
+    start = " " * start_prefix
+    marker, markerLen = get_diff_string(diff.Type)
+    out = f'{start}{marker}{" " * key_prefix}{diff.Name} {{\n'
+
+    # Determine the length of the longest name and longest diff marker to
+    # properly align names and values
+    longest_field, longest_marker = get_longest_prefixes(diff.Fields, diff.Objects)
+    sub_start_prefix = start_prefix + key_prefix + 2
+    out += aligned_field_and_objects(diff.Fields, diff.Objects, sub_start_prefix, longest_field, longest_marker)
+
+    endprefix = " " * (start_prefix + markerLen + key_prefix)
+    return f'{out}\n{endprefix}}}'
+
+
+# https://github.com/hashicorp/nomad/blob/v0.12.3/command/job_plan.go#L526
+def format_field_diff(diff: FieldDiff, start_prefix: int, key_prefix: int, value_prefix: int) -> str:
+    marker, _ = get_diff_string(diff.Type)
+    out = f'{" " * start_prefix}{marker}{" " * key_prefix}{diff.Name}: {" " * value_prefix}'
+
+    if diff.Type == "Added":
+        out += f'"{diff.New}"'
+    elif diff.Type == "Deleted":
+        out += f'"{diff.Old}"'
+    elif diff.Type == "Edited":
+        out += f'"{diff.Old}" => "{diff.New}"'
+    else:
+        out += f'"{diff.New}"'
+
+    # Color the annotations where possible
+    if diff.Annotations:
+        out += f' ({color_annotations(diff.Annotations)})'
+
+    return out
+
+
+# https://github.com/hashicorp/nomad/blob/v0.12.3/command/job_plan.go#L609
+def get_diff_string(diff_type: str) -> Tuple[str, int]:
+    if diff_type == "Added":
+        return f"[green]+[reset] ", 2
+    elif diff_type == "Deleted":
+        return f"[red]-[reset] ", 2
+    elif diff_type == "Edited":
+        return f"[light_yellow]+/-[reset] ", 4
+    else:
+        return "", 0
+
+
+# https://github.com/hashicorp/nomad/blob/v0.12.3/command/job_plan.go#L590
+def get_longest_prefixes(fields: Optional[List[FieldDiff]], objects: Optional[List[ObjectDiff]]) -> Tuple[int, int]:
+    if fields is None:
+        fields = []
+    if objects is None:
+        objects = []
+
+    longest_field = longest_marker = 0
+
+    for field in fields:
+        l = len(field.Name)
+        if l > longest_field:
+            longest_field = l
+
+        _, l = get_diff_string(field.Type)
+        if l > longest_marker:
+            longest_marker = l
+
+    for obj in objects:
+        _, l = get_diff_string(obj.Type)
+        if l > longest_marker:
+            longest_marker = l
+
+    return longest_field, longest_marker
+
+
+# https://github.com/hashicorp/nomad/blob/v0.12.3/command/job_plan.go#L555
+def aligned_field_and_objects(
+        fields: Optional[List[FieldDiff]],
+        objects: Optional[List[ObjectDiff]],
+        start_prefix: int,
+        longest_field: int,
+        longest_marker: int) -> str:
+
+    if fields is None:
+        fields = []
+    if objects is None:
+        objects = []
+
+    out = ""
+    num_fields = len(fields)
+    num_objects = len(objects)
+    have_objects = num_objects != 0
+
+    for i, field in enumerate(fields):
+        _, mLength = get_diff_string(field.Type)
+        kPrefix = longest_marker - mLength
+        vPrefix = longest_field - len(field.Name)
+        out += format_field_diff(field, start_prefix, kPrefix, vPrefix)
+
+        # Avoid a dangling new line
+        if i+1 != num_fields or have_objects:
+            out += "\n"
+
+    for i, object in enumerate(objects):
+        _, mLength = get_diff_string(object.Type)
+        kPrefix = longest_marker - mLength
+        out += format_object_diff(object, start_prefix, kPrefix)
+
+        # Avoid a dangling new line
+        if i+1 != num_objects:
+            out += "\n"
+
+    return out
+
+
+# https://github.com/hashicorp/nomad/blob/v0.12.3/command/job_plan.go#L624
+def color_annotations(annotations: Optional[List[str]]) -> str:
+    if not annotations:
+        return ""
+
+    colord = []
+    for annotation in annotations:
+        if annotation == "forces create":
+            colord.append(f'[green]{annotation}[reset]')
+        elif annotation == "forces destroy":
+            colord.append(f'[red]{annotation}[reset]')
+        elif annotation == "forces in-place update":
+            colord.append(f'[cyan]{annotation}[reset]')
+        elif annotation == "forces create/destroy update":
+            colord.append(f'[yellow]{annotation}[reset]')
+        else:
+            colord.append(annotation)
+
+    return ", ".join(colord)

nomad_diff/models.py

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+from __future__ import annotations
+from typing import List, Optional, Dict
+
+from pydantic import BaseModel
+
+
+class JobDiff(BaseModel):
+    Fields: Optional[List[FieldDiff]]
+    ID: str
+    Objects: Optional[List[ObjectDiff]]
+    TaskGroups: Optional[List[TaskGroupDiff]]
+    Type: str
+
+
+class TaskGroupDiff(BaseModel):
+    Fields: Optional[List[FieldDiff]]
+    Name: str
+    Objects: Optional[List[ObjectDiff]]
+    Tasks: Optional[List[TaskDiff]]
+    Type: str
+    Updates: Optional[Dict[str, int]]
+
+
+class FieldDiff(BaseModel):
+    Annotations: Optional[List[str]]
+    Name: str
+    New: str
+    Old: str
+    Type: str
+
+
+class ObjectDiff(BaseModel):
+    Fields: List[FieldDiff]
+    Name: str
+    Objects: Optional[List[ObjectDiff]]
+    Type: str
+
+
+class TaskDiff(BaseModel):
+    Type: str
+    Name: str
+    Fields: Optional[List[FieldDiff]]
+    Objects: Optional[List[ObjectDiff]]
+    Annotations: Optional[List[str]]
+
+
+ObjectDiff.update_forward_refs()
+JobDiff.update_forward_refs()
+TaskGroupDiff.update_forward_refs()
+
+

setup.py

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+from setuptools import setup
+
+setup(
+    name='nomad-diff',
+    version='1.0.0',
+    description='Nomad job diff formatter in Python',
+    author='Strigo.io',
+    author_email='[email protected]',
+    python_requires='>=3.7',
+    url='https://github.com/strigo/nomad-diff',
+    packages=['nomad_diff'],
+    install_requires=[
+        'pydantic~=1.6.1',
+        'colorama~=0.4.3',
+    ],
+    include_package_data=True,
+    license='MIT',
+    classifiers=[
+        'License :: OSI Approved :: Apache Software License',
+        'Programming Language :: Python',
+        'Programming Language :: Python :: 3',
+        'Programming Language :: Python :: 3.7',
+        'Programming Language :: Python :: Implementation :: CPython',
+        'Topic :: Software Development :: Libraries'
+    ],
+)